PBP projects for R/C models

[Kenjones1935]

I have installed a second battery pack -- four AA batteries now power the PIC and all the electronics except the radio receiver. The original 7.2 volt NiCad battery power only the servo, the electronic speed control and the radio receiver.

The inconsistent behavior in autonomous control may have been because of noise, but then it could be because of slow reaction time relative to speed travel. Not sure yet.

I need suggestions on how to prototype this package. There appears to be shops that offer short run PC cards. PCB-POOL advertises in the SERVO magazine. You all have any preferences?

Ken

[mackrackit]

I have used these folks.
http://www.expresspcb.com/
Only thing I do not like is you have to use there software. But very happy with the three boards for $51.00. Nice work and quick turn-around.

[Kenjones1935]

Mucho frustrations followed by some successes. The PC board proto challenge is beyond me for now. Created instead a car that toggles itself between radio and PIC control without using a third radio channel and negotiates a maze that includes both right and left turns.

The auto toggle is a function of the car being out in the clear - not in or too near the cardboard maze. The right and left turns were pretty obvious after numerous stupidities.

I hope to post a video next week.

Thanks again for all your support.

Ken

[Kenjones1935]

I think the code is pretty solid. Now the problem is response time, size of maze passageways and RC car speed. A fraction of a second does not seem very long when the car is up on blocks, but it is enough time at speed to crash into a far wall when it should have detected a turning opportunity and done its thing.

I think I need:
1. Techniques using PICBASIC Pro for recording data in memory that can be read back into my PC for analysis. How do I do this? I have not the faintest idea what app to use.

[mackrackit]

This is a tough one.

If the trouble is speed and timing then using more MCU cycles might make it worse.

You can look at writing data to the on-board EEPROM.
http://melabs.com/resources/samples/pbp/eeword.htm

[ardhuru]

I think I need:
1. Techniques using PICBASIC Pro for recording data in memory that can be read back into my PC for analysis. How do I do this? I have not the faintest idea what app to use.

This thread might help:

http://www.picbasic.co.uk/forum/arch...p/t-13317.html

Regards,

Anand

[Kenjones1935]

Thanks for your attention and replies.

I think the PIC is plenty fast enough. I think the SFR05's are responding quickly enough judging from their flashing LED's. My guesses are either SFR inconsistencies and/or weakness in my jury rigged PWM signal.

The servo and the speed control want PWM pulses at 50 per second. I have not been able to do that with my PIC. I get the pulse width correct, but I can not get the rep rate down to once each 20 millisec.

Ken

[Kenjones1935]

The PIC KIT2 programmer has, at the bottom, reference to EEPROM. It has addresses 00 - FF.

I think that if I use the PBP WRITE command at run time I can store data in the inchip EEPROM space. 00 to FF in size. I can then manually read this out with PIC KIT2 programmer.

Sound correct??

Ken

[ScaleRobotics]

After reading about some of Bruce's cool projects with the 18F2431 series chips, I have been playing around with them for a little while. One thing that caught my eye is that they can do Power Control PWM as low as 19 hertz (while running at 40 mhz). Something you have to bring other chips OSC down to 0.5 mhz to do. This, and a few more of it's features, make it pretty nifty for creating PWM servo output. I mocked up a quick test, and have been able to do about 10bit PWM 1 to 2ms pulses at the proper 50 hertz spacing on 3 pins with the 18F2431. The larger chips of this series can do 4 pin PCPWM. I will post a little code once I get it cleaned up a bit.

[Kenjones1935]

I received a brand new HPI Racing Sprint car. This is the same model which I have been using. It is just the most recent version.

I am having a problem with the new Electronic Speed Control a SC-15. It has some kind of mind of its own. My old code which told my old car where to go is not working with this new ESC.

Do any of you have the contacts to get me the specs on this "SC-15 ESC WITH REVERSE SPORT CONTROL".

Does is have a PIC? Is it programmable? What are its design algorithms?

Ken

[ScaleRobotics]

Since it doesn't have to be exact, you could simplify your code.

Instead of:

Checkpot:
adcin PORTA.0, Potread
write 4, word Potread
select case Potread
case Potread < 36
Forward = 112
case Potread => 36 and Potread < 73
Forward = 113
case Potread => 73 and Potread < 109 
Forward = 114
case Potread =>109 and Potread < 146 
Forward = 115
case Potread => 146 and Potread < 182 
Forward = 116
case Potread => 182 and Potread < 219
Forward = 117
case Potread => 219
Forward = 118
end select
write 2, word Forward

something like:
8 bit ADC:

Checkpot:
adcin PORTA.0, Potread
Potread = Potread/37
Forward = Potread+112

10 bit ADC:

Checkpot:
adcin PORTA.0, Potread
Forward = Potread/147 + 112