Reversing a RC toy!!
Posted by Beyond
I was in despair shock when I read that in China, there are greater number of hardware incubators than software ones. But yes, it appears accordingly too. We see the whole fucking market covered with the chinese toys. Those RC controlled cars and even flying helicopter toys.!!!!
Mannn, I get so frustrated.
How on Earth they are making the stuff so cheap!!!
Again, its all a matter of production and playing dirty on quantity.
Nevertheless, recently the kids in our house bought a RC toy and yes I got a look of it. You know how a hardware engineer looks the objects…the Nerdy dirty way.. but since it was working so I am not supposed to touch it. In my home, it is official that I cannot touch any working piece of electronic Object.
Anyways, the day came and it finally got damaged, obviously children damage every other toy of theirs!!! YEAHHHHHHHHHHHHH! i am getting a chance to get my hands with that.
So, now the ball was in my court. Without any delay, the children come to me and asked their electronic shop wala bhaiya to repair the car. I was not at all in mood to actually repair that shit because Chinese technology is not easy to debug or Reverse, this is what I have already assumed because of my past experiences. Anyways, I accepted it and added to the crap collection.
Last morning, I wake up, was in a bad mood, because I had a bad dream, that reminded me of someone 😛 So, I autonomously picked that toy out of the collection and started Reversing it.
Reversing the toy Car:
It actually contained nothing, except of the two motors; rear and the front with all the plastic assembly and a small pcb circuit at the back with a few leds. The PCB there was containing only one IC!!!!! oops! I have always used a bot with a controller and a isolater with a motor driver at least and this crap was having only one IC. Then I guessed, yeah these china people may have integrated the work in one IC to reduce the further costing.
The problem was that the RC car was not working. So the error can be on transmitter side or the reciever side or both! I started with the reciever side because Reciever side is generally complex and easy to get damaged because of the larger circuitury. The IC there has written blurred RX-2B. It was like a divine gift while reversing any hardware. Mannn, you gotta be kiding.. I got the IC name!!! A quick google gave me the IC datasheet, so it was quite clear that I got the pin diagram. Checking the voltage and ground at pins was of no result, quite bad!! This simply meant that either the IC got damaged or the supply was faulty. Supply was Ok, I know it, the cells were working. The IC was not getting powered up. So I simply re-traced the path of the power line and got a few transistors and capacitors.
Transistors– I really know a little of those. Very basic level of knowledge. I only know that these perform two functions : switching and amplifying(in modes). Ughh, how can people deal with so heavy set of configurations and formulas associated. I never find a need to understand them so I didn;t studied, skipped even in my exams, though I got passed.
And thats where the problem was, one of the transistor driving the power line was suspicious, because the transistor’s two legs were short circuited. !!! I really dont know why, but this is what continuity showed me up. So, it was simple from then. I checked out the motors and lights instantly by giving direct supply and voila! those were working. So, I got the problem the transistor was damaged! I desoldered the transistor and directly gave the power supply to the IC pin 13 of RX IC. The H bridge is actually formed there by the complmentary transistor pair I guess, because they were not using the motor driver and obviously the IC was not able to support that much amount of current so the basics rule again and saved the cost.
About Beyondan electronics hobbyst, 8 bit microcontroller(8051/AVR/Arduino) programmer, Linux lover, in love with Embedded Linux systems ... TGL: just push it "BEYOND THE LIMITS"..
Posted on October 20, 2012, in 8-Bit Embedded World, Embedded Systems and tagged car, chinese toys, complementary pair, hardware engineer, motor driver, plastic assembly, rc toy, remote controlled, rx 2b, toy, transitos, tx 2b. Bookmark the permalink. Leave a comment.