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Charlie Peppler

Charlie Peppler

Question #1:  Where to start?

Well, if we're going to get something to move, we might as well start at the bottom of the "stack".  Given that FRC uses all DC motors (steppers and servos are for more precise motion control), we should start there as well. 

Since we are working with the RasPI, motors need to be smaller.  12VDC motors (without proper power protection) would fry the Pi. 

Fortunately, I happened to have an old Lego Mindstorm set I bought my kids when they were little (all the way back to the RSX...).  I found two Lego motors that should do well.

Of course the RasPi has lots of low power I/O capability (Digital Inputs/Outputs, UART, SPI, I2C, PWM), but not enough to drive multiple motors.  So, we're going to need a motor controller board.  We want something small that works well with the RasPi, but enough to drive motors at between roughly 3-6 VDC.  I chose this one from Adafruit

While I was at it, I ordered another Pi (I wanted to dedicate one to the robot and I'm using my first one).  I also ordered some standoffs (to keep the RasPi and the MotorHAT separate but well supported), a power supply and an SD card for the RasPi.  Between these new pieces and the left over parts I should have enough hardware to get started.


Just a note about power supplies...I'm going to start with all the pieces on a prototyping board, connected with two separate plug in power supplies, one for the RasPi, and one for the motors.  We need to keep in mind that eventually we need to be mobile. 

For the RasPi, I plan on using one of those tube like rechargable batteries that generates 5V (used frequenlty for cell phones), and a separate battery pack for the motors.  Probably a holder for 4 AA batteries.  That should give 6V for the motors, and separate 5V for the Pi.

OK, so parts on order, some parts on hand, time to think about software and how we're going to drive this thing around....






My name is Charlie Peppler.  I have always had a passion for using computers to move things and make things.  I've spent most of my career in connecting computers, devices, databases, and of course people.  More on my background and why I started doing this later, but the first question is:  What the heck is a "Mentor on a Mission"?

 I volunteered as a mentor for First Robotics Competition (Team 5459 - Ipswich MA).  I enjoyed the experience, but after the dust settled on build season, I realized that there is a big gap between students who might be interested, and the technical skills necessary to be fully involved as a functioning team member during the intense 6 week build season.

I enjoy connecting hardware and software to do interesting things and wanted to learn more about FRC and building robots (along with students) during the off season.  I started thinking about what would be necessary to create a minimal working testbed in my home to work with and learn all the various components.  
I quickly realized it was cost prohibitive to recreate the Kit of Parts (RoboRio, Power Distribution Panel, Player station, motors etc.) used in real competition.  I didn't want to spend the money, and for more kids to get kids "hands on", there is a real need for a cheaper "on ramp" platform to work on basic skills (mechanical, electrical, software), that would prepare for having fun, and being productive and successful through the build season leading to FRC competition.  
Turning around in my office chair, I looked at my trusty Raspberry Pi.  I bought it over a year ago, connected it to my home network, and ever since have been experimenting with various software projects, connecting hardware and open source software.  I've wired up an RFID board to the Raspi, written a driver based on libnfc and connected it to MQTT (future blog post?), hooked up LEDs and switches, and driven them with a variety of programming languages (C, Node-Red, Javascript, Java, Python, MySQL).  This thing is extremely capable, has lots of available development tools and open source repos, it's expensive, and has proliferated widely.  Some advanced FRC teams are already using the Pi3 as a vision co-processor.  
My mission became clear.  I wanted to recreate a stripped down version of the FRC competition environment (player station, robot comms, robot software, mechanical and electrical) that would allow me and students to learn, work and play in that gap between Lego Mindstorm and full blown FRC an affordable price!  

If we could get that all running, there's plenty of headroom to learn more.  Thus ...Mentor on a Mission.

PS, I'm recruiting presently recruiting like minded mentors to help make this platform a reality.  If you're interested contact me.







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