Let's Make Robots!

The Robot Builder's R-duino

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!


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Where is the store? What is the cost? Will more be made available after the initial run?

The store is: robotxdesigns.ca. I will add this as a product as soon as I will have the docs done. You can pre-order by sending me a PM with your Paypal address. The cost is $30 for a kit, plus shipping ($2 for Canada, $4 for USA, $5 for all other countries). I have all the parts in stock. After this initial run, I will order 50 boards from PCBcart that will have minor corrections/improvements. Unfortunatelly, I am still waiting for the USB-serial cables, because I got similar ones that were crap (no chip inside).

What are those big blue connectors for and where do the motors go? I can see the servo and sensor pins but i didn't see anything marked motor... a little help plz...

Blue, those are the motor screw connectors! One is marked M1 and the other is marked M2 on the silk screen, a bit hard to see in this photo. Easier to see if you look at the PCB design picture.

And the kits are in the store!

My son and I are assembling the board, which is taking a while, because I'm letting him do the soldering. We'll get there eventually.

In the meantime, I've been trying to think how to best take advantage of the capabilities of your newest board. Since the R-Duino will work with Arduino compatible shields, I've been thinking about what shield would nicely complement it.

I'm thinking about adding a NKC Electronics motor driver shield or something similar. This board uses the same motor driver, but with digital pins 9 and 12 for one motor and 10 and 13 for the other. Since the R-Duino uses pins 4-7 for its onboard motor driver, this should give me a 4WD capable robot.

Could be cool.

Hehe, nice! If you do use that shield, you should note that it uses Timer1 pins for PWM so you will not be able to use the Servo library at the same time. Perhaps the SoftwareServo library could work.


They are here! The new boards are here, I just got them from the post office. I'll be taking pictures of assembly and update the guide then they are going to be in the store!


Yeah, they are here, just in time for Christmas shopping. 

Read more here: http://seriousrobotics.wordpress.com/2011/12/12/the-robot-builders-r-duino-v2/

and here: http://letsmakerobots.com/node/30251?s=l