Laser Scanner Part 2: (Perimeter Mode)

   Similar to the input devices assignment, I decided to try to visualize the scanner mechanism I cobbled together.    The architecture is as follows:

block diagram
And here is a picture of the actual device:

Most of the components are were picked up here and there surplus.   The laser range finder was designed for checking products on assembly lines (for example, measuring the height of a glass jar lid to see if it is screwed on all of the way.)   The data-sheet describes measuring how many sheets of paper are in a stack, so it may be pretty accurate.   The output is an analog 4-20ma current loop.  

This week's progress...

All of the above is interfaced to a tiny45 (new board designed and etched.   See hotplate solder below) which appears to a laptop as a custom USB HID device.   The microcontroller takes commands, steps the motor, and reads the sensor -- sending the results back to the laptop.

I played around more with the HID drivers... more specifically, the software I wrote/modified last time was C based.   This week I spent a block of time getting the HID device readable under Python.    I also tried to improve the motor control on the microcontroller side.

I also added some code to try to massage the data and plot the output using pylab.


And here is what it thought it saw scanning a box:
And here is a toy, and what it saw:

Additional Notes:

hotplate solder