Building a label printer using Python, Arduino, duct tape and paperclips. And: ● Hot glue ● Cable ties ● A washing peg ● A ruler ● A hobby servo ● Skateboard bearings ● Polymorph (the plastic, not the company) ● Sandpaper ● A pencil ● A Coke can ● A series of tubes ● Plus various cannibalised bits from my garage 

Hackathon ● Half a weekend ● Build something useful ● Or not ● One step at a time ● TLAR design methodology I had an idea…. 

The physical build Masking tape roll on a threaded rod, turning slowly. One rotation moves it 1mm sideways (spiral). Detect a starting point (Coke can, paperclips). Raise/lower a pen to create pixels. 

Software Laptop running a Python script: ● Convert text to image ● Convert image to list of lists of colour values ● Send timed up/down commands to Arduino Arduino is just a dumb controller: ● Drive the motor ● Send a start position trigger to the laptop ● Receive up/down and move the pen 

Python: Getting the image 

Python: Control 

Results: ● 11 hours zero to Hello World ● 48 lines of Python code ● 68 lines of Arduino code ● 0 test coverage ● 40 labels printed to date ● 8 minutes per label ● 1 lightning talk Definitely worth it, would do again. 

http:/ /johan.beyers.co.za Talk to me about: ● Python ● Takealot (We’re hiring!) ● Maker evenings (on hold) Or some other projects: ● 3D printer ● Dog speedometer ● Simple drawing machine ● Perpetual Pendulum Wave ● Electric bicycle 

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