Re: [mowbot] A cheap, easy platform

david steinke (dsteink nospam at
Wed, 05 May 1999 07:54:47 -0700

Terry (Cef) Pearson wrote:
> As jeff pointed out. a microprocesesor seems to do the job quite well at
> being an mowbot brain. Although the "Devil may be in the details" as I have
> never put tried to match a microprocesor with the needed other circuits on
> a board. Now that a have a name for the procesor I can put it into a search
> engine and get the details of how to program and wire it up. I I do know
> that with the 555 timer chips, its was about 3 man/weeks of labor to design
> and solder together with wire wrap wire.

Sounds like about 2 hours of programing on a PIC should be able to
emulate the 555's, once you get good at the code.

> Anyway, I will challenge anyone on coming up with an easier, handier
> platform for the mowbot than PVC. The source of PVC comes from 4 inch PVC
> pipe. I put an 18" section of PVC in the oven at 250 degrees for about 10
> minutes. it becomes as flexable as rubber and I cut down the length with a
> knife. I then press the hot PVC between two boards and stand on the
> arrangement. The end result is a sheet of 1/4" PVC 12" x 18". The nice
> thing with using PVC is that wood or sheet metal screws can be used to hold
> things together. Use a pilot hole, half the diameter of the screw, to get
> it started. Its easy to drill and file, simple hand tools can be used. A
> 10 foot pipe 4" in diameter of shedule 40 pvc costs about 10 dollars, US.
> The formed PVC sheet can be used for other parts too: wheels, cutting
> disk and to attach other parts.
> Terry Pearson

PVC is about the cheapist plastic out there. A 4x8' sheet of 1/4" thick
pvc sheet for $40 is the regular price at my local plastic supplier, so
I wouldn't bother to try to flatten PVC pipe. I might try your technique
for moulding shapes though. The only real problem with PVC is that you
cannot let it sit in the sun. UV degrades it.

David Steinke