Tag Archive | "infra"

Tutorial: Arduino and Infra-red control

Learn how to use Arduino and infra-red remote controls in chapter thirty-two of a series originally titled “Getting Started/Moving Forward with Arduino!” by John Boxall – A tutorial on the Arduino universe. The first chapter is here, the complete series is detailed here.

Updated 10/07/2013

In this article we will look at something different to the usual, and hopefully very interesting and useful – interfacing our Arduino systems with infra-red receivers. Why would we want to do this? To have another method to control our Ardiuno-based systems, using simple infra-red remote controls.

A goal of this article is to make things as easy as possible, so we will not look into the base detail of how things work – instead we will examine how to get things done. If you would like a full explanation of infra-red, perhaps see the page on Wikipedia. The remote controls you use for televisions and so on transmit infra-red beam which is turned on and off at a very high speed – usually 38 kHz, to create bits of serial data which are then interpreted by the receiving unit. As the wavelength of infra-red light is too high for human eyes, we cannot see it. However using a digital camera – we can. Here is a demonstration video of IR codes being sent via a particularly fun kit – the adafruit TV-B-Gone:

Now to get started. You will need a remote control, and a matching IR receiver device. The hardware and library used in this tutorial only  supports NEC, Sony SIRC, Philips RC5, Philips RC6, and raw IR protocols. Or you can purchase a matching set for a good price, such as this example:

irpackage

Or you may already have a spare remote laying around somewhere. I kept this example from my old Sony Trinitron CRT TV after it passed away:

sonyremote1

It will more than suffice for a test remote. Now for a receiver – if you have purchased the remote/receiver set, you have a nice unit that is ready to be wired into your Arduino, and also a great remote that is compact and easy to carry about. To connect your receiver module – as per the PCB labels, connect Vcc to Arduino 5V, GND to Arduino GND, and D (the data line) to Arduino digital pin 11.

Our examples use pin 11, however you can alter that later on. If you are using your own remote control, you will just need a receiver module. These are very cheap, and an ideal unit is the Vishay TSOP4138 (data sheet .pdf). These are available from element-14 and the other usual retail suspects. They are also dead-simple to use. Looking at the following example:

From left to right the pins are data, GND and Vcc (to Arduino +5V). So it can be easily wired into a small breadboard for testing purposes. Once you have your remote and receiver module connected, you need to take care of the software side of things. There is a new library to download and install, download it from here. Please note that library doesn’t work for Arduino Leonardo, Freetronics Leostick, etc with ATmega32U4. Instead, use this library (and skip the modification steps below). Extract the IRremote folder and place into the ..\arduinoxxx\libraries folder. Then restart your Arduino IDE if it was already open.

Using Arduino IDE v1.0 or greater? Open the file “IRRemoteInt.h” in the library folder, and change the line

Then save and close the file, restart the Arduino IDE and you’re set.

With our first example, we will receive the commands from our remote control and display them on the serial monitor:

Open the serial monitor box, point your remote control to the receiver and start pressing away. You should see something like this:

What have we here? Lots of hexadecimal numbers. Did you notice that each button on your remote control resulted in an individual hexadecimal number? I hope so. The number FFFFFFFF means that the button was held down. The remote used was from a yum-cha discount TV. Now I will try again with the Sony remote:

This time, each button press resulted in the same code three times. This is peculiar to Sony IR systems. However nothing to worry about. Looking back at the sketch for example 32.1, the

section is critical – if a code has been received, the code within the if statement is executed. The hexadecimal code is stored in the variable

with which we can treat as any normal hexadecimal number. At this point, press a few buttons on your remote control, and take a note of the matching hexadecimal codes that relate to each button. We will need these codes for the next example…

Now we know how to convert the infra-red magic into numbers, we can create sketches to have our Arduino act on particular commands. As the IR library returns hexadecimal numbers, we can use simple decision functions to take action. In the following example, we use switch…case to examine each inbound code, then execute a function. In this case we have an LCD module connected via I2C, and the sketch is programmed to understand fifteen Sony IR codes. If you don’t have an LCD you could always send the output to the serial monitor. If you are using the DFRobot I2C LCD display, you need to use Arduino v23.

Furthermore you can substitute your own values if not using Sony remote controls. Finally, this sketch has a short loop after the translateIR(); function call which ignores the following two codes – we do this as Sony remotes send the same code three times. Again. you can remove this if necessary. Note that when using hexadecimal numbers in our sketch we preced them with 0x:

And here it is in action:


You might be thinking “why would I want to make things appear on the LCD like that?”. The purpose of the example is to show how to react to various IR commands. You can replace the LCD display functions with other functions of your choosing.

At the start working with infra-red may have seemed to be complex, but with the previous two examples it should be quite simple by now. So there you have it, another useful way to control our Arduino systems. Hopefully you have some ideas on how to make use of this technology. In future articles we will examine creating and sending IR codes from our Arduino. Furthermore, a big thanks to Ken Shirriff for his Arduino library.

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, control, DFR0107, dfrobot, education, infrared, IR, learning electronics, lesson, microcontrollers, remote, tronixstuff, tutorialComments (17)

Kit Review – Alan Parekh’s Infra-Red Jammer

[Updated 17/01/2013]

In this review we examine another kit which goes hand in hand with other mischievous items such as the TV-B-Gone – the Infra-Red Jammer kit by Alan Parekh of hackedgadgets.com. The function of this product is to create infra-red signals that are stronger than those from a normal remote control, thereby rendering it useless. Our jammer sends the signal out using four high-output infra-red LEDs, on the following frequencies: 30, 33, 36, 38, 40 and 56 kHz.

This is controlled by a small MCU that is included in preprogrammed form with the kit, so you don’t need to do it yourself. However, if you are building a jammer from scratch, Alan does allow the download of the hex file to program your own. However, please note that this kit is not an open-source hardware, so you cannot just start knocking out your own. But enough talking, let’s get building!

The kit is packaged in the typical minimalist fashion, the parts inside an anti-static bag:

bagss

Upon turfing out the contents, we find them to be:

contentsss

Unlike most other kit suppliers, I was very happy to see the IC socket included. It probably cost about 10 cents, but it can save someone a whole day of mucking about if they aren’t the best at soldering, and don’t have an electronics store nearby. Furthermore the PCB is solder-masked and silk screened nicely, and is of a decent thickness. Once again – if smaller companies can offer kits with such great PCBs, why cannot larger multi-million dollar outfits like Jaycar offer such great PCBs in their kits? Grrr. Anyway.

The assembly instructions have been compiled into a very neat and tidy book that is downloadable as a .pdf file. It is very clear and easy to follow, great for beginners or enthusiasts alike. So at this point it’s time to get soldering.

At first you need to decide upon the power output strength which is determined by R1 and R2 – for me, it’s all or nothing so I went for the high-power resistors. Thankfully values to use three output levels are included, so you will have some spare resistors at the end. Once those are in, the rest of the assembly is relatively straight forward:

pcbss

What did take me be surprise is the length of the leads on the two electrolytic capacitors – they were very short. This made mounting them difficult:

shortcapsss

However with a little perseverance they went in and stayed put. Although the jammer is activated for thirty seconds by pressing the button as seen in the photo above, there are also two pads on the PCB for another button… so you could, for example, mount the jammer under a lounge or inside an object, and have the button wired remotely. Very good idea:

extraswitchss

They are visible between the diode and the press button. Finally it was time to plug in a 9V battery and start jamming. Interestingly enough the PCB size matches the profile of a typical PP3 9V battery, so if you insulated the PCB with tape or another material, you could mount the PCB onto the battery:

9vsamess

As decided earlier, I chose the highest power output setting by using the low values for R1 and R2. At this point I was curious as to how much current the jammer will draw while operating – which turned out to be 209 mA:

209mass

So bear this in mind if you are going to spend the day jamming up things. You might want to carry a spare battery, or wire a couple up in parallel. But now it was time to get jamming and have some fun. The check of the infra-red LEDs was successful:

operatingss

A test at home showed it knocked out all the IR receivers on my sound and video gear from a distance of around 5 metres. I couldn’t try any further as a wall was in the way, but with the unit set to high power I’m sure it should be good for around fifteen metres at least.

Now when you press the button, the jamming will run for thirty seconds. However you can increase this by buffering up more presses – for example if you press the button three times the jammer will run for ninety seconds. If you were in a trade show, or somewhere you needed to create some mayhem, build a TV-B-Gone and one of these jammers. Turn off the screen then setup your jammer for a couple of minutes. You will drive the presenters positively nuts. Awesome!

Conclusion

This is another fun and inexpensive kit that can be used for hours on end in various situations. It was easy to solder apart from a couple of capacitors, and getting them in wasn’t really a problem once you held them in with some blu-tac. So if you’re looking for a gift for some trouble-makers, or just want to stop people changing the channel during the cricket, this kit is for you. It is available directly from Alan’s website here: http://alan-parekh.com/kits/ and is a steal for less than US$20 delivered.

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.
[Note – this kit was a promotional consideration made available by Alan Parekh]

Posted in infrared, jammer, kit review, product reviewComments (0)


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