TreadBot

[mackrackit]

For S & G 's, maybe throw a couple of thicknesses of aluminum foil between the board and the motors (taped up or coated somehow of course so it doesn't short out) and ground the foil...see what happens... Might help with the EMI if there is any.

And if it doesn't work...at least it'll keep little green aliens from invading your Treadbot with their evil mind control devices!

The aluminum foil will work for aliens but if the problem is a magnetic one you will need something with a high magnetic permeability. Hold a compass near the motors when they are running and see what happens. Use one that you will not care if it gets reverse polarized.

If this is the problem, all you should need is a thin piece of cheap steel (roof flashing) that is a little larger than the board being that the motors are underneath it.

[dragons_fire]

Ive been playing with it a little bit, and if i move the board up about 3", everything works great... thats what makes me think its an interference problem instead of a "low voltage" thing... i would prefer to keep eveything as close as possible, so its not top heavy..

my sidekick still isnt working, so i have been spending most of my time on it, but when i get it going again, this robot should be driving around my house all the time...

[mackrackit]

Ive been playing with it a little bit, and if i move the board up about 3", everything works great... thats what makes me think its an interference problem instead of a "low voltage" thing...

To me that sounds more and more like a magnetic problem. A magnetic field will drop off something like an inverse square, RF does not. (some one will want to correct this) At least if it was RF, it would most likely carry more than 3"

A little info http://www.lessemf.com/guidelines.pdf

[dragons_fire]

so, i added a sheet of "galvanized flashing" between the board and the motors, and i bent some to make a box that fits perfectly over the PLCC socket, and it seems to help.. its still not perfect, but its a whole lot better than it was before. im going to see what i can do to shield it a little better. i also need to ad caps to the other motor, and im going to see what i can do to make some tubular shields to fit over the motors..

i have also noticed that things get worse if i ground all the shields..

i like the way its laid out right now, but i think it might help if i switch the controller and battery boards, so the PIC would be farther away from the motors. it would also lower the centre of gravity, and make the whole robot a little more stable...

i will try to play with it a little more this evening, and maybe add one more sheet under the one i already have, but idont want to raise the board too much, its already top heavy..

[mackrackit]

I forgot to mention that grounding the shields will transfer eddy currents.

You might try bending the sheet metal that is between the board and motors down over the tracks (fenders)?

With out a gauss meter the fields will be difficult to map. A compass can sometimes give you an idea.

This is a gadget I use. http://www.forcefieldmagnets.com/cat...roducts_id=100

[dragons_fire]

when i first started building this, my intention was to put the battery between the 2 motors inside the red fibreglass. because i wanted lots of capacity, and a higher voltage, i added them to the top. so now i have lots of room insid the chassis.

i will probably make tubes to go around the motors, and hopefully that will help.

I might also cast a lead "brick" to fill in the space between them to make it a little more stable on angles, and for more grip. the only problem is that i will lose some endurance because the motors will need to haul more wieght.

ive been working for the last ten days, but i get the next 4 off, and its raining like crazy here, so i should get some time this weekend to play with it a bit more.

After i get the "interference" problem figured out, i will have a video up here of it driving around. i have written the code for it to speed up, drive, sense obsactles, slow down and then turn and drive that way..

[skimask]

when i first started building this, my intention was to put the battery between the 2 motors inside the red fibreglass. because i wanted lots of capacity, and a higher voltage, i added them to the top. so now i have lots of room insid the chassis.
i will probably make tubes to go around the motors, and hopefully that will help.
I might also cast a lead "brick" to fill in the space between them to make it a little more stable on angles, and for more grip. the only problem is that i will lose some endurance because the motors will need to haul more wieght.
ive been working for the last ten days, but i get the next 4 off, and its raining like crazy here, so i should get some time this weekend to play with it a bit more.
After i get the "interference" problem figured out, i will have a video up here of it driving around. i have written the code for it to speed up, drive, sense obsactles, slow down and then turn and drive that way..

It was recently (today) suggested in another thread talking about unused pins and running motors and getting interference, etc., to occassionally reaffirm your TRIS assignments for all the pins you're using.

In other words, every once in awhile, or whenever you can spare a cycle or two, redo all your TRIS's, keep your inputs as inputs, and your outputs as outputs.

It seemed to help this other person's problem with motors, magnetics, etc., and it's only a slight software change.
Might help you too...