PBP projects for R/C models

[Kenjones1935]

I agree with both of you on the size, shape and frequency of standard PWM signals. I have been running my car (an older version of this same HPI Sprint) successfully for the last couple of months. With the exception of frequency my HPWM pulses agree with your specs. I found the correct HPWM commands by trial and error.

This new Transmitter, Receiver, ESC combo is different. Leaving out my PIC for the moment if I on the radio transmitter I give full forward (trigger full back) and suddenly go to full reverse (trigger full forward) the car goes from full forward to stop (neutral in the PWM sense) and stays there until I bring the trigger to neutral for at least two seconds. Then giving it full back will work fine.

Somewhere in the system is protection against slamming the DC motor with reversed polarities. That is good, but when I tried to emulate that system in my code it did not work.

Thank you sooo much for your support and interest. Oh, yes, the electronic speed control wheel driving system is not a classic servo. Steering is. Wheels used to be - in the day - but no longer.

Ken

[ScaleRobotics]

Leaving out my PIC for the moment if I on the radio transmitter I give full forward (trigger full back) and suddenly go to full reverse (trigger full forward) the car goes from full forward to stop (neutral in the PWM sense) and stays there until I bring the trigger to neutral for at least two seconds. Then giving it full back will work fine.

Somewhere in the system is protection against slamming the DC motor with reversed polarities. That is good, but when I tried to emulate that system in my code it did not work.
Ken

Well, that's a completely different problem than what I thought you had. Why not talk to your friends at the R/C store and find out if they know of any controllers that let you go reverse from full forward. If they do, sell the controllers you have on Ebay, and buy the ones you want with the money?

You might also be able to hack the speed controller if it is for a brushed motor. But you run the risk of breaking a $55 speed control. You could also build your own controller for a brushed motor, but easier to find one off the shelf that will do what you want, if it exists.

[Kenjones1935]

I have been successful in attracting some support for my project. Check out
http://www.ten80education.com

They use HPI Sprint cars.
If I can design a 'simple' enough PIC kit to add to the standard HPI product, the schools might get a pretty good deal. My new car was a support gift cost me nothing.

Ken

[malc-c]

This new Transmitter, Receiver, ESC combo is different. Leaving out my PIC for the moment if I on the radio transmitter I give full forward (trigger full back) and suddenly go to full reverse (trigger full forward) the car goes from full forward to stop (neutral in the PWM sense) and stays there until I bring the trigger to neutral for at least two seconds. Then giving it full back will work fine.

Ken

Electronic braking system. - You might be able to go into the programming mode and disable this function.

[malc-c]

Electronic braking system. - You might be able to go into the programming mode and disable this function.

Uhmm maybe that's not an option. I can't see anything on programming the end points on this controller

[Kenjones1935]

OKAY,

I have discovered through the use of my oscilloscope that PAUSE stops the HPWM output pulses. In order to emulate the radio system I want to try giving the ESC two seconds worth of neutral PWM between switches back and forth between forward and reverse. This is a race car. It will not be going backwards very often, but it is necessary sometimes. Looks like I need to figure out how to set a two second interrupt. Hmmmm. NUTS!

Ken

[ScaleRobotics]

I have discovered through the use of my oscilloscope that PAUSE stops the HPWM output pulses.

Hey Ken, welcome back to town.

Do you mind posting some of your code for us to figure out what is going on? The HPWM command, or using the CCP hardware PWM with your own commands should both work independently of your code. I have a 2 second pause that is repeated, but HPWM keeps pumping out pulses the entire time. But if I repeatedly call HPWM and set it using PBP, it can give me some screwy results. Probably better setting the registers directly, like Bruce shows in this example: http://www.picbasic.co.uk/forum/show...1478#post61478

What PIC hardware are you using?

Thanks,

Walter

[Kenjones1935]

Here is the first couple commands of my code. I deliberately start HPWM then PAUSE for four seconds. My oscilloscope shows a flat line for four seconds then springs in PWM action.

I just looked at it again. I am no longer as certain as I was. Once I get into my code it seems to behave as I expect. I'll get back to you all tomorrow.

Thanks, Ken

[Kenjones1935]

The outputs of PORTC.1 and PORTC.2 are high all the time.
Why? In other code snippets PAUSE seems to allow action to continue. I hope you guys see that I am being stupid.

' PORTC.0 'High is R/C.  Low is PIC control
TRISC = %11110000

main:
low portc.0
gosub straightforward
pause 4000
goto main
end

StraightForward:
pwm 1,120,50
pwm 2,120,50
return