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[on:]

Hello Everyone. My wife thinks i have gone crazy after finding out about arduino about 2 weeks ago.
Since then i have been tinkering with my rc car and its tx/rx. Sleepless days, sleepless nights...dreams of -255 + 255..pulsein..yada yada.

This is what i intend to do:
1. A cheapo RC Car .... get rid of its front steering motor and stick a servo into it. The rear motor which drives forward/backward stays in the car.

2. The car is to be controlled by a Futaba RX and TX ( images attached )

I know that many have done it the other way by using the existing RC car's onboard chip , soldering some wires , and getting to control the car using the arduino but i would like to do up a clean system.



Futaba TX --- > Futaba RX ------> arduino + motor shield -------> RC CAR




What i have done so far
1. I have managed to understand a little on pulsein values. I wired the rx to the motorshield, turned on my TX and moved the steering and accelarator and here is what i got.

Steering on Channel 1
Left        Centre       Right
1128        1481         1868

Accelerator on Channel 2
Forward       Centre       Reverse
1115             1590         1965

Armed with these values, i have gone on a hunt for a arduino code that i can use and modify. One good code that i have been cracking my head on is at
http://www.sparkfun.com/tutorials/348
The code makes use of 2 motors and not any servo. This is where i am stuck with. Since i have no background on any C++ i have no idea how to rewrite the code with a servo plugged in. I hope someone here is able to assist me in this or point me to a similiar code that i could be looking for.

Another burning question is regarding the motorshield that i am using. Its a 1A DFrobot shield. In its specs, it only mentions that it is able to run 2 motors. I dont see any servos in its specs. Does that mean that i will need to get another motorshield that comes with a servo connector? Please advice.

I will be back with more pictures when i progress on. Thank you all for all your support.

[Reply #1 on:]

Does that mean that i will need to get another motorshield that comes with a servo connector?

No. You can control a servo directly from the arduino using the supplied servo library- you just need to connect up the control wire and provide power and common ground to the servo. Don't try to power the servo directly from the arduino, it's marginal at best.

[Reply #2 on:]

Hi Wildbill, thanks for the reply. Am working on integrating the servo and motor on the motorshield now. Any help on the Futaba TX n RX would be great. thanks

[Reply #3 on:]

Am working on integrating the servo and motor on the motorshield now.

Note that the Servo library clashes with some types of motor shield because it disables PWM output on pins 9 and 10, which motor shields often use for speed control.

[Reply #4 on:]

Can someone enlighten me about this diagram? I cant figure out why his signal cable from the receiver falls short and is not connected to the arduino. Why do i see channel 1 and channel 2 and followed by a rc car receiver? How many receivers could he be possibly using?
I am also puzzled on how he is controlling the car, using a RC car transmitter or via his computer?
I am a newbie
Here is his full link
http://jeffsinventions.com/?p=784#more-784

[Reply #5 on:]

Can someone enlighten me about this diagram? I cant figure out why his signal cable from the receiver falls short and is not connected to the arduino. Why do i see channel 1 and channel 2 and followed by a rc car receiver?

Looks to me as if that shows something that started out as a conventional RC system. The servo control signals output from the receiver are no longer connected, but the battery connections have been retained to power the servos. The control signal now comes from the Arduino instead. The designer has used a resister pair as a voltage divider to drop the servo control signal from the Arduino down to about 3V. I'm not sure why. This does not do anything like what you're trying to do.

Back to your original question - you seem to be using your Arduino as an electronic speed control. It would be much cheaper and easier just to buy an electronic speed control, or a mechanical (servo operated) speed control. Nothing wrong with making your own for the fun of it, just wanted to check that you knew there was an easier way.