Step 6: Putting it all together


- Two laser head slider mechanism with stepper motors (preferably matching), scavenged from old CD drives. Cost: a few bucks a piece.
- One InkShield kit, with ink cartridge and cartridge holder. Cost: $57
- Optional: additional HP C6602 inkjet cartridges. Cost: as low at $17
- Arduino Uno. Cost: $30
- Two SN754410NE H-Bridge motor drivers. Cost: $5
- Arduino prototyping shield and/or tiny breadboard. Cost: $4-21
- Wires, machine screws, standoffs, enclosure. Cost: Free to $$$, depending on how fancy you want to be.

Total cost for our version: about $150, shipping/handling for parts included. The pictures above show two different versions we made. The second one has a nice acrylic top plate, and a lot more space to put things in between.

The bottom CD drive mechanism moves the blue plate holding whatever you're printing on (such as an agarose plate). The top CD drive mechanism is set at a 90 degree angle compared to the bottom one, and moves the inkjet print head. We used Shapelock and some screws to attach the bottom platform to the laser head, and to attach the inkjet cartridge holder to the top laser head. The electronics consist of an Arduino Uno at the bottom, then the white InkShield (connected to the inkjet cartridge holder with a nice white ribbon cable), and then a protoshield with the stepper drivers on top.

The gridded paper strips on the bottom and top platforms allow us to track the position of the X and Y stages. Total print area is about 1.5 inch in both directions, with a resolution of 150 micron per step. Note that the resolution of the stepper motors is similar to the resolution of the print head: 96 dpi is a 265 micron pitch, but the dots printed by the print head are clearly separated - more like 150-200 micron.