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The GrassShark is a small, robust, four-wheel drive buggy that can be used to transport a camera into remote, narrow, locations.

This post will link to the parts needed to put together the basic robot, with suggestions for some more advanced adaptions. Note: most of these links will be to UK based companies because those are the companies we used.

The Basics
  • All Metal Chassis 4WD Robot Kit (ATV) – we used Rapid electronics, but the same chassis is available in a few places
  • Raspberry Pi Zero (with case) – The Pi Zero is small and fits perfectly on to the robot chassis – try to get the Pimoroni case as well as this, and the small nylon bolts that come with it, make mounting the Pi to the chassis a lot easier.
  • 640 board – The 640 board can drive up to 6 DC motors, which is more than enough for our needs here – it can also control 2 servos in case we want to add a gripper, obstruction detector or pan and tilt camera mount later. I’d recommend picking the stacking female header and either the right angle motor connections or the screw terminals.
Communication options

We can use a variety of methods to control the robot – I’ve added three below, in order of range of the controller. We tend to use an RC style controller as it gives you most flexibility and longest range.

  • PS3 style controller and dongle (short range) – a basic game controller ( and dongle ) that you’ll find with most game consoles.
  • Wifi Dongle (medium range) – WiFi control via a browser or phone can give a longer range – you may want to consider adding wifi as well if you are using an RC controller as we can stream video from the robot in some cases.
  • RC transmitter and receiver (longest range) – The longest range, but also more costly. We find RC is a lot more reliable than any other method, and the 640 board has a connection for a CPPM compatible receiver to be connected directly to it.
Camera(s)

The first camera below, the Pi Zero camera, may be the only one you’ll need and can be used to stream content back to your computer. But sometimes you want higher resolution footage as well. We’ve mounted both a Go Pro camera and a 360 degree camera to our GrassShark for better quality footage.

  • Raspberry Pi Zero camera – be sure to get the Pi Zero replacement cable as well as you’ll need this to attach the camera to the Pi Zero.
  • Go-Pro or similar – A Go Pro is quite expensive, but provides exceptional quality footage, other HD sports cameras are available so I won’t link to any here.
  • 360 degree camera – We used a Kodak SP360 4K camera on our GrassShark, primarily because it was one the few 360 degree cameras that had a waterproof case (which we needed for other robots).

Now we have the parts list, the next few posts will be putting the robot together, and then we’ll work on improvements…

 

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