28 March 2011
Author: Giorgos LazaridisProduct Review - IR remote Control Jammer
Alan Parekh from Alan?s Electronic Projects, also known from Hacked Gadgets, offered me some goods from his online store, as well as a kit from his Electronic Kits store. This kit is the Infrared Remote Control Jammer, which i made and test it, and finally wrote the following review for this kit.
What is the IR remote control jammer?
In general, an IR remote control jammer is a device that produces non-visual (infrared) light "noise" of specific frequency, in order to confuse IR receivers, and thus disable (jam) their remote controls. An IR R-C jammer does not harm any of the devices. You can imagine an IR jammer as a loudspeaker near you (the IR transmitter) and a friend of yours (IR receiver) that is some 10 meters away. If the loudspeaker is loud enough, then your friend will not understand what you are saying.
Alan's IR R-C jammer does exactly this. It has 4 powerful IR LEDs that are driven with pulses of specific frequency. One excellent feature of this Kit, is that it does not transmit one single frequency. That is because, there are several standardized IR transmitting carrier frequencies, and you can never be sure which frequency your remote control sends. In general, IR remote controls may transmit with 30kHz, 33kHz, 36kHz, 38kHz, 40kHz and 56kHz carrier wave frequency. To avoid conflicts and increase reliability, many remote controls may transmit with more than one frequency, making them more difficult to jam. So, Alan made this kit based on a PIC microcontroller (PIC 12F675), and programmed it to pulse the IR LEDs with all the above frequencies, one after the other. So, first, it sends 145 pulses with 30KHz frequency and pauses for 1mSec, then it sends 145 pulses with 33KHz frequency and pauses for 1mSec and so on. This way, no IR remote control can remain undisturbed from this jammer.
What i received is...
This is what i received from Alan: (as always, click on the pictures to enlarge)
One of the first things that i examine in electronics, is the PCB. I really like seeing quality PCBs with good artwork and nicely aligned solder mask. I hate thin PCBs whenever it is not required. Also, i like to see dense PCBs, with not unoccupied regions, unless of-course this is required due to high-frequency signals or high amps/voltages. The PCB that this kit has is good quality thick (1.6mm) pre-drilled with green solder mask and white silkscreen with the parts arrangement. The dimensions are 46 x 25mm. The rounded corners give a more professional look. I was (happily) surprised to find out that there are extra holes for the battery wires, to go through and release the mechanical stress at the soldering point. This is a feature that i will certainly copy in my future PCB designs! The fact that there are no mounting holes on a PCB always annoys me. This PCB though is planned to be mounted with double-sided adhesive foam tape directly onto the battery box, so it needs of no mounting holes whatsoever. In any case i like seeing mounting holes.
Mounting the kit
To mount the kit i used a temperature-controlled soldering iron, pliers and wire cutter. I followed the instructions line by line and measured the time needed to solder all the parts on the PCB. It took me about half an hour to finish.
Despite the fact that the PCB is double-sided, the soldering job was very easy. I used a temperature-controlled soldering iron, but a simple 20-22 watts soldering iron will do just fine. The pads of the parts are not too big to "consume" a lot of solder, and the holes have the correct diameter for each part. The solder flows with ease from layer to layer making the soldering job a piece of cake.
Instead of a simple 9 Volts battery clip, the kit came with a 9V battery box. The box has inside the battery clip and it has also a slot for a small sliding switch. The PCB is fixed on this battery box with 2 pieces of double side adhesive foam stickers, which are included in the kit. This is the part that i did not like that much for several reasons. I would prefer a small project box to fit the battery and the PCB inside, rather than this battery box.
Respect to creativity
I decided to write a separated paragraph for this feature. This is the first time that i see a kit with future expansion ports! If you see the circuit schematic, you will see that there are 2 ports of the PIC not used, GP0 and GP3. Usually, in such occasions, these pins are left completely unconnected, something that i hate. In my designs, when i have unconnected pins, i usually put solder pads, so that if i need to use them one day (for some reason), i can easily solder a wire or a pin. In this kit, there are 2 pads, TP1 and TP2 just for this reason. They do nothing more than providing a way to use these unused PIC pins however you like. In addition, there are also pads TP3 and TP4 from which you can provide 5V regulated power!
This costs absolutely nothing to the one who designed the kit, but it proves that he or she respects the creativity of the end user.
Does it work?
Absolutely! I tested the kit with several different TV sets, with 3 different DVD players and with a CD player with amplifier. The kit blocked all the above mentioned devices with success. Also, i have to mention that it is very powerful. It can block the signal even when the remote control is much closer to the receiver than the kit itself. Another think that i liked is that the kit comes with 3 different resistor sets: One for high power, one for medium and one for low power. I used the medium power set, and it is enough to block the remote controls in a medium room (about 30 mt2).
I measured the current consumption of the kit when it operates, and it is about 92 mA, which is normal considering that there are 2 sets of LEDs with a 220 ohm resistor each set. One thing that i did not like at all, is the power consumption when the kit is not working. It draws about 0.6 mAmps or more. I am sure that the circuit can be tweaked to draw less than 20 micros when not used, and that would radically extend the battery lifespan (0.6mAmps = 600 micros).
What the oscilloscope says...
One more last test, maybe the hardest: The oscilloscope will reveal if the kit does what it promises, if all 6 frequencies are transmitted by the LEDs. It was not very easy to separate them, but finally i managed to see all of the 6 frequencies:
So, yes, it does what it promises.
Does it really worth its weight?
The current price of the Kit (28 March 2011) which you can get from here is almost $19. Considering the PCB and the battery box, the kit is not overpriced at all. If you prefer doing it yourself from a scratch, Alan provides everything you need, the circuit schematic, the PCB layers and the PIC code as well (code and hex file). But if you do not have a way to manufacture a PCB and program a PIC, but you do want a TV remote control jammer, then this kit is a fair deal.
What i did like
What i did NOT like
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