Mini Prop Undershield (and Arduino Too!)
By Chris the Carpenter
November 13, 2011
November 13, 2011
I have been a bit addicted to this little mini Propeller board (M44D40+) designed by Andy Lindsay. It is an awesome little board, with a DIP-40 footprint and pinout but contains a SMD Prop, crystal, EEPROM and other assorted doo-dads to make it go. A standard 4-pin sync connection sticks out one end. The forum post about this board is here.
This board was just begging to be used on some kinda tiny little robot but of course, needed a motor driver, some ADC's and an easier way of plugging everything in. I designed what I call an "Undershield" which it turns out, works just as well either on top of, or under the mini prop board. It is just slightly wider than a DIP-40 chip and a bit longer as well ( .985" x 2.488") but still contains:
- 5v Regulator
- 3.3v Regulator
- Motor Driver
- MCP3202 ADC Chip
As well as connections for:
- Power in for data (to regulators)
- Power in for motors
- Motor A/B out
- 2 ADC channels (with 3-pin connector (3.3v))
- 2 Servo connections (with 3-pin connector, 4.7k resistor on signal wire (5v))
- 1 Sonar connection (with 3-pin connector, 10k resistor on signal wire (5v))
What you see here is just a prototype. I am working on if and how I can produce this guy. The SMD work was all done by hand and thus, won't fly in terms of producing a lot of these guys. On the other hand, this could be a great opportunity to start learning about stencils and reflowing. I love learning new stuff! I am also working on the possibility of carrying the M44D40+ Mini Prop board as well and thus, being able to sell the pair as a set. Please let me know if you would be interested in any of this. --I will put you "on the list" for the first batch. firstname.lastname@example.org
Oh! I should mention that I think this guy has been dubbed "PPPB" by Mr. Gareth from the Land of Swiss Cows... (Purple Priceless Propeller Board) and I may have to stick with that name. :)
Just about everything you would need for a little robot.
Well, the inspiration continued... I liked the looks, functionality and size of the Prop so much that I had to do the same with an Arduino. Not but just yesterday, I sent off the Gerber files to get the first batch of Arduino undershield PCBs made. They are very similar to the Propeller board above, with connections for all the things you may find on a small robot. ADC's, motordriver (L293D), servo and Ping connections --everything you need. I designed this guy to work with the Arduino Nano so one will also have a USB connection on-board as well. All nice and tidy in just over 1"x2".
Like I said above, the boards for the Arduino version just went out so we are looking at around 4 weeks to get these guys "on the shelves". The first batch is pretty small (only 10 boards) so if you would like to be put "on the list" for one of these, please email. email@example.com