Hi;
Can anyone point me to a tutorial or the like to help make a simple robot from a single motor RC car. I know two motors are more popular and would be better but at the moment I only have 1 x RC car with a single motor and I gues a small actuator for the steering.
My thoughts were that I could control the drive motor and the actuator for the steering using a compatible arduino nano like this:
Search this site for rc car arduino
You will find a number of people have done exactly what you are asking.
Looking into this a bit
Looking into this a bit more, will I need a motor driver board for the Arduino Nano or can I use the RC Cars own motor driver board?
Or buy a cheap l9910 breakout board
There are some cheap boards with motor driver chips, so you can link any arduino. Of course hijacking the existing motor board give bonus experience!
Ok so I spent an hour or so
Ok so I spent an hour or so in the garage and spent some time taking this RC Car apart.
On the main (only) PCB there are two IC’s one of which is an SDRX2BD, there is not a lot of info about this IC but I did manage to find a post on a Robotics site giving the Pin Outs and then managed to find the data sheet (I think).
Here’s the data sheet fir the SDRX2BDS:
https://www.dropbox.com/s/go5e1c6nlnhtq2z/SDRX2BD_Data_Sheetdatasheet.pdf?dl=0
The Pin Outs appear to be ideal to the Realtek IC in the Arduino controlled RC Car Bot show here on LMR posted by nintwala.
So my thoughts are that I could do exactly what nintwala has done and send HIGH signals direct to the RX I/C using either an Arduino Nano / Uno or a Basic Stamp 2 that I have in another Robot. Would I need to remove anything from the RC Car controller board?
I’ll keep the existing power for the motors (4 X AA) and power the Microprocessor with its own supply.
Here are some pics of the cars PCB:
P3 connects to 2 x Bi Colour LEDs, P2 is the Steering Motor, P1 is the Drive Motor and P4 is spare.
The SDRX2BDS is the IC at the top.
I also got through the post one of these Ultrasonic Sensors which I was going to use for collision avoidance, I can't believe how inexpensive these are nowadays.
Your proposal should work.
I have read about one person mentioning their RX2 chip warmed up while someone was driving the pins externally; just something to look for. You should also be aware that as was pointed out before the steering motor is likely a DC motor with a spring to center it. Your steering will be “bang-bang”. You will likely only have full left, center, and full right with no in between. You may get some in between by pulsing the motor in the direction you want, but, you will surely wear on that motor. You could always swap it for a servo as another memeber here did with their repurposed RC toy.
**Steering **
Yeh, when I took the the steering apart and found that it was a standard DC motor that when power is applied without being attached to the steering it spins continuously, this would cause a lot of power drain if the steering was left on, something to consider seriously.
If I keep the DC motor i’ll have to work out how long to issue a left or right trun to hit full lock.
Thanks
