Tag Archive | "duo"

Moving Forward with Arduino – Chapter 30 – twitter

Learn how to tweet from your Arduino in chapter thirty of a series originally titled “Getting Started/Moving Forward with Arduino!” by John Boxall – A tutorial on the Arduino universe.

[Updated 26/7/2013]

In this article we will learn how to send messages from our 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 three methods: using a web browser on a personal computer or internet device, on a mobile phone, or using a specific application such as TweetDeck on one of the aforementioned devices. For example, here is a typical web browser view:

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

tweetdeck

So as you can see, it is easy enough to read peoples’ tweets. Therein lies the reason for this article – we can harness twitter as an output device for our Arduino systems. We can broadcast various messages, so systems can be created to monitor specific parameters and report on their status at regular intervals, upon an event occurring, and so on.

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. Once you have logged into twitter with your machine account, visit this page and get yourself a token by following the Step One link. Save your token somewhere safe, you’ll need to insert it into your Arduino sketch.

Next, you will need some hardware. Apart from your usual Arduino board, you will need an Ethernet shield. However to save space and money I’ll be using the Freetronics EtherTen:

If you are unfamiliar with using Arduino and Ethernet, please review chapter sixteen before continuing forward with this article. From a software perspective, we will need another library for our Arduino IDE. Download and install the twitter library from here. Now, at this point – please run the Webserver example described in chapter sixteen and ensure it is working before moving forward from this point. While you do that, we’ll have a break…

lopburi-0606

Now it is time to send our first tweet. The following sketch is a modification of the demonstration version, in which we have isolated the tweet-sending into a separate function called (strangely enough) tweet();. It is not complex at all:

So after uploading the above sketch, running a network cable from your access point to the Ethernet shield, and powering up the Arduino board – your tweet should appear as such:

Excellent – it works. And I hope yours did as well. If it did not, open the serial monitor box to get some feedback from the sketch. From experimentation the most amount of errors are caused by incorrect IP and trying to send multiple tweets too quickly. If you get excited and try to run the sketch again by hitting reset, twitter will reply back with an error – it does not allow duplicate tweets to be sent (over a short period of time). Twitter will reply to your tweet with a code which describes the result of your tweet. This code is stored in an integer variable using the function:

For example, 200 means the tweet was sent successfully, and 403 means you have attempted a duplicate tweet. However you can omit the code-checking if you are not fussed about your tweet’s status.

Although it was fun tweeting Hello world, let’s create an example that reacts to various events and tweets about them. To simulate some events I have connected four buttons to digital inputs (using the button board from chapter twelve). Pressing a button sends of the matching message. However you can use any form of digital output or decision-making in your sketch. For now, here is the example sketch:

And here is a screen shot of the results after pressing buttons one, four, two then three:

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.

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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, cellular, ethernet, learning electronics, microcontrollers, tutorial, twitterComments (2)

Kit review – ogi lumen Nixie Tube system

Hello readers

Time to finish off the month with a fascinating kit review  – the ogi lumen nixie tube system. The younger readers amongst us may be thinking “what is a nixie tube?” Here is an example of four in a row:

p1080918

If you cast your mind back to before the time of LCDs, and before LEDs… to the mid-1950s. Nixie tubes were used to display data in various forms on electrical devices, from test equipment, scales, elevator indicators, possible doomsday machines, clocks – anything that required visual output would be a candidate. Although nixie tubes are now totally out of date, as with many things there is a growing trend to use them again, for cool retro-style, nostalgia and those people who enjoy living in the past.

How nixie tubes work is quite simple, an element is within a vacuum tube full of gas, such as neon. When a high-voltage (~190 volts DC) current flows through the element, it glows. For more information, here is a great explanation. You will note that they are similar to in look but different in design to the vacuum-fluorescent displays, as used in the ice tube clock reviewed a few months previously. The tubes used in this kit are the Soviet model IN-12A:

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The IN-12A tube can display the digits zero to nine, with a nice orange glow.  For the uninitiated, sourcing and making nixie tubes can be quite difficult. Apart from procuring the tubes themselves, you need a suitable power supply and logic ICs that can handle the higher voltage to control the tubes. Thankfully Ogi Lumen have put together a system of kits to make using these nixie tubes simple and interesting. There are three components to the system, the first being the power supply:

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Note that the power supply is preassembled. This supply can generate the necessary 150 to 220 volts DC to energise our nixie tubes. Yes – up to 220 volts! For example:

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However the current required is quite small – one power supply can handle up to twenty-four IN12A nixie tubes. My example in the photograph above is drawing 110~120 milliamps from a 12V DC supply. For those of you assembling these kits, please be careful. It can be easy to physically move the kit about whilst in operation, and touching the live HV pads will hurt a lot. After bumping the HV line on the PCB, my whole left arm went into a spasm and hurt for the time it took to see my doctor. So be careful.

The second item required is the driver kit. This is a board that takes care of the shift-registers and power for two of the nixie tubes. Driver kits can be slotted together to form a row of nixie tubes. The third and final item is the nixie duo kit. This contains two IN-12A tubes, matching sockets and a PCB to muont them. This PCB then slots into the driver kit PCB. You can buy the driver and duo kit as a set for a discount.

From a hardware perspective, assembling the kits is relatively simple. There isn’t any tricky soldering or SMD to worry about, however you will need a lot of solder. The contents of the duo and driver kits are as follows:

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Before you start soldering, please download and take note of the instructional .pdf files available for the duo and driver board kits. Assembling the driver kit (on the right) is very straight forward. However – please read the instructions! An interesting part of note is the K155ИД1IC:

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This is the Russian equivalent of the 74141. This is a BCD-decimal decoder IC that can handle the high voltages required for nixie tubes. When soldering the resistors, take care with R2 – it will need to be positioned horizontally so as to not rub against the duo board:

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When it is time to assemble the duo board, you will need time and patience. At a first glance, one would imagine that the sockets drop into the PCB, and the nixie tubes will happily be seated into the sockets. This is not so, don’t solder in the sockets first! The pins on the bottom of the socket also form part of the socket for the tube legs – which can alter the positioning of the socket legs. Make sure you have the socket with pin 1 at the top of the PCB. After some trial and error, the best way to insert the tubes is to first partially place the sockets into the PCB:

p1080880

… then fully insert the tubes into their sockets. Make sure the tube is the right way up – check that the digit 3 in the tube is the right way up. Then push the whole lot into the PCB. At this point you should check to make sure the sockets are in line with each other:

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(Notice how thick the PCB is…) At which point you can solder them in, followed by the row of connector pins:

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By this stage you will need some fresh air from all that soldering. The PCB holes for the socket pins really take a lot. Now you can connect the power supply to the driver board and give the tubes a test-toast:

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All the tubes should have their elements glowing. This is a good start. The next step is to connect the appropriate microcontroller and start displaying. As noted in the instructions, the 74141 BCD-decimal ICs are controlled by standard 74HC595 shift-register ICs, so your microcontroller needs to send out a data, clock and latch line. My following examples have been created using the Ardiuno system and a compatible board.

The first example is a method of displaying integers. It uses the Nixie library which you can download here.

That was just an arbitrary demonstration to get some numbers displayed. Here is a short video clip of it in action:

Now for another, more useful example. By using a DS1307 real-time clock IC with the Arduino, we can make a nice clock that displays the time and date. For more information on using the DS1307 with Arduino, please visit this tutorial. You can download the example nixie clock .pde file from here. And finally, here is the clock in action:

The problem with these tubes is that you will never have enough. Already I have thought of a few things to make that require a lot more tubes, so in the next month or so stay tuned to tronixstuff.com as there will be more projects with these kits.

In conclusion, this was a great kit and anyone looking to use some numerical nixie tubes will do very well with the Ogi Lumen products. Furthermore the designs are released under Creative Commons by-sa-nc, and the files are available to download from the product pages. And finally, it is a lot of fun – people will generally ask you about the tubes as they may have never seen them before.

Remember, if you have any questions about these modules please contact Ogi Lumen via their website. Higher resolution images available on flickr.

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.

[Note – the kit assembled in this article was received from Ogi Lumen for review purposes]

Posted in arduino, kit review, learning electronics, nixie, ogilumenComments (11)


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