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My apologies if this is in the wrong section, seems general enough, hope someone can lend a hand. Ive lurked for a couple weeks now inbetween work and hobby time, ive recently got into the micro controller world and have ran into a stumbling block that i my google skills have failed to help with.
I have a couple projects in mind, but after going through the 'beginner' lessons i got to a point of trying something new. Ive coded an Android app that talks over the inter webs to a server script that serially communicates with the board that currently has lahzers representing the f/b/l/r controls. Thats all fine and dandy, my problem lies on my next step. I have a cheap R/C i purchased in hopes to control first the transmitter then ill wirelessly  build a bot as my next goal. The thing is, the transmitter is nothing like ive found in any tutorials ive came across, the hard part is.. there is no visible circuts on the back. im unsure how to send my signal from the arduino controlled board to the transmitter. The only thing ive successfully done is bridge the buttons to generate the signal.

Im already in the plans of finding a replacement R/C that will be a bit better, but for the time being im wondering if its even possible to pass a signal to this board, let alone solder anything to it to have a 'permanent' attachment to the receiver. 

Im a bit of a newb in this sense, i have done very little circuitry work, im currently in the software development field. I find this stuff facinating and would love to expand these new skills further to something more useful.
Any help is appreciated, or if needing more info please let me know!!
Thank you!




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the hard part is.. there is no visible circuts on the back
That is because the board uses surface-mount components, which means the actual circuit is on the front.
Oh, and it might be advisable to not use 8 Mpx pictures on the web. They take time to load and are difficult to look at on computer screens without manually sclaing them.
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Alrighty, I posted from phone and let that big for detail, I've seen other with same size photo never seen a complaint, loads fine for me, I will keep image size in mind. On the other note, thank you, I didn't realize there was a surfAce mount board, now to figure how to solder the thing. Still not sure how to figure what   kinda signal to send it though. I'm going to get multimeter today and start poking around
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Looks each of the four control buttons ground a pin on the chip. 1=Left, 4=Forward, 5=Back, 14=Right?
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Correct, thats what i originally thought, but when trying to send a digital signal both high and low i dont get any results. it was odd, if i plugged two wires into arduino one for pin and other for hot or gnd and touch them respectively to the pins and to hot/gnd i would get a signal, even if the second wire was connected to another pin on the arduino. I know im not understanding this properly, which is why im researching, but so far i have failed to answer my questions. If you have any other id advice id gladly take it!
Thank you guys for the replies!
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Alright - this is very interesting...

First off, a2hill - I'm going to give you a link ref that will probably help you:

http://www.et.byu.edu/~bmazzeo/LTR/tech.phtml

Notice that the receiver chip in that discussion is a "R288" - while on your transmitter, it is a "T288" - I am pretty certain (and you'll note that I contributed to helping the instructor at the above link) that these are re-badged (house numbered, in other words) TX2/RX2 remote controller ICs - you're images pretty much confirms it.

Now - if you download the IC datasheet (from Realtek) the instructor provides a link for - you find the pinout of the chips on the first page; notice that all of the connections on your controller seem to be -backwards- (and noted by johnwasser) from the datasheet provided by the manufacturer! Not that this really matters, but I wouldn't be surprised if this wasn't some strange "obfuscation" done by New Bright to further confuse others.

Also note that you don't need to have the Arduino tied to the remote controller (unless you need to do this for some reason); you can put the Arduino right on board the R/C car, and tie into the output pins of the receiver chip (actually, you would want to eventually remove the receiver chip from the board, or at least install a switch between it's VDD pin and the power supply - so you can leave it off, and it won't get any "stray" signals).

Since these pins are "active low" pins, the way you want to control the TX2, is to hook the GND of the Arduino to the GND of the chip (or convenient ground on the PCB), then hook a digital pin for each function to the pin on the TX2 chip. To program for it, enable the internal pull-up resistors on the Arduino for each pin, then write a LOW to the pin to activate the function, and HIGH to the pin to disable the function.

On the receiver side of things, the RX2 pins are "active high" - so when active, they output 5V (HIGH) TTL digital - so you would just supply the same to control the car's circuitry (note: this assumes the car is using at least a 5V or higher supply - the TX2/RX2 has a voltage range of 2.4V - 5.0V - so if it is a smaller car or something using lower 3.3V outputs, you might want to check the pin outputs first with a multimeter, and use level converters on the outputs if necessary).

Good luck! smiley
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Alright - this is very interesting...

First off, a2hill - I'm going to give you a link ref that will probably help you:

http://www.et.byu.edu/~bmazzeo/LTR/tech.phtml


This is awesome information cr0sh, could you suggest any more online resources that give information on hacking toy R/C cars?
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Alright - this is very interesting...

First off, a2hill - I'm going to give you a link ref that will probably help you:

http://www.et.byu.edu/~bmazzeo/LTR/tech.phtml


This is awesome information cr0sh, could you suggest any more online resources that give information on hacking toy R/C cars?

You have been following this thread, I take it?

http://arduino.cc/forum/index.php/topic,86883.0.html

Not that it imparts much more knowledge; but it may help. Basically, if your car uses the RX2/TX2 chipset, it can be fairly easy to hack it to control the car with the Arduino (note that intercepting the signal sent by the transmitter, via the RX2 (to pin 3) is going to be a tougher challenge, but probably doable with the right tools - most especially you would want a good oscilloscope; a DSO would be preferred). If your car uses something else, and you can't find a datasheet for it (though most cheap R/C toy cars today do use the aforementioned chipset), you need to trace the motor/actuator leads back to the PCB, and trace out the h-bridge or other driver circuit being used, until you get to the current limit resistors; at this point you would want to measure the voltages involved, and use ohms law with the resistance to determine the current, and change what you need at that point to suit the Arduino. Hacking hobbyist R/C cars is a different beast altogether; if you are just trying to control the vehicle, that's easy (use the servo library); if you are trying to interpret the R/C signals controlling the servos/ESC - that's a different matter (though people have done this, too).
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Alrighty, I posted from phone and let that big for detail, I've seen other with same size photo never seen a complaint, loads fine for me, I will keep image size in mind. On the other note, thank you, I didn't realize there was a surfAce mount board, now to figure how to solder the thing. Still not sure how to figure what   kinda signal to send it though. I'm going to get multimeter today and start poking around

yea I am on a 1280x1024 screen, I dont feel like scrolling around big ass pictures with the explanation 4/5ths off screen

can you hack it, dunno maybe? kind of doubt it though
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