The bottom side of the Ardumoto and jumpers
The A/B Isolate jumpers and the A/B inputs work together. If the ‘ISOLATE’
jumpers are all opened, and the ‘SELECT’ pins are all opened, the inputs to
the L298 are not connected to anything but the six input pins by the proto
area. They can then be used however the designer wishes in conjuction
with the proto area.
The other curious feature is the pairs of pins labeled ‘SENSE’. If you look
closely, you’ll notice each pair is shorted together, and connected to
ground. It is possible to detect current through each motor by cutting the
jumper between these pins, supplying a low-ohm resistor and measuring
the voltage across it.
Not for the faint of heart.
Possible uses:
• Current sense — break the current sense link between through-holes
and insert a 0.05 or 0.1 ohm resistor. Then, use an op-amp to amplify
the voltage across the resistor to measure current with an ADC.
• Four independent totem drive circuits using both timer one and timer
two.
• Non-coasting drive configuration.
• Bridging output (and control lines) for 4A single drive — add a
heatsink with thermal tape!
Resources
• Ardumoto Shield Schematic — A PDF of the shield’s schematic.
• Ardumoto Shield Github Repository — The design files and
examples.
• L298 Data Sheet — Everything you could ever want to know about
the L298 dual-motor driver.
• Secrets of Arduino PWM – Gives a good description of low-level
timer usage.
• Example Using TimerOne — This example included with the product
repo shows using the motor driver with the TimerOne library.
Going Further
• HUB-ee Buggy Project — Build your own buggy using an Ardumoto
shield.
• Assembly Guide for RedBot — If you’re looking for a complete,
beginner-level robotics platform, check out the RedBot Kit. It’s
Arduino-compatible, and the RedBot Mainboard has a motor driver
built into it, so you don’t even need an Ardumoto Shield.
• Getting Started with the MiniMoto — The MiniMoto is a more
advanced, digitally controlled, low-voltage DC motor driver. Great if
you need a smaller form-factor motor controller.
• How to Power a Project — Batteries? Wall warts? Solar? If you’re not
sure how to power your Ardumoto Shield project, take a trip over to
this tutorial.
Page 16 of 17
