There are also four red LEDs (PWMA, DIRA, PWMB, DIRB) that are wired
to the control lines directly, showing what your code is doing and also if the
pins are configured correctly.
The control signals are connected to LEDs on this revision so you can see
what your program is doing! In this photo, DIRA is illuminated (meaning the
direction is reversed), and PWMA is half-illuminated, indicating that the
signal is being pulse width modulated.
When the DIR LED of a side is illuminated, the driver will allow current from
pin 2 to 1, and the blue LED will be lit. Alternately, the yellow LEDs will be
lit. With a motor connected, the inductive effects can cause the opposite
drive LED to illuminate slightly; this is OK. The
blue and yellow
LEDs are
there to help show what the actual outputs of the driver are doing. Use the
red
LEDs to debug your code.
LEDs in operation
Supply Voltage
The Ardumoto Shield should be powered through one of two power supply
inputs. Pick
one or the other
:
1. The
barrel jack
input on the Arduino.
2. The
V input
on the shield
If you don’t want to use the Arduino’s barrel jack input, you can use the
V
input on the shield
instead. This voltage input will supply
both the shield
and the Arduino
. Like the motor outputs, this connection is broken out to
both a 3.5mm screw terminal and a 0.1"-pitch header.
Do not supply power to
both
the Arduino barrel jack input and V on the
shield! Doing this will cause current to flow from one power supply to the
other if the voltages are not identical.
Spec'ing a Power Supply
Because V powers both your Arduino and your motors, you need to take
extra care in deciding what you’ll use to power your Arduino/Ardumoto
combo. Not only does V have to fall within the acceptable range of your
Arduino (usually 6–15V), but it also has to meet the specifications of your
motor.
IN
IN
IN
IN
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