Archive | shield

Tutorial – Arduino Mega and SM5100B GSM Cellular

Shield is now out of date so tutorial has been removed. Contact your hardware supplier for support.

Posted in arduino, GSM, shield, tronixlabs, tronixstuff, tutorial

Tutorial – Arduino and MediaTek 3329 GPS

Learn how to use MediaTek 3329-based GPS shields with Arduino in Chapter 19 of our Arduino Tutorials. The first chapter is here, the complete series is detailed here. If you have an EM406A GPS module, please visit the separate tutorial. Updated 15/01/2014

Introduction

In this instalment we will introduce and examine the use of the Global Positioning System receivers with Arduino systems. What is the GPS? In very simple terms, a fleet of satellites orbit the earth, transmitting signals from space. Your GPS receiver uses signals from these satellites to triangulate position, altitude, compass headings, etc.; and also receives a time and date signal from these satellites.

The most popular GPS belongs to the USA, and was originally for military use – however it is now available for users in the free world.

Interestingly, the US can switch off or reduce accuracy of their GPS in various regions if necessary, however many people tell me this is not an issue unless you’re in a combat zone against the US forces. For more information, have a look at Wikipedia or the USAF Space Command GPS Ops Centre site. As expected,  other countries have their own GPS as well – such as Russia, China, and the EU is working on one as well.

So – how can us mere mortals take advantage of a multi-billion dollar space navigation system just with our simple Arduino? Easy – with an inexpensive GPS receiver and shield. In this tutorial we’ll use a GPS shield based on the MediaTek3329 GPS receiver from Tronixlabs.

Unlike the EM406A used in the other tutorial, the whole lot is all on one shield – and after some experimenting has better reception. Plus there’s an onboard SD card socket which we’ll use for a GPS logging device. The only catch is that you need to solder the stacking headers yourself. (update – if purchased from Tronixlabs these will be fully assembled):

Linksprite Arduino GPS SD card shield

Apart from the GPS shield we’ll also be using a typical Arduino-compatible LCD shield and of course an Arduino Uno or compatible. Finally before getting started, you need to set the two jumpers on the GPS shield as shown in the following image:

Linksprite GPS Arduino shield jumpers

By doing this the serial data lines from the GPS receiver can be connected to Arduino D2 and D3 – which we will use with SoftwareSerial. The benefit of doing it this way is that you can then upload sketches without any hardware changes and also use the serial monitor and GPS at the same time. So let’s get started.

Testing your GPS shield

Simply connect your GPS shield as described above to your Arduino Uno or compatible, and upload the following sketch:

Note the use of SoftwareSerial in the sketch. As mentioned earlier, the GPS data is transferred to the Arduino via D2/D2 – which we set up as a software serial port.

If possible try to get your hardware close to a window, then open the serial monitor window. The first time you power up your receiver, it may take a  minute or so to lock onto the available satellites, this period of time is the cold start time.

The subsequent times you power it up, the searching time is reduced somewhat as our receiver stores some energy in a supercap (very high-value capacitor) to remember the satellite data, which it will use the next time to reduce the search time (as it already has a “fair idea” where the satellites are).

Moving on, after a few moments you should be presented with a scrolling wall of text, for example:

Arduino GPS raw NMEA data

What on Earth does all that mean? For one thing the hardware is working correctly. Excellent! Now how do we decode these space-signals… They are called NMEA codes. Let’s break down one and see what it means. For example, the line:

  • $GPRMC tells us the following data is essential point-velocity-time data;
  • 100748.000 is the universal time constant (Greenwich Mean Time) – 10:07:48 (hours, minutes, seconds). So you now have a clock as well.
  • A is status – A for active and data is valid, V for void and data is not valid.
  • 3754.9976  is degrees latitude position data = 37 degrees, 54.9976′
  • S for south (south is negative, north is positive)
  • 14507.0283 is degrees longitude position data = 145 degrees, 07.0283′
  • E for east (east is positive, west is negative)
  • 0.00 is my speed in knots over ground. This shows the inaccuracy  that can be caused by not having a clear view of the sky
  • 263.36 – course over ground (0 is north, 180 is south, 270 is west, 90 is east)
  • 140114 is the date – 14th January 2014
  • the next is magnetic variation for which we don’t have a value
  • checksum number

Thankfully the data is separated by commas. This will be useful later when you log the data to a text file using the SD card, as you will then be able to use the data in a spreadsheet very easily. For more explanation about the data, here is the NMEA Reference Manual that explains them all.

Extracting the GPS data

You can’t decode all that NMEA on the fly, so thankfully there is an Arduino library to do this for us – TinyGPS. So head over to the library website, download and install the library before continuing.

Now with the same hardware from the previous example, upload the following sketch:

How this works is quite simple. In void loop() the sketch waits for data to come from the GPS receiver, and then checks if it’s valid GPS data. Then it passes over to the function getgps() which uses the function:

to extract the location data and place it in two variables. Next, another function:

will extract the date and time data, and place them in the pre-determined variables. Finally the use of

and

can be assigned to variables as they store the altitude and speed respectively. These functions will be commonly used across all the examples, so you can see how they can be used.

To test the sketch, position the hardware and open the serial monitor. After a moment you should be presented with the GPS data in a much more useful form, for example:

Arduino GPS data

At this point you should be able to form ideas of how to harness that data and display or work with it in a more useful way. Useful hint – you can enter coordinates directly into Google Maps to see where it is, for example:

GPS data in Google Maps

 A portable GPS display

Now that you can extract the GPS data, it’s a simple matter of sending it to an LCD shield for display. Just add the LCD shield to your hardware and upload the next sketch. Be sure to change the values in the LiquidCrysal LCD… line if your shield uses different digital pins.

Again, position the hardware and your current position should be shown on the LCD, for example:

Arduino GPS LCD

A GPS Clock

Armed with the same hardware you can also create a GPS clock. With this you can finally have a reference clock and end all arguments about the correct time without calling the speaking clock. Just use the same hardware from the previous example and upload the following sketch:

Now position the hardware again, and after a moment the time will appear – as shown in this video.

Unless you live in the UK or really need to know what GMT/UTC is, a little extra work is required to display your local time. First you will need to know in which time zone you are located – find it in this map.

If your time zone is positive (e.g. GMT +10) – you need to add 10 to your hour value, and if it’s over 23 you then subtract 24 to get the correct hours.

If your time zone is negative (e.g. GMT – 5) – you need to subtract 5 from your hour value, and if it’s under zero  you then add 24 to get the correct hours.

GPS Speedometer

Just as with the clock, it’s easy to display the speed readings with the LCD. Using the same hardware as above, enter and upload the following sketch:

Now position the hardware again, and after a moment your speed should appear. You might get some odd readings if indoors, as the receiver needs data from several satellites to accurately determine your speed. The sketch is written for km/h, however you can replace the display lines with the section that is commented out to display miles per hour.

So at this point find a car and driver, an external power supply and go for a drive. You may find the GPS speed is quite different to the vehicle’s speedometer.

Build a GPS logging device

And for our final example, let’s make a device that captures the position, speed and time data to SD card for later analysis. The required hardware is just the GPS shield and Arduino Uno or compatible board – plus an SD memory card that is formatted to FAT16. SDXC cards may or may not work, they’re quite finicky – so try and get an older standard card.

Now enter and upload the following sketch:

This will append the data to a text file whose name is determine in line 34 of the sketch. If you are using a different GPS shield or a separate SD card shield you may need to change the digital pin value for the chip select line, which is found in lines 14 and 18. The data in our example is logged every ten seconds, however you can change the frequency using the delay() function in line 73.

When you’re ready to start capturing data, simply insert the card and power up the hardware. It will carry on until you turn it off, at which point the data file can be examined on a PC. As an example capture, I took the hardware for a drive, and ended with a file containing much data – for example:

Arduino GPS logging example data

For a more graphical result, you can import the data using a third-party service into Google Maps to get a better idea of the journey. But first, the text file requires a little work. Open it as a text file using a typical spreadsheet, which will then ask how to organise the columns. Delimit them with a space, for example:

delimit Arduino GPS data

Which will give you a spreadsheet of the data. Now delete all the columns except for the latitude and longitude data, and add a header row as such:

GPS data in spreadsheet

Now save that file as an .xls spreadsheet. Next, visit the GPS Visuliser website, and upload the file using the box in the centre of the page. Select “Google Maps” as the output format, and your trip will be presented – for example:

GPS trip map

There are many options on the visualiser site, so if you end up using it a lot – consider giving them a donation.

Conclusion

Now you have some easy example sketches that demonstrate how to extract and work with data from your GPS shield. For the curious, the static GPS locations displayed in this tutorial are not our current location. And if you enjoyed this article, or want to introduce someone else to the interesting world of Arduino – check out my book (now in a third printing!) “Arduino Workshop”.

visit tronixlabs.com

Have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column, or join our forum – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

Posted in arduino, GPS, Mediatek 3329, shield, SKM58, tronixlabs, tronixstuff, tutorial0 Comments

Arduino Tutorials – Chapter 16 – Ethernet

Learn how to connect your Arduino to the outside world via Ethernet

This is chapter sixteen of our huge Arduino tutorial seriesUpdated 06/12/2013

In this chapter we will introduce and examine the use of Ethernet networking with Arduino over local networks and the greater Internet. It will be assumed that you have a basic understanding of computer networking, such as the knowledge of how to connect computers to a hub/router with RJ45 cables, what an IP and MAC address is, and so on. Furthermore, here is a good quick rundown about Ethernet.

Getting Started

You will need an Arduino Uno or compatible board with an Ethernet shield that uses the W5100 Ethernet controller IC (pretty much all of them):

Arduino Ethernet shield

…or consider using a Freetronics EtherTen – as it has everything all on the one board, plus some extras:

Freetronics EtherTen

Furthermore you will need to power the board via the external DC socket – the W5100 IC uses more current than the USB power can supply. A 9V 1A plug pack/wall wart will suffice. Finally it does get hot – so be careful not to touch the W5100 after extended use. In case you’re not sure – this is the W5100 IC:

Wiznet W5100

Once you have your Ethernet-enabled Arduino, and have the external power connected – it’s a good idea to check it all works. Open the Arduino IDE and selectFile > Examples > Ethernet > Webserver. This loads a simple sketch which will display data gathered from the analogue inputs on a web browser. However don’t upload it yet, it needs a slight modification.

You need to specify the IP address of the Ethernet shield – which is done inside the sketch. This is simple, go to the line:

And alter it to match your own setup. For example, in my home the router’s IP address is 10.1.1.1, the printer is 10.1.1.50 and all PCs are below …50. So I will set my shield IP to 10.1.1.77 by altering the line to:


You also have the opportunity to change your MAC address. Each piece of networking equipment has a unique serial number to identify itself over a network, and this is normall hard-programmed into the equipments’ firmware. However with Arduino we can define the MAC address ourselves.

If you are running more than one Ethernet shield on your network, ensure they have different MAC addresses by altering the hexadecimal values in the line:


However if you only have one shield just leave it be. There may be the very, very, statistically rare chance of having a MAC address the same as your existing hardware, so that would be another time to change it.

Once you have made your alterations, save and upload the sketch. Now open a web browser and navigate to the IP address you entered in the sketch, and you should be presented with something similar to the following:

 Arduino webserver example sketch

What’s happening? The Arduino has been programmed to offer a simple web page with the values measured by the analogue inputs. You can refresh the browser to get updated values.

At this point – please note that the Ethernet shields use digital pins 10~13, so you can’t use those for anything else. Some Arduino Ethernet shields may also have a microSD card socket, which also uses another digital pin – so check with the documentation to find out which one.

Nevertheless, now that we can see the Ethernet shield is working we can move on to something more useful. Let’s dissect the previous example in a simple way, and see how we can distribute and display more interesting data over the network. For reference, all of the Ethernet-related functions are handled by the Ethernet Arduino library. If you examine the previous sketch we just used, the section that will be of interest is:

Hopefully this section of the sketch should be familiar – remember how we have used serial.print(); in the past when sending data to the serial monitor box? Well now we can do the same thing, but sending data from our Ethernet shield back to a web browser – on other words, a very basic type of web page.

However there is something you may or may not want to  learn in order to format the output in a readable format – HTML code. I am not a website developer (!) so will not delve into HTML too much.

However if you wish to serve up nicely formatted web pages with your Arduino and so on, here would be a good start. In the interests of simplicity, the following two functions will be the most useful:


Client.print (); allows us to send text or data back to the web page. It works in the same way as serial.print(), so nothing new there. You can also specify the data type in the same way as with serial.print(). Naturally you can also use it to send data back as well. The other useful line is:


which sends the HTML code back to the web browser telling it to start a new line. The part that actually causes the carriage return/new line is the <br /> which is an HTML code (or “tag”) for a new line. So if you are creating more elaborate web page displays, you can just insert other HTML tags in the client.print(); statement. If you want to learn more about HTML commands, here’s a good tutorial site. Finally – note that the sketch will only send the data when it has been requested, that is when it has received a request from the web browser.

Accessing your Arduino over the Internet

So far – so good. But what if you want to access your Arduino from outside the local network?

You will need a static IP address – that is, the IP address your internet service provider assigns to your connection needs to stay the same. If you don’t have a static IP, as long as you leave your modem/router permanently swiched on your IP shouldn’t change. However that isn’t an optimal solution.

If your ISP cannot offer you a static IP at all, you can still move forward with the project by using an organisation that offers a Dynamic DNS. These organisations offer you your own static IP host name (e.g. mojo.monkeynuts.com) instead of a number, keep track of your changing IP address and linking it to the new host name. From what I can gather, your modem needs to support (have an in-built client for…) these DDNS services. As an example, two companies are No-IP andDynDNS.com. Please note that I haven’t used those two, they are just offered as examples.

Now, to find your IP address… usually this can be found by logging into your router’s administration page – it is usually 192.168.0.1 but could be different. Check with your supplier or ISP if they supplied the hardware. For this example, if I enter 10.1.1.1 in a web browser, and after entering my modem administration password, the following screen is presented:

WAN IP address router

What you are looking for is your WAN IP address, as you can see in the image above. To keep the pranksters away, I have blacked out some of my address.

The next thing to do is turn on port-forwarding. This tells the router where to redirect incoming requests from the outside world. When the modem receives such a request, we want to send that request to the port number of our Ethernet shield. Using the:

function in our sketch has set the port number to 125. Each modem’s configuration screen will look different, but as an example here is one:

Arduino router port forwarding

So you can see from the line number one in the image above, the inbound port numbers have been set to 125, and the IP address of the Ethernet shield has been set to 10.1.1.77 – the same as in the sketch.

After saving the settings, we’re all set. The external address of my Ethernet shield will be the WAN:125, so to access the Arduino I will type my WAN address with :125 at the end into the browser of the remote web device, which will contact the lonely Ethernet hardware back home.

Furthermore, you may need to alter your modem’s firewall settings, to allow the port 125 to be “open” to incoming requests. Please check your modem documentation for more information on how to do this.

Now from basically any Internet connected device in the free world, I can enter my WAN and port number into the URL field and receive the results. For example, from a phone when it is connected to the Internet via LTE mobile data:

Arduino webserver example cellular

So at this stage you can now display data on a simple web page created by your Arduino and access it from anywhere with unrestricted Internet access. With your previous Arduino knowledge (well, this is chapter sixteen) you can now use data from sensors or other parts of a sketch and display it for retrieval.

Displaying sensor data on a web page

As an example of displaying sensor data on a web page, let’s use an inexpensive and popular temperature and humidity sensor – the DHT22. You will need to install the DHT22 Arduino library which can be found on this page. If this is your first time with the DHT22, experiment with the example sketch that’s included with the library so you understand how it works.

Connect the DHT22 with the data pin to Arduino D2, Vin to the 5V pin and GND to … GND:

arduino ethernet freetronics etherten dht22 humid

Now for our sketch – to display the temperature and humidity on a web page. If you’re not up on HTML you can use online services such as this to generate the code, which you can then modify to use in the sketch.

In the example below, the temperature and humidity data from the DHT22 is served in a simple web page:

It is a modification of the IDE’s webserver example sketch that we used previously – with a few modifications. First, the webpage will automatically refresh every 30 seconds – this parameter is set in the line:

… and the custom HTML for our web page starts below the line:

You can then simply insert the required HTML inside client.print() functions to create the layout you need.

Finally – here’s an example screen shot of the example sketch at work:

arduino ethernet freetronics etherten dht22 humid cellular

You now have the framework to create your own web pages that can display various data processed with your Arduino.

Remote control your Arduino from afar

We have a separate tutorial on this topic, that uses the teleduino system.

Conclusion

So there you have it, another useful way to have your Arduino interact with the outside world. Stay tuned for upcoming Arduino tutorials by subscribing to the blog, RSS feed (top-right), twitter or joining our Google Group. And if you enjoyed the tutorial, or want to introduce someone else to the interesting world of Arduino – check out my book (now in a third printing!) “Arduino Workshop” from No Starch Press.

tronixstuff

Posted in arduino, DEV-09026, DEV-11230, DHT22, ethernet, internet, iot, shield, tronixstuff, tutorial12 Comments

Arduino Tutorials – Chapter 30 – twitter

Learn how to tweet from your Arduino.

This is chapter thirty of our huge Arduino tutorial seriesUpdated 16/06/2014

In this article you will learn how to send messages from an Ethernet-enabled Arduino to twitter. For the uninitiated who may be thinking “what is all this twitter nonsense about?”, twitter is a form of microblogging. 

You can create a message with a maximum length of 140 characters, and broadcast this on the twitter service. For people to receive your messages (or tweets) they also need to be a member of twitter and choose to subscribe to your tweets.

Generally people will use the twitter service using one of two methods: either using a web browser, or using the twitter application on a smartphone or tablet computer. For example, here is a typical web browser view:

twitter web browser

… and here is an example of a twitter application running on an Android OS smartphone:

twitter android

The neat thing about twitter on a mobile device is that if your username is mentioned in a tweet, you will be notified pretty well immediately as long as you have mobile data access. More on that later. In some areas, you can set twitter to send tweets from a certain user to your mobile phone via SMS – however if doing so be careful to confirm possible charges to your mobile phone account.

Finally, if you are worried about privacy with regards to your tweets, you can set your account to private and only allow certain people to follow your tweets.

So let’s get started.

First of all – you will need a twitter account. If you do not have one, you can sign up for one here. If you already have a twitter account, you can always open more for other uses – such as an Arduino.

For example, my twitter account is @tronixstuff, but my demonstration machine twitter account is @tronixstuff2. Then I have set my primary account to follow my machine’s twitter account.

Now log into twitter with using the account you will have for your Arduino and visit this page and get yourself a token by following the Step One link. The process will take you through authorising the “tweet library” page to login to your twitter account – this is ok. It will then present you with a long text called a “token”, for example:

twitter oauth token

Save your token somewhere safe, as you will need to insert it into your Arduino sketch. Finally, don’t give it to others as then they will be able to post onto twitter using your account. Next, follow step two from the same page – which involves download and installation of the required Arduino library.

Now for the hardware.

You will need an Arduino Uno or compatible board with an Ethernet shield that uses the W5100 Ethernet controller IC (pretty much all of them) – or consider using a Freetronics EtherTen – as it has everything all on the one board, plus some extras:

Freetronics EtherTen

Furthermore you will need to power the board via the external DC socket – the W5100 IC uses more current than the USB power can supply. A 9V 1A plug pack/wall wart will suffice. Finally it does get hot – so be careful not to touch the W5100 after extended use. In case you’re not sure – this is the W5100 IC:

Wiznet W5100If you’re looking for an Arduino-twitter solution with WiFi, check out the Arduino Yún tutorials.

From this point it would be a good idea to check your hardware is working. To do so, please run the webserver example sketch as explained in chapter sixteen (Ethernet). While you do that, we’ll have a break…

Lop Buri Thailand

Sending your first tweet

If you want your Arduino to send a simple tweet consider the following sketch. We have a simple function tweet() which simply sends a line of text (which has a maximum length of 140 characters). Don’t forget to update your IP address, MAC address and token:

You can check the status of the tweeting via the serial monitor. For example, if the tweet was successful you will see:

arduino twitter success 2014

However if you try to send the same tweet more than once in a short period of time, or another error takes place – twitter will return an error message, for example:

arduino twitter duplicate

And finally if it works, the tweet will appear:

Arduino twitter works 2014

Previously we mentioned that you can be alerted to a tweet by your mobile device. This can be done by putting your own twitter account name in the contents of the tweet.

For example – my normal twitter account is @tronixstuff. If I put the text “@tronixstuff” in the text tweeted by my Arduino’s twitter account – the twitter app on my smartphone will let me know I have been mentioned – as shown in the following video:

You may have noticed in the video that a text message arrived as well – that service is a function of my cellular carrier (Telstra) and may not be available to others. Nevertheless this is a neat way of getting important messages from your Arduino to a smart phone or other connected device.

Sending data in a tweet

So what if you have  a sensor or other device whose data you want to know about via twitter? You can send data generated from an Arduino sketch over twitter without too much effort.

In the following example we’ll send the value from analogue pin zero (A0) in the contents of a tweet. And by adding your twitter @username you will be notified by your other twitter-capable devices:

You may have noticed a sneaky sprintf function in void loop(). This is used to insert the integer analogZero into the character array tweetText that we send with the tweet() function. And the results of the example:

Arduino Twitter Tutorial success

So you can use the previous sketch as a framework to create your own Arduino-powered data twittering machine. Send temperature alerts, tank water levels, messages from an alarm system, or just random tweets to your loved one.

Conclusion

So there you have it, another useful way to send information from your Arduino to the outside world. Stay tuned for upcoming Arduino tutorials by subscribing to the blog, RSS feed (top-right), twitter or joining our Google Group. Big thanks to @neocat for their work with the twitter  Arduino libraries.

And if you enjoyed the tutorial, or want to introduce someone else to the interesting world of Arduino – check out my book (now in a third printing!) “Arduino Workshop” from No Starch Press.

tronixstuff

In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

Posted in arduino, ethernet, shield, tronixstuff, tutorial, twitter5 Comments

Review – Freetronics EtherMega

In this review we take a look at what is possibly the most fully-featured Arduino compatible board on the market today – the Freetronics EtherMega. This board combines the functionality of an Arduino Mega2560, a microSD card shield, and an Ethernet shield that supports power over Ethernet with optional 802.3af standard. So instead of having these three mashed together at a great expense:

thelot

… you can have this:

Freetronics EtherMega Tronixlabs Australia

Which saves space, time and money. Firstly, the specifications:

  • 100% compatible with the Arduino Mega2560. So you have the ATmega2560 microcontroller, 54 digital I/O pins with 14 PWM-capable, 256KB of flash memory, 8KB of SRAM and 4KB of EEPROM to play with, the Atmel 16u2 micrcontroller taking care of the USB interface;
  • However unlike the original, the EtherMega contains a switchmode power supply that allows operation from a DC power supply of between 7 and 28VDC without overheating;
  • Complete c0mpatibility with the Arduino Ethernet shield, using the Wiznet W5100 controller just like the original;
  • Network status LEDs on both the socket and the PCB;
  • Fixed SPI behaviour on Ethernet chipset;
  • Complete microSD card compatibility with SD library, and chip-select is on digital pin 4 so Ethernet and microSD can work together on the same sketch;
  • optional 802.3af power over Ethernet support at up to 48V using the optional regulator board which mounts on the EtherMega;
  • mini USB connector instead of the larger standard USB socket which can interfere with shields – and a USB cable is included

Furthermore there are a few modifications to make using the EtherMega easier or simpler. The first of these is the onboard prototyping area allowing you to add your own circuitry:

Also notice that the I2C pins have been brought out alongside the 5V and GND pins on the right. The only difference to take note of are the jumpers that are used to select either USB or DC socket power:

However that is a small price to pay compared to the convenience of the wide voltage-handling capability. Finally, unlike the original Arduino Mega2560 the designers have placed the TX/RX indicators at the top-left of the EtherMega so they are still visible when extra shields have been mounted:

The overall design and quality of the EtherMega is top notch, with a thick PCB, rounded corners, descriptive silk-screening, and packaging that can be reused as Mega or other part storage.

If you are looking for an Arduino Mega2560 and could use Ethernet, power-over-Ethernet, a microSD card interface and full, 100% Arduino compatibility you could do a lot worse than getting yourself an EtherMega. If you are interested in learning how to use Arduino and Ethernet – check out our tutorial here. Or to get your Arduino tweeting, visit here.

And if you enjoyed this article, or want to introduce someone else to the interesting world of Arduino – check out my book (now in a fourth printing!) “Arduino Workshop”.

visit tronixlabs.com

Have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column, or join our forum – dedicated to the projects and related items on this website.

Posted in 802.3af, arduino, ethermega, ethernet, freetronics, review, shield, tronixlabs0 Comments

Moving Forward with Arduino – Chapter 16 – Ethernet

Use Ethernet with Arduino in chapter sixteen of “Getting Started with Arduino!” by John Boxall – A tutorial on the Arduino universe. The first chapter is here, the complete series is detailed here.

[Updated 09/01/2013]

In this instalment we will introduce and examine the use of Ethernet networking with Arduino systems. This tutorial covers receiving data from an Arduino over the Internet. If you are interested in controlling an Arduino over the Internet, see here. It will be assumed that you have a basic understanding of computer networking, such as the knowledge of how to connect computers to a hub/router with RJ45 cables, what an IP and MAC address is, and so on. Furthermore, here is a good quick rundown about Ethernet.

First of all, you will need an Ethernet shield. There are a few on the market, such as the original version by the Arduino team. Readers of my articles will know my preference is for the Australian-designed Freetronics line of hardware, so I will be using their EtherTen – which combines an Arduino Uno-compatible board with an Ethernet shield. Plus it also has some interesting power-over-Ethernet features which you can read about here. However as long as your Arduino Ethernet shield has the W5100 controller IC – you’re fine.

Now, let’s get started!

This is an ethernet shield on top of an Arduino-compatible board. Nothing new here – just a nice RJ45 socket which you connect to your router/hub/modem with a patch lead:

shieldbss

First of all, let’s do something quick and easy to check that all is functional. Open the Arduino IDE and select File > Examples > Ethernet > Webserver. This loads a simple sketch which will display data gathered from the analogue inputs on a web browser. However don’t upload it yet, it needs a slight modification.

You need to specify the IP address of the ethernet shield – which is done inside the sketch. This is simple, go to the line:

And alter it to match your own setup. For example, in my home the router’s IP address is 10.1.1.1, the printer is 10.1.1.50 and all PCs are below …50. So I will set my shield IP to 10.1.1.77 by altering the line to:

You also have the opportunity to change your MAC address. Each piece of networking equipment has a unique serial number to identify itself over a network, and this is normall hard-programmed into the equipments’ firmware. However with Arduino we can define the MAC address ourselves. If you are running more than one ethernet shield on your network, ensure they have different MAC addresses by altering the hexadecimal values in the line:

However if you only have one shield just leave it be. There may be the very, very, statistically rare chance of having a MAC address the same as your existing hardware, so that would be another time to change it. Once you have made your alterations, save and upload the sketch to your Arduino or compatible board. If you haven’t already, disconnect the power and add your Ethernet shield.

Now, connect the shield to your router or hub with an RJ45 cable, and the Arduino board to the power via USB or external power supply. Then return to your computer, and using your web browser, enter your Ethernet shield’s IP address into the URL bar. The web browser will query the Ethernet shield, which will return the values from the analogue ports on the Arduino board, as such:

As there isn’t anything plugged into the analog inputs, their value will change constantly. Neat – your Arduino is now serving data over a network. It is quite motivating to see it actually work.

At this point – please note that the Ethernet shields use digital pins 10~13, so you can’t use those for anything else. Some Arduino Ethernet shields may also have a microSD card socket, which also uses another digital pin – so check with the documentation to find out which one. If you are considering using an Arduino Mega and Ethernet – check out the EtherMega.

Nevertheless, now that we can see the Ethernet shield is working we can move on to something more useful. Let’s dissect the previous example in a simple way, and see how we can distribute and display more interesting data over the network. For reference, all of the Ethernet-related functions are handled by the Ethernet Arduino library. If you examine the previous sketch we just used, the section that will be of interest is:

Hopefully this section of the sketch should be familiar – remember how we have used serial.print(); in the past when sending data to the serial monitor box? Well now we can do the same thing, but sending data from our Ethernet shield back to a web browser – on other words, a very basic type of web page. However there is something you may or may not want to  learn in order to format the output in a readable format – HTML code. I am not a website developer (!) so will not delve into HTML too much.

However if you wish to serve up nicely formatted web pages with your Arduino and so on, here would be a good start. In the interests of simplicity, the following two functions will be the most useful:

Client.print (); allows us to send text or data back to the web page. It works in the same way as serial.print(), so nothing new there. You can also specify the data type in the same way as with serial.print(). Naturally you can also use it to send data back as well. The other useful line is:

this sends the HTML code back to the web browser telling it to start a new line. The part that actually causes the carriage return/new line is the <br /> which is an HTML code (or “tag”) for a new line. So if you are creating more elaborate web page displays, you can just insert other HTML tags in the client.print(); statement.

Note that the sketch will only send the data when it has been requested, i.e. received a request from the web browser. So let’s put our new knowledge into action with some simple sensor hardware – measuring temperature and pseudo-light levels. In chapter fourteen we did this and sent the results over the air using XBee wireless modules. Now we shall make that data available to a web browser instead.

We will need:

  • Arduino Uno or compatible board and Ethernet shield, or
  • Freetronics EtherTen
  • Analog Devices TMP36 temperature sensor
  • 10 k ohm resistor
  • light-dependent resistor/photocell

Here is the schematic for the circuit:

example16p1sch

and in real life. If you were to construct a permanent application, the Freetronics shield is great as you have all that prototyping space:

exam16p1hardss

and download the sketch from here. Finally, the example in action, on the desktop PC:

exam16p1chrome

… and on a phone via my internal wireless access point (the screen is a little fuzzy due to the adhesive screen protector):

exam16p1desiress

Now you can see how easy it is to send data from your Arduino via an Ethernet network to a web browser. But that is only to a local web browser. What if I wanted to read that data using my phone from an Internet cafe in downtown Vientiane? It can be done, but is a little bit tricky for the uninitiated – so let’s get initiated!

You will need a static IP address – that is, the IP address your internet service provider assigns to your connection needs to stay the same. If you don’t have a static IP, as long as you leave your modem/router permanently swiched on your IP shouldn’t change.

However, if your internet service provider cannot offer you a static IP at all, you can still move forward with the project by using an organisation that offers a Dynamic DNS. These organisations offer you your own static IP hostname (e.g. mojo.monkeynuts.com) instead of a number, keep track of your changing IP address and linking it to the new hostname. From what I can gather, your modem needs to support (have an in-built client for…) these DDNS services. As an example, two companies are No-IP and DynDNS.com. Please note that I haven’t used those two***, they are just offered as examples.

Now, to find your IP address, usually this can be found by logging into your router’s administration page. For this example, if I enter 192.168.0.1 in a web browser, and after entering my modem administration password, the following screen is presented:

wanip

What you are looking for is your WAN IP address, as artistically circled above. To keep the pranksters away, I have blacked out some of my address. The next thing to do is turn on port-forwarding. This tells the router where to redirect incoming requests from the outside world. When the modem receives such a request, we want to send that request to the port number of our Ethernet shield. Using the Server server(80); function in our sketch has set the port number to 80. Each modem’s configuration screen will look different, but as an example here is one:

bobportfwdss

So you can see from the line number one, the inbound port numbers have been set to 80, and the IP address of the Ethernet shield has been set to 192.168.0.77 – the same as in the sketch. After saving the settings, we’re all set. The external address of my Ethernet shield will be the WAN:80, e.g.  213.123.456.128:80 into the browser of a web device will contact the lonely Ethernet hardware back home. Furthermore, you may need to alter your modem’s firewall settings, to allow the port 80 to be “open” to incoming requests. Please check your modem documentation for more information on how to do this.

Now from basically any Internet connected device in the free world, I can enter my WAN and port number into the URL field and receive the results. For example, from a phone when it is connected to the Internet via 3.5G mobile data:

How neat is that? The web page, not the phone. Well, the phone is pretty awesome too.

OK, it’s just the temperature – but with your other Arduino knowledge from our tutorials and elsewhere – you can wire up all sorts of sensors, poll them from your Arduino and use the Ethernet shield and an Internet connection to access that data from anywhere. Here are some applications that spring to mind, all can be made possible with details from our previous tutorials:

  • Sensitive temperature monitoring (e.g. a smoke house, tropical fish tank, chemical storage room, and so on);
  • “Have the children come home from school?” – children must swipe their RFID tag when they arrive home. Arduino stores time and tag number, which can be converted into display data for web output;
  • For single room-mates – perhaps a remote, high-tech version of a necktie on a doorknob… when the “busy” flatmate arrives home, they turn a switch which is read by the Arduino, and is then polled by the sketch – the other flatmates can poll from their phone before coming home;
  • Using reed switch/magnet pairs, you could monitor whether important doors or windows (etc.) were open or closed.
  • A small RFID could be placed on the collar of your pet – two RFID readers on each side of a cat/dog flap door. Using simple logic the Arduino could calculate if the pet was inside or outside, and the last time the pet went through the door.
  • send twitter messages

The possibilities are only limited by your imagination or requirements.

LEDborder

Have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column, or join our Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

Posted in arduino, DEV-09026, education, ethernet, etherten, learning electronics, lesson, microcontrollers, shield, tronixstuff, tutorial13 Comments

Let’s make an Arduino LCD shield

In this short tutorial we make an Arduino LCD shield.

Updated 18/03/2013

Today we are going to make an Arduino shield with an LCD module. More often than not I have needed to use an LCD shield in one of my projects, or with the Arduino tutorials. Naturally you can buy a pre-made one, however doing your own is always fun and nice way to pass an afternoon. Before we start, let me say this: “to fail to plan is to plan to fail”.  That saying is very appropriate when it comes to making your own shields.

The first step is to gather all of the parts you will need. In this case:

  • an LCD module (backlit if possible, but I’m being cheap and using a non-backlit module) that is HD44780-compatible
  • a 10k linear trimpot, used to adjust the LCD contrast
  • a blank protoshield that matches your Arduino board
  • various header pins required to solder into the shield (they should be included with your protoshield)
  • plenty of paper to draw on

For example:

p1070040small

Next, test your parts to ensure everything works. So, draw a schematic so you have something to follow:

lcdshieldschematic

And then build the circuit on a solderless breadboard, so you can iron out all the hardware bugs before permanently soldering into the shield. If you have a backlit LCD, pins 15 and 16 are also used, 15 for backlight supply voltage (check your data sheet!) and 16 for backlight ground:

p1070043small

Once connected, test the shield with a simple sketch – for example the “HelloWorld” example in the Arduino IDE. Make sure you have the library initialization line:

filled with the appropriate parameters. If you’re not sure about this, visit the LCD display tutorial in my Arduino tutorials.

Now to make the transition from temporary to permanent. Place your components onto the protoshield, and get a feel for how they can sit together. Whilst doing this, take into account that you will have to solder some jumper wires between the various pads and the digital pin contacts and the 5V strip at the top row, as well as the GND strip on the bottom row. You may find that you have to solder jumper wires on the bottom of the shield – that’s fine, but you need to ensure that they won’t interfere with the surface of your Arduino board as well.

Furthermore, some protoshields have extra functions already added to the board. For example, the shield I am using has two LEDs and a switch, so I will need to consider wiring them up as well – if something is there, you shouldn’t waste the opportunity to not use them. If your shield has a solder mask on the rear, a great way to plan your wiring is to just draw them out with a whiteboard marker:

p1070045small

 

Remember to solder these wires in *before* the LCD … otherwise you will be in a whole world of pain. The LCD should be soldered in second-last, as it is the most difficult thing to desolder if you have made any mistakes. The last items to solder will be the header pins. So let’s get soldering…

p1070046small

After every solder joint, I pushed in the LCD module – in order to check my placement. You can never check too many times, even doing so I made a small mistake. Having a magnifying glass handy is also a great idea:

p1070047small

Now just to soldier on, soldering one pad at a time, then checking the joint and its relationship with where it should be on the board. Be very careful when applying solder to the pads, they can act as a “drain” and let lots of solder flow into the other side. If this happens you will spend some time trying to remove that excess solder – a solder sucker and some solder wick is useful for this.

Finally all the wires and pads were connected, and I checked the map once more. Soldering in the LCD was  the easiest part – but it is always the most difficult to remove – so triple check your work before installing the display. Now it was time to sit in the header sockets, and test fit the shield into my arduino board. This is done to make sure there is sufficient space between the wires on the bottom of our shield and the top of the arduino:

p1070049small

Even though you wouldn’t normally put a shield on top of this shield, I used the header sockets to allow access to all of the arduino pins just in case. Soldering the sockets was easy, I used blu-tack to hold them into place. Crude but effective.

p1070053small

And we’re finished. Soldering is not the best of my skills, so I checked continuity between the pins on the LCD and where they were supposed to go, and also electrically checked for bridges between all the soldered pins to check for shorts. A multimeter with a continuity buzzer makes this easy. Naturally I had a short between LCD pin 14 and 13, but some solder wick helped me fix that. So electrically it was correct… time to see if it actually worked! At this point it is a good idea to clear up the workspace, switch off the soldering iron, put it somewhere safe to cool down, then wash your hands thoroughly. Here are some photos of the finished product on my arduino board:

p1070054small

 

p1070055small

As we’re using a Freetronics protoshield with onboard LEDs, the only thing to do was alter the demonstration sketch to take account for the pin placements, and insert some code to blink the LEDs.

I never need an excuse to make a video clip, so here is the result:

So there you have it. With a little planning and care, you too can make your own Arduino shield. An LCD shield would be useful for everyone, as they are great for displaying data and requesting input, yet quite fiddly to use with a solderless breadboard. High resolution photos are available on flickr.

In the meanwhile have fun and keep checking into tronixstuff.com. Why not follow things on twitterGoogle+, subscribe  for email updates or RSS using the links on the right-hand column? And join our friendly Google Group – dedicated to the projects and related items on this website. Sign up – it’s free, helpful to each other –  and we can all learn something.

Posted in arduino, education, HD44780, LCD, projects, shield, tutorial0 Comments


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