hello all, I am building a remote control Go kart for my grandson and am having difficulty with speed control, I have built a mechanical throttle with a twist grip and a servo but am not satisfied with the outcome, I have been told I can do it directly from the receiver to the input of the speed controller but have had no luck converting the rc car remote receivers output which I believe is a PPM signal to the 0 to 5 volt hall effect input on the speed controller. I have been told an Arduino can do it but have no experience with them, is is possible? can anyone help an old man put a smile on a little boys face? any help would be greatly appreciated. thank you for taking the time to read my post.
Most Arduinos do not have a DAC for outputting DC voltages. You'll have to run the PWM output through a low-pass filter before passing it into the speed controller.
If you use an every day run-of-the-mill esc ( electronic speed control) the work is already done for you.
Esc's are available for both brushed and brushless motors and will have facility to use in a car.
The latter means centre throttle stick on the transmitter( spring loaded to return there) will be motor off, proportionally up will increase forward speed and down for reverse.
Some will require a dual movement from centre stick to full reverse to enable reverse speed after forward running.
These esc's can be bought on Ebay or whatever for as little as $20 to $30.
I would love to use an ESC in place of the ebike speed controller, but the problem I have found is the voltage, my motor is a 48 volt 750 watt brushless gear reduction motor on a lipo battery pack, which if I understand correctly is a 13s pack, I have not found an ESC that is rated for that voltage. The ESC would also allow for more precise forward/ reverse control without the need for the full stop before pushing the button to go into reverse the ebike speed controller has. if you have any more info on esc's that might help me over this problem it would be greatly appreciated. thank you for taking the time to read my post.
thank you for your response, unfortunately you are talking above my knowledge base, a little more info or a link to where i can learn more about a board or circuit to interface the two units together would be great, even better would be if there was something commercially available to buy, that would be magical.
If you search for "14S ESC" on an EC website such as ebay, you may get what you want.
14S means a battery has 14 cells are connected in series, and can drive 60V maximum.
Because fully charged 14S Li-po battery reach that voltage.
Basically all you would need to do for increased voltage/current handling would be to make up an interface board with (probably) n-type mosfets appropriately sized.
When you said remote control go-kart I assumed a kids toy, not something one sits in.
As for the reverse function, it might be possible to either select one without that feature of disable it.
Another option is search maybe Ebay, they have e-bike speed controllers. Below is just an example.
Here is a complete setup........
thank you for the advice, I wasn't clear on what I already am using, I already am using a speed controller for an ebike/go kart like you suggested with a rc car style receiver controlling a heavy duty servo physically attached to a twist throttle for forward and backwards pulls the brake cable and reverse is controlled by a separate channel from the remote with a battle bot relay module to make a connection for reverse through the ebike speed controller, it works but is not great, too much latency, clunky and unprecise, an esc would replace all i have in use now and give me direct forward/reverse as i would like, but my searches online have not found one that does 13s yet, and the ones that i think might are vague in description and seem very involve with programing and that's a little over my head, that why I was looking into ppm to hall effect adapter to use the controller I have without my Frankenstein servo throttle. but am open to ANY suggestions. thank you again for your help
Stick with the original idea. Poke around google some more, this has been done.
Arduino decode ppm
for example yields
and many more; take a few minutes to see if this helps.
I think you are on a good track.
Receive traditional RC signal. Capture/decode with Arduino. Produce 0-5 volt control voltage with Arduino.
You will need to low pass filter the PWM from the Arduino.
Or, easy and cheap, add a real digital to analog converter to the Arduino.
Some receivers output a PWM signal per channel on multiple outputs. The principle remains the same.
Typical example of where a drawing or two would make a big difference.