Chatting with Sandy Noble over at the Polargraph website has been extremely helpful. 1 It looks like he’s added three changes to the Adafruit Motor Shield:
- Heatsink added23
- Breakout boards to connect the terminals to the clips for the motor leads. However, it looks like there’s a small little component of a circular purple variety also on that board.
- Extra pins for hooking up a cooling fan. Sandy says he doesn’t use them any more, but it really wouldn’t be a bad idea given that it would take hours for even a simple print.
- The photo is from Sandy Noble’s photo stream. It says All Rights Reserved and I will happily take it down if he asks and says this is not a fair use. Given that all of his stuff has been very open source, I’m guessing this was just a default setting. [↩]
- To the H-Bridges? [↩]
- Also… Where does one get a heatsink? How do you attach it? [↩]
I live near Jameco, so you’ll find 2 of these on my motor shield:
http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2077335_-1
You’re supposed to use heat sink adhesive (google it) to attach them. I believe I used super glue, though. I assume the thermal dissipation isn’t as good, but I’ve been fine (so far).
I should mention that since I’m using low voltage motors that suck up current like crazy, I also piggybacked L293Ds, so my shield has four of them (2 pairs, that is, one heat-sink per pair). “Piggybacking” is described on this page:
http://www.ladyada.net/make/mshield/use.html
Look for “ram chip heat sinks” like this (http://www.amazon.com/Xbox-Heatsinks-HANA-Southbridge-Chips/dp/B003WGLSNW) that have the sticky thermal pad attached.
@Cyrozap: Awesome! Thank you for the link!
@kongorilla: Sooo… you seriously just drop another H-bridge on top of another H-bridge and solder them together?? Could you post a picture of what yours looks like?
I’m pretty sure the “small little component of a circular purple variety” is just a jumper wire, since the screw terminals don’t have the same spacing as the header pins.
@Cameron: Ha! I think you’re right!