Slot both sides on o the grip, pushing the top into the slots like shown:

and then slotting them in so they are flat against the side:

Now slot the grip on to the servo and hold the second one loosely in place:

And finally slide the base in to place which will hold everything together and put a 10mm screw through the second grip

The put an elastic band around it as shown to keep it all tight:

The grip is now complete so we'll join the three parts we've made together

Attach the grip to the main arm as shown:

And then slot the servo horn on the base between the two sheets of perspex

and make sure the servo horn locks into place:

And then hook an elastic band over the end to hold it in place and act as a foot

Plug the base in to the arm with a 6 pin cable:

That's the physical part of the assembly done! Not too shabby!

To get the whole thing working you need to install Node.js and get the software which runs it all. Here are the steps:

1. Install Raspbian
2. Install Node.js

Run the following commands from the terminal on your Raspberry Pi

sudo apt-get remove nodered nodejs nodejs-legacy npm -y
sudo curl -sL https://deb.nodesource.com/setup_7.x | sudo bash -
sudo apt-get install -y nodejs

Then when you type "node -v" it should print out the version you installed

3. Install pigpio

wget abyz.co.uk/rpi/pigpio/pigpio.zip
unzip pigpio.zip
cd PIGPIO
make
sudo make install
cd ..

4. Install git

sudo apt-get install -y git

5. Install the Mearm program

• Clone the mearm-js repository

git clone https://github.com/mimeindustries/mearm-js

• cd into the repository

cd mearm-js

• Install libraries and run the program

npm install
sudo node server.js

The arm should spring into life and the Joysticks should control it

And here's the arm I just built working: