Archive for June, 2014

RoboPi readDistance()

Monday, June 30th, 2014

I’ve updated the RoboPi User Manual to v0.81, to match the current API (and firmware) release levels.

Elf RoboPi + Raspberry Pi Robot @Mikronauts

This update consists of

  • documents the final version of the Spin API and Pi library readDistance()
  • provides wiring instructions for using supported ultrasonic range sensors
  • updates the tested/working status for the supported sensors

Supported sensors:

  • Parallax Ping
  • SeeedStudio SEN136B5B
  • HC-SR04

You can find the updated documentation on the RoboPi product page at

Servo Power

Saturday, June 21st, 2014

Now that HexPi has all his hair servo extensions, I’ve decided I need to make a better power distribution board for TBMST than my first effort (shown below) for the NiCd R/C battery packs.

This time, I plan to use an ATX power supply with separate power feeds for servos 1-8, 9-16 and 17 & 18 as the next experiment. It will be interesting to see if the MG-995’s behave better with more instantaneous current being available.

I also made two modified servo extension cables that allow me to replace the power from the servo connector with external power so I can use the normally Pi 5V powered servo connectors with the ATX supply.

RoboPi can already accept separate power sources for the two servo banks (P0-7 and P8-15) on the svt2 and svt3 headers.

The Better Mousetrap Servo Tester @Mikronauts

 (click on image for larger version)

I’ll be posting the results of this latest experiment as they become available!

HexPi gets shoes!

Wednesday, June 18th, 2014

I finally had time to work some more on HexPi.

I added 50cm extensions to all the servos, cleaned up the wiring, and gave HexPi three pairs of new shoes!

HexPi @Mikronauts

(click on the image for a larger photo)

For about what I just added, and the whole build log, please click on the HexPi link below:

Related Links:

Hantek 1008B Oscilloscope Review

Tuesday, June 17th, 2014

Some time ago I purchased a Hantek 1008B USB Oscilloscope specifically for high speed monitoring of up to eight analog channels. I decided to set it up to help me with HexPi and TBMST, as I’ve found my 100MHz/1Gsps scope’s two channels to be too limiting for the multi-channel tests I wanted to run.

I thought teachers, students and hobbyists might find a review useful:

At <$100 shipped, it turns out to be a bargain.

HexPi does Calisthenics!

Wednesday, June 11th, 2014

Or to put it another way – I wiggled his front two legs with “The Better Mousetrap Servo Tester”!!!

HexPi Calisthenics - RoboPi and Raspberry Pi based robot stretches his legs

(click on the photo above for larger image)

If you are interested, here is a YouTube video (HD) showing the test:

Related Links: