Today we look at 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 ofhackedgadgets.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:
Upon turfing out the contents, we find them to be:
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:
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:
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:
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:
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:
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:
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!
In 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.
Anyhow, thank you for reading and I look forward to your comments and so on. Or for further discussion, join our Google Group.
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