PBP projects for R/C models

[Kenjones1935]

I have four USB ports on the back and two on the front of my PC. How do I know into which physical port to plug the cable?

How does HyperTerminal know?

Ken

[ScaleRobotics]

I have four USB ports on the back and two on the front of my PC. How do I know into which physical port to plug the cable?

How does HyperTerminal know?

Ken

I have had equipment not get recognized when it was plugged into the front, so I would try the back.

Then, is any new hardware getting recognized when you plug it in? This is kind of a must have.

What step are we on. New device, or old device?

The only way that hyperterminal will know is if you tell it what com port it is. And the only way You will know, is if you look in Device Manager, and see a new serial port pop up when you plug the UBW32 in. And, the only way this will happen, is if the UBW32 gets recognized as new hardware. Which will only happen if we have the right firmware loaded .... etc... etc...

But I think we are getting closer.

[ScaleRobotics]

Hey Ken,

I have heard you say bang-bang a lot describing the turning control for the car. Are you saying that with the remote control that came with the model car, there is no proportional control of the steering, just full right, straight, and full left? Or is there any in between?

Perhaps you could do some testing to see if a pwm signal to the steering would give you some sort of proportional control?

Is this the same for the throttle? On and off, and no in between? Perhaps you could test that as well.

Without any more info, I don't think you can get more than wild guesses. Some pictures of the steering control, and motor control might help as well.

EDIT: Hot off the press. This news from MeLabs:

melabs now offers multi-seat, educational licensing of PICBASIC PRO for schools. Call for details.

[Kenjones1935]

scalerobotics,

1/10 scale TOY level cars cost about $50. 1/10 scale MODEL level cars start at $200. The TOYs are plastic toys. The MODELs are miniature automobiles.

The TOY cars have only [full on / full off] steering and wheel power controls. Their steering servo has two inputs. Three of the four possible states are used:
[A=7v, B=gnd] ==> steer left
[A=gnd, B=7v] ==> steer right
[A=gnd, B=gnd} ==> steer straight (spring loaded)

The corresponding is true for Forward, Reverse, Brake (due to back EMF) for their DC drive motor.

The TOYs have no differential gears, no drive gears at all, no toe in, no caster, no spring suspension, no dampening and plastic tires. They are inexpensive, fast, lots of fun and colorful. They do a great racing skid turn - just turn the wheel and put the motor in brake state. They are large enough to easily accommodate my solderless PIC kit.

The 1/12 TOYs are considerably slower than the 1/10 size. I have succeeded in making one run smoothly around the room hugging the wall. A bit boring.....

I'm off to the old gym to test my MODEL level with velocity and warning distances now all proportional to the position on one POT. Hopefully now all I need to do is find the correct velocity proportionizing formula for each of the SONAR warning distances which are:
frontclear
frontdanger
stopreversing
desiredtrack
outertrack

Ken

[cncmachineguy]

heres my 2 cents. I think I read somewhere in this thread you are driving the steering/drives with actual relays. First thing to do I think is trade them in for H-bridges. Then you will be able to get much higher switching speeds.

next, see if you can get the steering to become semi proportional or at least slower by pulsing the control. I am guessing it is a solinoid and not a motor for the steering. These take time to move fully, so if you can release the signal before the wheels have turned all the way, it will become at least stepped. the springs will smooth out the signals to make it appear proportional.

Now I am sure you can do the same with the drive. Once you have H-bridges in there, you can PWM it

[Kenjones1935]

cmcmachineguy,

You are correct. My TOYs use DPDT relays (6msec contact. 4msec release - so they say) driven by SN7407's I have been trying to avoid more electronics. I had hoped to have middle school students build the cars using solderless protoboards and to keep the cost down.... I may need to teach-the-teachers first. They did not major in Science, Technology, Engineering or Math in Ed School. Hmmmm.... In Massachusetts that means hooking up with a local college to give a course which teachers take for "professional development points".

I did find that the TOY steering servos are slow to return to zero. A 50milsec kick to the opposite end gets them started. If I could figure a way to control the kick steer, that would be ideal. It is so spectacular.

I am having a difficult time PIC controlling the MODEL car at cruising speed. This is no where near how fast I can make the car go around the track using the R/C, my eyesight and my coordination.

I took it to the gym today with proportional SONAR thresholds implemented. BIG IMPROVEMENT but still it occasionally hit the wall. Don't know why yet......

Thanks again for the interest and support.
Ken

[cncmachineguy]

Any way you can measure the current for the steering? Maybe it isn't real high and you can use 1 of the DIP H-bridge-on-a-chip. The stall current is what we are after here. Then you would still be able to easily proto board it. Leave the relay on the drive motors.

I suspect if you can get the sterring under control, the drive will become less of a problem