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Page history last edited by Nick Peters 14 years, 9 months ago




  • Adam Ray
  • Nick Peters


Drawbot info: 


the bipolar stepper motor circuit


Required Kit

2x stepper motors 

2x 1K resistors

L239D dual H-bridge chip

2x NPN transistors.

External power supply

ummm.... a pen and other hardware....

Comments (14)

Nick Peters said

at 8:07 am on May 13, 2009

I've ordered some 12v stepper motors (+appropriate power supply), an h-bridge and some more transistors. They should arrive by this weekend so I'm hoping to check that I've bought the right things.

thom said

at 8:57 am on May 13, 2009

I've got most of the bits and have been working on it over the last few weeks, I think it's going to be a bit smaller than the as220 one, and I want to get it to be able to lift the pen too.

Nick Peters said

at 9:54 am on May 13, 2009

So what state are you hoping to have it in by the 23rd? I've bought the kit but it's a good opportunity for me to get some and wire up a motor driver board (which I've not done before) but I'm not sure whether Adam was hoping to build from scratch on the day - I don't even really know how feasible that is if you've spent weeks working on it.

Lifting the pen would be very cool - I'm really interested in how you plan to do that part.

thom said

at 10:13 am on May 13, 2009

Building totally from scratch on the day is always a challenge, its best to at least prototype some of the unknown/grey areas first, even if you don't get it fully working.

The plan for lifting the pen involves a mini servo with a little armature and a teflon foot from the bottom of a mouse, the armature simply pushes the pen off the surface, not worked it all out yet though. Also want to work on some interesting ways to control it, was thinking of using a graphics tablet so you can draw freehand and it gets scaled up. Or perhaps use an edge finding algo to take live images from a camera and draw them up.

Brian Degger said

at 10:36 am on May 13, 2009

you can use processing to do some edge finding, or a wii controller and a uv pen (ideas here http://hackawii.com/wii-spray/)

thom said

at 12:26 pm on May 14, 2009

I'm gonna shelve my drawbot, not going to have time to do what I wanted before the event. Happy to help out on your project though, I have a bunch of L293D ICs, could possibly do a bit of work on the pen lift mechanism, some other things to source would be reels/spindles for the motors and some low-elasticity fishing line (will make it more accurate)

Nick Peters said

at 4:03 pm on May 18, 2009

Well I've not managed to source any reels/spindles and am starting to realise how unlikely I am to get the chance this week. Having also managed to fry my arduino last night it's all going rather splendidly!

nick said

at 5:03 pm on May 18, 2009

I have pretty much all the parts , I am in the process of knocking together some spindles at the moment, I am hoping to have a completed drawbot (of magnificent size:-) before saturday. which can then be torn down and reassembled and replicated / hacked on the day.. it would be interesting to add either a camera and / or memory card storage with menu system to the project to avoid reprogramming every time we change the image.

nick said

at 5:05 pm on May 18, 2009

and to mr peters , I have some spare atmega 128 if that's your flavour

nick said

at 5:12 pm on May 18, 2009

sorry I mean 168

Nick Peters said

at 6:01 pm on May 18, 2009

It's a 328 chip that was in it but I think they're interchangable, no? It might be a good opportunity to at least see if it would fix it to get a new chip - thanks :)

Adam Ray said

at 6:33 pm on May 18, 2009

Nick - I have a spare Arduino so no worries. In terms of parts I dont have any for this project. However, pay day is on Thursday so will hopefully get most parts from Fanell or Maplin. I'm quite sure we could achive this in one day.

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