Sci Fi Your Pi: PiDesk - Project Update #17

9 Aug 2015

Previous posts for this project:

Project Update

Project Update

It's been a busy week for me, not so much for the desk though. First, I went on holiday with my wife and kids to the belgian coast for the week, and I closed the weekend by introducing a visitor from New Zealand to belgian beers and strolling through Brussels together with another belgian member. First one to guess both members gets 10 points. (No real points, no prize can be claimed!)

Anyway, back on topic ... there have been little bits of progress on the desk. Let's go over them ...

Touch controls

The conductive pads and tracks have been laid out on the desk. All that is left to do is to hook them up to the prototyping board I made last time and hope they work as expected!

I started off by laying out the copper tracks and then drew the shapes of the contact pads using a drinking glass and a marker. Afterwards, I carefully painted the pads using conductive paint.

Power distribution

To simplify things, I'd like to power the entire setup from a single power supply. The two voltages required are 5V (Pi, LED strip) and 12V (Stepper motors, laptop screen), so I plan to use a single 12V power supply and have a converter to step it down to 5V for the components that require it. This also means that different splitters are required to ensure every device gets powered.

Motors and endstops

I've mounted the motors at the bottom of the frame using some MakerBeam pieces I had around. With my printer still giving me headaches, I ended up taking a piece of wood, drilling holes for the threaded rods to fit through and make a larger hole on the bottom side holding the two captive nuts. First tests indicate the stepper motors have no trouble handling the weight and can lift the screen assembly as expected. I'll try to get a video out for this in the coming days.

The endstops have been installed on the side of the frame, the first one triggering when the screen is lowered flush with the desk, the other one when it's been raised enough. You can see both switches on the picture in the next paragraph.

Cable management

Another thing I managed to do, is some basic cable management, ensuring the wires of the motors and endstops are tucked away neatly. I used a plastic cable guide for that, which I attached on the side of the screen's frame.

Python

Finally, I started merging the different bits of code I created over the course of the challenge, combining all the different features like sound effects, neopixel control, capacitive touch, etc ... I haven't been able to test it yet, that's planned for next week. If everything ends up working as expected, I can start finalising the build and get testing and tweaking. I'm not using a particular IDE for this, as I've found the Sublime text editor to do the necessary syntax highlighting and completion.