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“A wise robot once said to me through Serial.println- that robots teach us about ourselves.”

Stuff on the RoboBrrd Brain Board

Here is a colourful annotated picture of what will be on the RoboBrrd Brain Board! This would make a great fridge magnet or something :)

RoboBrrd Brain Board Stuff

One of the things I thought would be handy would be to have a shorting block switchey area for both the microcontroller voltage and the servo voltage. This way you can choose what power source you want to run the microcontroller off of, AND if you want the servos to run off of that same power source (from the microcontroller), or from the external regulator. Although with the redesign the servos run fine off the usb power, figured might as well add it in incase someone wants to use even more servos on RoboBrrd!

Crossing my fingers that the onboard 5V regulator won’t heat up too much. It will be interesting to test it out, especially since the copper fill below it should act as a heatsink. The reason why it is facing inwards is because if it was facing outwards, it would be next to the back face of RoboBrrd. This is commonly made out of wood, which I reckon is more flammable than the black plastic used on the headers. Plus, this is where all of the cables will be attaching in, and you wouldn’t want your finger to accidentally slip and burn on the voltage regulator.

Randomly placed picture of the board, here!

RoboBrrd Brain Board Stuff

Wondering if it will be possible to run this with just a ceramic resonator. I’m not too sure of the quality difference between a crystal and a ceramic one, especially for RoboBrrd. I will find one and desolder it to use with this testing!

There are two ways to input the voltage, the barrel jack will be great with some 5V transformers that plug into the wall. The relief holes I was inspired by the Diavolino. I think I modified the ones on here to be a few more mils smaller or closer … or something like that. These will be great with a small AA battery pack. Totally interested in seeing how long the battery life will be!

Back of the board is kind of boring, since it will be placed on RoboBrrd, I didn’t provide any useful labels. Course, thinking of it now, there should be some for the ‘useful stuff’ headers, and there should probably be some sort of pads for accessing the digital pins, not on the headers.

RoboBrrd Brain Board Stuff

It would be really cool if this board / layout could be used in other projects as well. The screw terminals are really handy. The artwork may need to change for other purposes though, haha!

In the next RoboBrrd Brain Board v2 post, will be where you can download all the filez, and the post after that will be … whenever I receive the boards in real! They are being fabbed today!

6 CommentsLeave a Comment


  • dustin1970

    2 years ago

    Looks fantastic. The Vreg shouldn’t get very hot at 12v input. Consider a via or two under it to transmit heat to the back of the board for more cooling. Consider moving the ICSP header down a few MM to keep it clear of the Atmega chip. Your current arrangement may be too tight for some programming cables. Consider adding an LED on D13 (unless I missed it). Being able to burn “blink” is a great troubleshooting step. Plus, it’s traditional. You may desire a jumper for it since some uses of pin 13 aren’t compatible with and LED.

  • Christopher Head

    2 years ago

    Heck, if you’re using 12 V in and 5 V out, consider one of these . Won’t get warm at all; it’s a switching regulator that’s a drop-in replacement for a 7805!

  • Christopher Head

    2 years ago

  • Sean Lewis

    2 years ago

    We would love to post this up as a poster. Are you thinking of making Posters of the board. We want one for our Robotics, if so.

  • Britt

    2 years ago

    Hmm… well, the biggie going from a crystal to a resonator is timing accuracy. However, the typical resonator error is within the error budget of most UART links; and most of the sensors and output devices that you will be using are either not clock sensitive (SPI or some other link that has a clock line; or analog) or has an inherent error well in excess of the resonator’s (i.e, a cheap servo).

    An ECS ZTT series resonator is specified to have a 0.3% error range… not great in comparison to a crystal, but not horrible either.

    Also, this might be of interest:
    http://pdfserv.maxim-ic.com/en/an/AN2141.pdf
    It’s an app note on UART clock errors.

  • Erin, the RobotGrrl

    2 years ago

    Dustin- Cool idea about the vias, didn’t think about that! Will do some tests and if it is too hot will try with the vias :) Hopefully the ICSP header will be able to be accessed, but will check it out and see. And yup, LED on pin 13 is there!

    Christopher- Woah! That looks like one sweet drop in replacement! I’ll check it out!

    Sean- Haha okay, I’ll create a printer friendly version that could be printed out! :)

    Britt- Interesting how much the crystal has an impact on it all. :) It will be interesting to see if the servos actually get messed up with a resonator or not!

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