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

RoboBrrd Building Video 1

There was a lot of footage taken during the build of the latest RoboBrrd. Here is the first of these videos, there’s going to be a little over 10 in total!


Watch on YouTube

Hope you enjoy the video, the series of videos will be a great companion to the Instructable. More of the documentation will be arriving online as we sort through it! :)

I started learning Eagle last week, it was quick to jump in and get started learning. There’s also lots of cool parts libraries out there with Arduinos or other various components that you would need.

Here’s me learning Eagle:

Screen Shot 2011-11-22 at 11.52.07 PM

Here’s where the circuit is at right now. Have to add in the headers and such, and place it on the proto-screw shield!

Screen Shot 2011-11-27 at 11.37.42 PM

More later!

7 CommentsLeave a Comment


  • Britt

    3 years ago

    Um… why the *adjustable* regulator? Why not a fixed one like a 7805? You can eliminate two diodes, a resistor, and a trimpot that way…

  • Erin, the RobotGrrl

    3 years ago

    The 7805 is limited to only 5V. Sometimes with all of the servos you will need a little bit more than 5V to account for the voltage drop. When adjusting the trimpot, I usually have the servos moving around so that I can set the voltage properly.

    Thanks for the question Britt, this will be included in the documentation!

  • Britt

    3 years ago

    If you are getting substantial voltage droop, then something is wrong: either your wires/PCB traces are too small, your voltage regulator can’t handle the current, or your primary power supply can’t handle the current. Properly set up, a 7805 should keep 5 volts on the rail all the way up to 1.5 amps.

    Also, those servos aren’t that sensitive to rail voltage… they often operate in RC applications with really marginal wiring and power supplies.

  • Erin, the RobotGrrl

    3 years ago

    You know, I looked into this more… so much so that I spent 8 hours debating/learning more about it from a lot of friends.

    The Vout from the LM317 is 5.1V. 0.1V is not substantial for this case. The range of the voltage for the servos is from 3-6V. 5V is the common voltage used for servos, that doesn’t mean that they can’t be over or under 5V.

    LM317 is fine for this application. We may look in to the 7805 going forward if it is less expensive, of course. :)

    “But what about the voltage spikes!”
    This is a good question. From what I have observed, this does not have a noticeable effect on RB’s servos.

  • Frank Buss

    3 years ago

    Your Eagle PCB layout looks… interesting :-)

    For the voltage regulator I would suggest to use a second regulator for the Arduino part, maybe something like this, if 250 mA is sufficient:

    http://search.digikey.com/us/en/products/MCP1700T-5002E%2FTT/MCP1700T5002ETTCT-ND/652682

    Then you can regulate the LM317 all from 3V to 6V for the motors and if the motor stucks and draws high current, or there are other problems, the Arduino won’t reset (LM317 limits the current, but the voltage will drop) and you could even detect the problem (maybe measuring the current with an AD input of the Arduino and a 0.1 ohm measure resistor) and stop the motor.

  • Erin, the RobotGrrl

    3 years ago

    Interesting! I’ll look into this more ;) Thanks for the ideas!

  • Lauretta Koester

    3 years ago

    Everything posted was actually very reasonable. However, consider this, what if you were to create a killer headline? I ain’t saying your content isn’t good., however what if you added something that makes people want more? I mean RobotGrrl.com » Blog Archive » RoboBrrd Building Video 1 is a little plain. You ought to peek at Yahoo’s home page and watch how they create news titles to grab people to open the links. You might add a related video or a picture or two to get readers excited about what you’ve written. Just my opinion, it could bring your posts a little bit more interesting.

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