R/C Receiver Output to 1 to 4v Signal

I would like to replace a Hall effect throttle for a scooter controller with the output signal from a radio control receiver.
I understand that the Hall Effect Throttle has a 1-4v output to the controller.
I believe the R/C receiver's servo output is a pulse width signal which goes from 1.0msec to 2.0 msec duration at a frequency of 30-40hz. The 1.5msec pulse width is the zero position where the servo would change direction. In my case, I would just want the 1.0-2.0msec pulse to possibly drive a FET to create the 1-4v signal that the controller is looking for. Maybe do something similar to creating an analog output from a PIC PWM output.
I've searched the forum and haven't found anything relevant. Any thoughts would be appreciated.

I think I know how to do it.
What supply voltage(s) do you have available?

I have +12v but I would use a +5v reg.
I've been thinking that doing this without a Pic Micro would be fairly involved, prob need a 556 and above my capability. Might be easier to do the pulsein function from the R/C receiver to a 16F84 and then output the required PWM into an RC network to create the needed 1-4v signal for the controller.

Duplicate post.

jrudd said:

I have +12v but I would use a +5v reg.
I've been thinking that doing this without a Pic Micro would be fairly involved, prob need a 556 and above my capability. Might be easier to do the pulsein function from the R/C receiver to a 16F84 and then output the required PWM into an RC network to create the needed 1-4v signal for the controller.

Click to expand...

I can do it in analog, but it requires a dual op amp, an analog switch (CD4066), a CD4013, a CD40106, 4 bipolar transistors, and a few resistors and capacitors. If you have the skills to do it with a PIC, go for it.
I will say that my circuit does not use PWM, so the response to changes in the servo pulse width are instantaneous. PWM requires a filter, so it has some delay, but if you make the frequency high enough, the filter delay will probably be acceptable for controlling a scooter.
Do you, or did you, work at Micron? I worked with a Jim Rudd there.

Ron,
Thanks for your help. My name is john Ruddock, a retired Mechanical Engineer. I'm not bad at writing code but when it comes to electronic solutions I'm pretty weak. For now I'm going to attached an R/C servo directly to the Hall Effect Throttle and take over control with my transmitter. Its for a backyard train I built for my Grandsons to ride on and its kind of heavy and I think it would be safer for me to have control rather than them. I'll work on the PIC solution on the bench. It might be handy for future ride on toys or robots.
Thanks,
John

Hi John,
One option might be an electronic speed controller (ESC) for a brushed motor, as used by R/C modellers. This outputs a PWM signal which could be converted by a simple smoothing circuit to a proportional voltage.

Another option is here: https://www.electro-tech-online.com/custompdfs/2012/04/102501di.pdf

Scan about half-way down to the article by James Mahoney. A typical servo pulse signal is converted to 1.25 to 2.75V. Changing that curve to make it a bit steeper should be relatively easy.

John

This is interesting and simple if it worked. Some of these low power, brush type speed controllers are pretty cheap. What would be cool is if I could create the 1v and 4v from my +12 source and then power the esc with the 1-4. Hopefully the output would be 1-4(0-100% PWM).

If you use a PWM-type ESC which puts out a 5V signal then this circuit should give you a 1-4V output for a 0%-100% PWM duty cycle.

Thanks for the info