**About the Cricut**
Cricut cutting machines can be had for about $50 or less on Craigslist. They contain two stepper motors, a moving solenoid powered knife holder that generates 12 volts to the solenoid using PWM. They typically contain wheels that control speed, pressure, and other settings (one of them is usually an optical encoder, the others are potentiometers), a display of sorts, and a keyboard that has a ton of fairly useless buttons with green LED backlights. Additionally, an onboard USB port and the Atmel ATMega1281 chip running at 16mhz provides all the horsepower you would need. The stepper motors are controlled by eight mosfets. So in reality, you get a fairly decent XY controller board with a PWM output for solenoid or laser control for cheap! One of my future plans are to put a laser diode in place of the knife holder and see what I can do with it.
3/25/2019 - Updated the project settings and files to include contributions from Gary Stofer, for his Cricut Cake Mini machine that uses a different display and button layout, as well as GCode parser. Compiled with Atmel Studio 7, all compile errors resolved and verified it uploads to the machine and runs. Still have to perform testing because my machine is currently not responding to button or dial changes, so either the code is flawed somewhere or my machine is (which is not impossible, as I have had it opened and mistreated it with a soldering iron several times).
1/13/2019 Updated project to Atmel Studio 7
6/11/2017 Merged pull request from Gary Stofer to improve HGPL reliability
Original firmware cannot be copied from another machine (it has been locked and cannot be read from the CPU)
Original firmware cannot be restored through any PC application used for normal firmware upgrades.
This firmware has only been tested on the machine that I have. It may not work on your machine. It may cause permanent damage, and it will certainly void your warranty.
This firmware cannot read your original cartridges ever.
Cricut is a trademark of PROVO CRAFT and this firmware is not a PROVO CRAFT product. This firmware was developed completely independently, without any documentation of PROVO CRAFT products, and without any and all original firmware. If you have problems with this firmware, do not consult PROVO CRAFT.
Originally was forked from https://github.com/Arlet/Freecut
The recent updates include the option of using a Standard 4x20 LCD with a SPI interface (Cricut CAKE) or the original Oled graphics LCD that comes on the Expression machine.
If you still want to proceed:
You will need a ATMEL programmer device and an Atmel Studio 6.2 or newer installation. An ATMEL JTAG ICE MKII pod and the JTAG interface of the AVR is a good way to start. See picture and detailing connection and file Connector pinout.txt for details. you can also use an ISP programmer just to program the machine, no soldering necessary, just remove the bottom of the unit, uplug the cable from the from cartridge slot and route it out the front of the bottom of the case. Then plug this 10 pin connector into the 6 pin ISP connector, ensuring the red wire of the cable (pin 1) mates up with the pin 1 on your ISP header.
Use Inkscape to draw and send a file to the cutter. Inkscape 0.91 has an export to Plot feature (under Extensions) which sends a HPGL langauge file to the COM port where the cutter is connected to. Use 9600 baud and make sure XON/XOFF is selected for flow control. Inkscape works good on WIndows and Linux machines.