Little Box of Geek Project - Part 1

You will need:

• A Raspberry Pi, power supply and peripherals (including up to date image on SD card)
• A thermal printer, a 7.5v/2a power supply, and roll of paper
• A cardboard box
• A button
• Cables
• Breadboard
• A resistor
• A solder-less DC connector
• A small crosshead screwdriver
• A cable striper
• Scissors
• A pen
• Some help from an adult for the fiddly bits.

Prepare the thermal printer by connecting the cables. First plug in the data cables (green, yellow and black) to the printer. Next connect the power cable (red, black).

Cut off the end of the power connector and replace it with the solder less dc connector so that it can be plugged into a dc power supply (must be between 5 and 9v, 2a). Make sure that the red wire is put into the positive (+) and the black wire into the negative (-). Screw in tightly.

Test that the printer works with your power supply by plugging it in. If the green light flashes and when you press the paper feed button, the paper comes out, the printer is ready to be plugged into the Raspberry Pi GPIO pins.

Using male to female jumper cables attach the RX of the printer (yellow) to pin 8 and the ground of the printer (black) to pin 6 on the Pi. GPIO layout Note: Make sure you read this first :)

Connect your pi to a keyboard, mouse, monitor etc. You should have already setup your raspberry pi, if you have not done this yet check out GGD episode 5.

We need to first setup the Raspberry Pi serial port and change some settings.
Install the required files by typing the following into a terminal window.

sudo apt-get install python-serial
sudo apt-get install python-imaging-tk

Next give the serial port permission to dialout using:

sudo usermod -a -G dialout pi

We also need to edit this file:

sudo nano /boot/cmdline.txt

By deleting:

dwc_otg.lpm_enable=0 console=ttyAMA0,115200 kgdboc=ttyAMA0,115200 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 rootwait

and replacing it with:

dwc_otg.lpm_enable=0 console=tty1 root=/dev/mmcblk0p2 rootfstype=ext4 rootwait

Finally remove the last line of /etc/inittab and restart your raspberry pi using:

sudo shutdown -r now

(With thanks to natemcbean.com tutorial)



Next we need to download the python files needed to print from github. First you will need to install git-core onto your pi using:

sudo apt-get install git-core

create a directory on your pi to download your files from git hub to using:

cd~/git

to download the printer repository use:

git clone git://github.com/luopio/py-thermal-printer.git

Finally we need to edit the following file:

sudo nano printer.py 

To add this line at the top:

#!/usr/bin/env python 

and to check that it is pointing to the correct port:

/dev/ttyAMA0

Run Printer.py and a test page should print.

What are you waiting for? Hot foot it to Part 2 for more fun!