SBC Candidate: Pololu Zumo Shield

[JayBeavers]

The Pololu Zumo SBC

This is my current favorite SBC for simple robotics. It's what was the basis for my Sumo NodeBot at RobotsConf 2014. It doesn't run Node onboard, but I remote controlled it from Node on my MacBook.

The Zumo board assumes you're mounting an Arduino UNO for it. It contains "what the Arduino doesn't already have" and it omits the MCU and power regulators that the UNO provides. The functionality of the board is:

• Dual brushed motor controllers for the Pololu Micro Metal Gearbox motors
• Buzzer
• 9 axis IMU
• 7.5v Boost Regulator
• Support for an additional reflectance sensor array for line following

Not bad for a $25 PCB, eh?

Lucene University used this chassis and made their own PCB with an onboard ARM Core.

If I could redesign

If I were able to redesign to this board, I would:

• Add an onboard ARM Cortex with BLE (e.g. Nordic nRF51) with a decent antenna
• Add onboard power regulators for +3.3v and +5v (as needed by the board)
• Add a plug for the motors rather than soldering into the board (like the Lucene board above)
• Add a plug for the batteries rather than soldering into the board
• Add builtin support for the Pololu Magnetic Encoders on the board so we get a closed loop drive train
• Add a more standard polarized connector for recharging the 4x AA batteries (e.g. a 2.1 mm barrel connector?)

With this in place, we could continue to use the Zumo chassis or design a new base chassis for different drive trains or larger chassis.

In a perfect world

To make this even more useful, I would stretch it to:

• Support brushless motors. RC planes and quadcopters have really pushed the brushless motor industry forward. Check out Hobby King for a dizzy array of choices.
• Support higher current motors, e.g. 10-25 amps / channel so it can control larger chassis (e.g. monster truck)
• Support a selection of motors and encoders from small (sumobot sized) to medium (monster truck sized) so you don't need to swap boards between designs.
• Support the option of 4x AA Rechargable or LiPoly/LiFe. Support a smart charger for all battery chemistries
• Add an onboard 'power meter' -- could be as simple as an RGB pixel that turns on when you press a pushbutton that changes color and intensity based on battery charge
• Add an onboard 'low power' warning -- needed for LiPoly batteries because draining them too low destroys them

[JayBeavers]

FYI, I've ordered an nRF51-DK which is a reference board by Nordic Semi that has an Arduino form-factor. Want to see whether this board will properly mate with the Zumo board, if so will get a mostly functional (would not support magnetic encoders) prototype of the concept.