TreadBot

[dragons_fire]

my problem with this board, is that i rushed into it, without fully thinking things through, and doing my research.. now that i have done some research, snd thought about this board more, i feel more confident that its going to work.. im also going to omit the pads in the top that arent being used (pcbexpress automatically makes pads on the top and bottom of holes). i have been thinking about the 90 degree angles all evening (ive been installing IPTV all evening, and even using staples that hold the wires snug can destroy the signal.. wires need to have a certain radius for each corner, and cant be kinked...) so i angled some traces so they have 45 degree bends now..

i will upload another copy of the board later, to see what people think..

if you look closely to the sprockets, some teeth are actually cut out to make clearance for the bolt heads. imworking on changing that design too. i think im going to use only one chain for drive, and make some kind of wheel to support the otehr side. the chains dont stay on well now, because it was almost impossible to make both sprockets line up perfectly... i also want to say, its driven by 2 windshield wiper motors, with 3 x 8.5A 12V sealed Gell cells. one for each motor, and one for the headlights.. we have lots of old coal mines and caves around, so its meant to be able to explore them...

[skimask]

if you look closely to the sprockets, some teeth are actually cut out to make clearance for the bolt heads. imworking on changing that design too. i think im going to use only one chain for drive, and make some kind of wheel to support the otehr side. the chains dont stay on well now, because it was almost impossible to make both sprockets line up perfectly... i also want to say, its driven by 2 windshield wiper motors, with 3 x 8.5A 12V sealed Gell cells. one for each motor, and one for the headlights.. we have lots of old coal mines and caves around, so its meant to be able to explore them...

Maybe spot weld those cleats to the top of the chain links?
And the bigger bot---do I see one (or more) of those cheap Walmart wireless camera's (one of those that transmit direct to channel 3) on your shopping list? I've got one of those...works pretty good with crappy antenna's out to about 200ft with a bit of overvoltage at the TX (11.1v vs 9v, 12v w/3 diodes in series).

[dragons_fire]

never seen wireless cams at walmart.. gonna have to go tomorrow... i already have some wireless cams though, and one of them is a lot more powerful than most of the "consumer" ones.. its great havin a "ham" license...

i tried welding the cleats to the chain, but it wrecked the "bearings" in it, and so the chain couldnt "flex" very well. the bolts work great, i used to have 3/4" ones on every second cleat, and there was no way it would slide then. it had some trouble turning though because of it, and it scratched the driveway pretty good.

so do ineed the cap in on the MCLR to ground? or should i just leave it in??

my chip has a max speed of 40mhz but all i have is 20mhz resonators. most equipment on the board is meant to use serial commands at 2400 to 9600 baud. i would also like to experiment with some mapping. would it be worth it for me to run it higher than 20mhz, or do you think it will be fine?

[skimask]

They're really cheap cams. Resolution isn't all that good, color's a bit off, but they work.

Welding - I didn't think of that. The pins on those chains are probably pretty cheap metal anyways.

MCLR cap - usually, it's there to keep MCLR held off for a split second during power up. The built-in power up timer handles that for 72ms if enabled. And the cap will also help with keeping transient power flux's from tripping MCLR.

40mhz vs. 20mhz - If you've got anything 5-10mhz laying around, try enabling the internal 4XPLL. The board should run at 40mhz, especially since you aren't trying to interface with anything major like static ram or whatever...yet...

[dragons_fire]

i actaully thought about it, there the backup cams arent they?? i have seen them...

we have a wonderful store here called "princess auto", its a surplus store. sprockets were a dollar each, chains were $8 for 6 feet.

it was actually designed as a snow plow, not a lawnmower. we have a driveway big enough for about 6 cars, and its a real pain to shovel it. at no load, the motors run at about 1.4amps each, and when im sitting on it, riding around, it runs at about 3.5 amps each. in a couple minutes, i will upload the new board design, and see what you guys think, then maybe i will make a new one..

[dragons_fire]

heres the board as it is now.. rught below the tilt sensor, i have a resistor, its supposed to be a cap, i just put the wrong symbol, so that has already been fixed..



let me know if you see anything wrong, i will probably start making it soon.. or if you have any opinions on what i should do differently.

[skimask]

let me know if you see anything wrong, i will probably start making it soon.. or if you have any opinions on what i should do differently.

Nothing wrong that I can, but I think I would make another +5v line run from your regulator up the left side of the board to make a complete loop instead of a half a loop. The way you've got it right now, whatever is at the 'end' of your 5v run will probably pick up a lot of noise, and if it draws any sort of load, it'll really put spikes on the run going back towards the PIC. Might mess it up.
Maybe a 'sprinkling' of .1uf cap's across +5v and ground here and there, if you can fit an extras in there, might not be a bad idea, even if they're surface mount and you have to solder them across the traces themselves. I've done that a few times just as a precaution, used 0805 sized, just laid them right there, no marking or anythiing, just added them in...

And I think it looks much better without all those 90 degree angles in there...