Review
raspberrypi.org/magpi The Official Raspberry Pi Projects Book 189
TINY 4WD ROBOT KIT
Last word
A great little robot kit which could do with some
better build instructions. Once it’s built, however,
you have a lot of options and plenty of ways to
make it your own.magpi.cc/Tiny4WD
£55 / $60
solder a 40-pin and a 20-pin
header to the Explorer pHAT
supplied with the kit, as well as
soldering a GPIO header to the Pi
Zero. The rest of the setup is easy:
install the software on the Pi Zero
(running Raspbian) and you’re
ready to play!
Flexible control
From here you can use the test
scripts to control the robot
using a USB controller, or start
making it more autonomous. The
Pimoroni library for the Explorer
pHAT is easy to understand –
so, with the docs open and the
examples to hand, you can easily
start creating your own programs.
Each side of the Tiny 4WD is
powered by one of the motor
outputs on the pHAT. This
means that, for example, both
left wheels will always run at
the same speed and direction as
each other. This makes it easy to
turn on the spot, and gives it full
power when it’s moving forwards
and backwards.
The Tiny 4WD is easy to
customise. There are extra inputs
and outputs on the board, so
you can start adding additional
sensors. There’s a camera mount
that could be used to attach an
ultrasonic sensor, or a Raspberry Pi
Camera Module – like the robots in
the Formula Pi racing series.
Power choices
Choosing a power supply can be
tricky. The idea is to house your
power source between the layers
of the chassis. However, the
narrow gap, partly blocked by the
wires to the motors, limits the
size of any power supply. You’ll
also need to think about power
capacity – the motors will be
powered from the Pi’s GPIO pins,
so your Pi will need more power
than you might expect.
Thumbs up
We do like this robot overall. The
build quality is great, with a sturdy
chassis made from thick acrylic,
decent micro motors supplied with
the kit, and the inclusion of a great
motor controller in the Explorer
pHAT. The soldering requirements
make it unsuitable for an absolute
beginner, but it’d be great as a step
up for novices. It could even be
used as a base by more advanced
robotics users, as you can easily
swap out the HAT and use a bigger
Pi to add more functionality.At the time of writing, supplies
are limited for this kit, but more
units are being made all the time.
If you want one, you may just
have to be patient. We think it’s
worth the wait, though.