Search found 60 matches

by DrRob
Sun Oct 14, 2012 8:43 am
Forum: Electronics
Topic: Cheap way to connect ShapeOko by wi-fi?
Replies: 1
Views: 840

Cheap way to connect ShapeOko by wi-fi?

http://electricimp.com/ It's a cheap (£19.50 in the UK http://www.coolcomponents.co.uk/catalog/electric-p-1048.html ) wi-fi enabled microcontroller in an SD-card form-factor with a cloud-based development environment. Wi-fi settings are configured by using a smartphone app that passes messages to th...
by DrRob
Tue Oct 02, 2012 12:16 pm
Forum: PCB Fabrication
Topic: Anybody actually milling pcbs with shapeoko?
Replies: 13
Views: 4759

Re: Anybody actually milling pcbs with shapeoko?

Do you think it might work to put a rotation sensor on the cutting tool, and detect the very slight loss of rotational speed when the bit bites into the copper? Edit: that won't help keep an accurate level while cutting across the board though. You'd have to keep raising a re-lowering the tool to re...
by DrRob
Fri Aug 03, 2012 12:04 pm
Forum: Electronics
Topic: Setting current limit on A4988 drivers
Replies: 5
Views: 6116

Re: Setting current limit on A4988 drivers

edwardrford wrote:Hi @DrRob! I thought you had disappeared. It's nice to hear from you again.
I'm still here, but there simply aren't enough hours in the day to fit everything in.

:-(
by DrRob
Thu Aug 02, 2012 11:44 am
Forum: Electronics
Topic: Setting current limit on A4988 drivers
Replies: 5
Views: 6116

Re: Setting current limit on A4988 drivers

Copying an answer from the old Google-groups ShapeOko forum: On 12 March 2012 20:50, Rob Noble wrote: Hi, I emailed Pololu to ask whether the current adjustment should be made with motor power on or off, and motors attached or not, and here is the reply: On 12 March 2012 20:43, Clint Barnes <clint@p...
by DrRob
Fri Jul 06, 2012 8:47 pm
Forum: GRBL
Topic: GRBL commands
Replies: 5
Views: 2334

Re: GRBL commands

Tom Smith wrote:If you happen to abort a run that is in Inches, but you are used to using millimeters, send a G21 before manually entering a coordinate like z20, or you might launch your entire Z axis as I did tonight!
Oh, I've been there, and have the holes to prove it.

:shock:
by DrRob
Tue Jul 03, 2012 12:12 pm
Forum: Design Ideas
Topic: Belt anchor with adjustable tension
Replies: 3
Views: 3540

Re: Belt anchor with adjustable tension

That looks good. You might want to loop the belt over onto itself, teeth to teeth, to create a flatter surface to clamp down onto.

If you haven't seen it already, there are some other belt anchor upgrade suggestions on the wiki: http://www.shapeoko.com/wiki/index.php/Belt_Anchors

Rob.
by DrRob
Sat Jun 30, 2012 1:33 pm
Forum: Electronics
Topic: Electronics desicions, in the UK
Replies: 14
Views: 4074

Re: Electronics desicions, in the UK

I don't know what it's like in other countries, but it isn't very consistent in the UK. I got over charged for import tax on the stepper motors. But I didn't get any taxes or import duty or customs clearance charges for the ShapeOko kit itself. The box just turned up and that was that! I was charge...
by DrRob
Wed Jun 27, 2012 11:21 am
Forum: Electronics
Topic: Correct specs for steppers?
Replies: 3
Views: 810

Re: Correct specs for steppers?

aldenhart wrote:Perhaps Dr. Rob could do a calculator sheet to sort this out.
http://www.cleavebooks.co.uk/scol/cctorq.htm

:-)
by DrRob
Wed Jun 27, 2012 11:07 am
Forum: Discussion
Topic: ShapeOko racing league
Replies: 37
Views: 10370

Re: ShapeOko racing league

All this "my one's faster than yours" is very childish

and I can't wait to join in. :-)

If we add a small circle in the corner at the start of the g-code, and repeat it again in the exact same place at the end, can we use that to tell if steps have been missed?

Rob.
by DrRob
Tue Jun 26, 2012 8:12 am
Forum: Electronics
Topic: Steppers moving erratically
Replies: 15
Views: 3010

Re: Steppers moving erratically

I did NOT adjust the pot when I was testing as I'm using totally the wrong voltage. IIRC, the pot takes a fraction of a reference voltage to compare with the voltage across a current-sense resistance, and because the reference voltage is fixed it means you can set the pot with a 12v motor supply an...