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I am an Electronic engineer and had quite a lot of success at work using Ardunio's to build the test systems at work. I thought it would be fun to build a rep(st)rap over the winter 11/12 with my son.

Last year I built a Cruzbike conversion kit (see currystomper on the forum)- so hopefully I will get to the end of this project over the winter!!.

I like the look of the Wolfstrap and so may start at that point.

...more later.

BedHead Foley

(An idea to be left in user space until I get some results - don't hold you breath for progress)

Having spent some time looking around the site, I think I'm going to start with a Wolfstrap, I like the idea of using a threaded rod to drive the axis's. However I see at the bottom of the page that stepper are far to slow for this. (Also they generate a system that is too accurate ie too many steps per mm.)

So you need to you choose course (cheap!!) 7.5 Deg steppers, hopefully this will be quick enough: Maybe its been done before see

So here is my mad idea (foley!!) a brushless DC motor is actually a course stepper motor, when used with a threaded rod system this may give quite a nice drive system, so my plan is to made a single axis system to see if this is a mad idea or not. I can test out its max hold, repeatability over time and its max force.

If this works out it may reduce system costs quite a lot - maybe it holds out the possiblity of a system making some of its own drive systems too..

A bunch of DC Brushless Motor (BLDC motor) Links/thoughts :

Wikipedia :- BLDC motors

Lots of choice here

interesting view of a simple BLDC

Ha Ha - looks like it may work

Half bridge motor controller TLE4207G 1 1/2 needed per motor 2 or 3 $ each!!

BLDC has three wires therefore must be a Unipolar motor - no its a 3 wire bipolar.

driver chips L293D

Three phase motor driver L6234 STMICROELECTRONICS

Brought a motor and its needing 1.5A @ 0.5 when it is stationary - so I'm going to explore the course stepper motor route first

Wooden Eiffel

Here is a Gridbeam prototype wooden Eiffel

Wood Eiffel proto1.jpg

.... still not happy with the 3 unit long cross beam should this go above the main cross beam out of the way...

Note not all connections in place

Interesting Links






driver schematic for idea s...[[]]

Fast screw thread video [[1]] needs course stepper motor to get the speed up, but as the gear ratio is high a low cost stepper should be OK (My stepper were ~5UKP new from ebay to see if I can replicate this preformance.

Using SDS drill bit as a course lead screw may be a final piece of the puzzle - why didn't I find this one!! < $10 for a lead screw

Nice CNC Router [[2]]

Easy mill




My Dad: an excellent Carpenter and wooden tool maker.

Leah Buechley MIT: High low tech [[3]]