The Robot Builder's R-duino
June 25, 2011
June 24th, 2011.
I've been asked if I can make a board similar with the Robot Builder's Shield that also has the microcontroller on board and is compatible with regular Arduino shields. Not an easy task to do if I want to keep it with through hole components, but it's a challenge.
So I have designed a first prototype of the Robot Builder's Arduino R-duino. Features:
- same size as a regular Arduino board, with 3 mounting holes
- 6 servo connectors (power from battery, digital pins 8-13),
- 6 sensor connectors (regulated 5V, all analog pins),
- a SN754410 H-bridge (1 amp per motor, digital pins 4-7, uses Timer0 for PWM),
- screw connectors for motors
- pins 2 and 3 (external interrupts) available for encoders,
- a FTDI connector (to program the board using a USB-serial cable),
- a ISP connector (to program the board using a hardware prorgammer),
- polarized Molex connector for the battery (4.5-12V, no more than 6V if you use servos),
- reset button,
- pin D13 LED,
- power LED,
- power switch,
- 1A LDO voltage regulator,
- all Arduino female pins are doubled with male pins, arranged to allow easy prototyping shields,
- filtering caps near the sensor and servo 3 pin connectors.
J1 is to select power to the servos. J2 and J3 allow motor control mode, either 2 pin (Enable High, one Dir for PWM and the other for direction) or 3 pin mode (PWM on Enable, 2 direction pins). In 3 pin mode, 2 I/O pins allocated for servos are routed to the motors, so you end up with 4 servo connectors available. The LED on D13 has no selecting jumper, so it will flicker when a servo is connected to the same pin.
One more thing, the board does not have a 3.3V regulator, so even though the 3.3V pins are in place, they are not connected to anything and do not provide power for other shields. I don't think I can cram in a TO92 regulator in there...
Here is a picture, the blue is the bottom, GND plane, the red is the top, 5V plane. Round pins are male, oval pins are female.
If you click on the pictures will bring a (latest edited) higher resolution version.
Let me know what you think!
September 13th, 2011:
I was told that the Arduino name is trademarked and can't be used on a product without approval and pay a license fee. So, I have re-named the board the Robot Builder's R-duino and I will order new boards with the new name, take new pictures and change the docs. Until it is all done, I can't sell any kits. Apologies to the Arduino team and thanks for understanding.
June 27th, 2011:
Updated the pictures after changing the 1A LDO regulator with the 3A LDO regulator. This is the final change before ordering the boards.
July 26th, 2011:
I got the boards from SeeedStudio in the mail today. They are a bit thinner than the boards from PCBcart and have white silk screen. Other than that, I think they look great. Here they are:
I got 12 boards and half of them were e-tested. From the ones that were not tested, I soldered all the parts so you can see how it looks like:
To test out the board, I have mounted it on my LMR Start Here Robot:
The only shield I have is a Color LCD Shield V2.0 from nuelectronics.com. I plugged it on the board to see if it fits and if the sensors and servos connectors can be accessible. The servo connectors are a bit tight to plug and half of the sensor connectors are covered by the shield. That may not matter much, as the shield uses pins D8, D9, D10, D11, D13 and A0, so only the pin D12 is available for servo use, but I can do a IR sensor sweep and print it on the LCD. The motor pins are unaffected by this shield.
I haven't programmed the board yet, that will be done tomorrow with some tests to see if all works properly.
Update Aug. 7th, 2011:
It seems that somehow I messed up with the SparkFun's FTDI connector and not swapped the Rx and Tx pins. For the first batch of 10 boards, the customers will receive a free adapter that swaps the pins. Then you can program the board and everything works fine.
Video of it in action comming soon.
Oh, the Robot Builder's R-duino kit is in the store!