PBP projects for R/C models

[malc-c]

To be honest I would never use the same power pack to power the electronics. Even when using electric helicopters I would use an RC pack for the receiver, with the main flight pack used just for driving the main motor. 4 x 1.2v Nicads provides a decent supply for the electronics

[Kenjones1935]

I too initially designed with two battery packs. One for the servos and the other for the electronics. My problem is one of packaging. Getting a cheap kit that fits easily into a HPI Racing Touring Car Ready to Race package is way beyond my expertise. Why the HPI car? That is what I have. Also Ten80 Education

( Which I know as http://www.ten80eduction.com)

specializes in using radio control cars for curriculum and lesson plans supporting STEM in our schools. One of that company's sponsors is HPI Racing. I hope to get ten80 support. One battery is much easier to mount than two.

I took my car again for a run. It is using the "there is nothing within four feet of me, I must be under radio control" toggling algorithm. I liked the effect. It is important that the room have lots of room. Clearly a gymnasium fits that criteria. Adding the photoresistor system is more than I can deal with at this time.

Two projects are looming. 1. Get help and advice on packaging (surface mount prototyping). 2. Create a video story board then shoot a video showing what I have built, why I built it, how to modify the code and why I think middle school students will jump to learn.

I discovered a neat trick today. The studio has a small push cart with roller skate sized wheels. I put my car on the cart (back end facing me - it has no sonar sensor) and pushed it around the maze. I could easily see the reaction of the car to each position. It made very clear that the problems are speed, momentum and reaction time.

Ken

[Kenjones1935]

Today after watching my car behave very differently when actually running on the floor as compared with its wheels spinning freely on a pedestal I decided that I need to install the second battery pack and its 5volt regulator. Nuts, more micro-soldering.

Ken

[Kenjones1935]

Please suggest your ideas on competitions that could be implemented with my PIC and/or RC controlled hobby level car. Right now all it does is go through a left turning maze. Programming for both right and left turns is the most obvious extension.

What if I added different sensors and maybe some kind of emitter. I am thinking of a game of tag. Somehow the rest of the cars in the group would need to know which car is "IT".

What fun could be had with a group of these cars?

Ken

[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

[flipper_md]

on the power topic, I've read that most current electric R/C plane systems uses a BEC to run all servos/receiver from the main battery pack(Mostly LiPo these days).
BEC usually have a safety function that will choke power to the motor, but keep servos alive in case that you are running out of juice.

[Kenjones1935]

I'll catch you all up a bit.

I have changed tack.

I am trying to go from a hobby level car with PWM controls to a toy level car most of which have simple DC wheel and servo controls. The purpose is to reduce the cost of kitting for school students. In addition to reducing the cost, DC control of two wheel drive makes it easier to implement a sporty racing-like skid steering.

I purchased (at K-MART) two 1/10 scale toy cars on sale each for $25.95. Their original prices were $50. The 1/10 size gives me more room for adding microchip electronics. The wheels and the steering if driven simply by DC with reversing current are easily controlled using DPDT relays controlled via current drivers by my PIC .

WRONG! The steering servo contains both a DC motor and an angle measuring device which is read by the electronics that comes with the car. A total of six wires go to this servo. Where can I read how this works? Should I just go back to the store and buy 'proper' toy level cars? Your suggestions would be greatly appreciated.

Thank you thank you for the oscilloscope. Without it I would not have the faintest.

Ken

[mackrackit]

A total of six wires go to this servo.

That sounds like a stepper.
A picture of the setup might help...