eBay has these chainable 8×8 led matrix (MAX7219) for fairly cheap.
I put together a sequence of 4, as that is all that would fit on my 3.5″ x 6″ protoboard. I connected an Extracore (mini-arduino), power regulator, thermistor and clock to make a tool to present data sent in from the USB connection. On the Linux side, I have a cron job running a php script to eat some data off a website and push it up to the board which presents the data in a loop.
After tweaking the font size, the 8×8 x 4 grids really only let me present about 6 characters and some punctuation. Enough for then. But now I want MOAR!
So, trusty OpenSCAD to the rescue!
These elements connect together and allow mounting of multiple MAX7219’s. I intend to link a set of 8 to get 12+ characters. Perhaps I’ll make a few more connectors to hold the other electronic elements, but for now, I just want the grid array with a 5 conductor link (VCC/GND/DATA/CS/CLK) that I can connect using I2C to whatever microcontroller.
You can see the in-wall toilet tank here (TOTO).
The small valve to the right of the red tank frame is a slow drip to the in-floor trap. This keeps the trap filled even when the floor drain isn’t often used. It will prevent bad odor from coming up through a dry trap.
I’m the son of a farmer and although trained in engineering principles, I usually like to over-engineer things for additional strength.
Here we’re filling the walls with concrete to unite the bricks and reinforcing steel into a single structure.