This project demonstrates a simple laser projector made with 25 dot laser diodes driven by a hacked micro:bit. It is a wearable device to project text messages on any flat surface.
As for the programming part, Ada is used to program the micro:bit board to generate text massage with the lasers. The Compiler/IDE used for the programming is GNAT Studio from AdaCore.Application DemonstrationStep 1: Hardware Layout
25 Optocouplers are placed on a protoboard and soldered (+micro:bit).
Onboard 25 LEDs are removed and polarity is identified as follows for wiring to the Optocouplers inputs. ( "-" to Cathode and "+" to Anode )
A protoboard is added to breakout the I/O pins of micro:bit for future development.
Original Idea was to use 25 Laser diodes but 20 Lasers (4 Columns) is enough to display and project scrolling text.
After few episodes of painful soldering -
Step 1: Installing GNAT Studio, Drivers and Examples
From this link : https://www.adacore.com/download, following two exe files are downloaded and installed on a Windows PC.
Step 2: Open Example Project
Run GPS (GNAT Programming Studio)
Open board specific example code from following location:
Step 3: Modify Example Project
In the main.adb tab:
Change following code
with Display; procedure Main is begin loop Display.Scroll_Text ("Make with Ada! "); end loop; end Main;
with Display; procedure Main is begin loop Display.Scroll_Text ("Hacked With Ada "); end loop; end Main;
Step 4: Flash on Micro:bit
- Advertisement during exhibition
- LOS visual communication
- Showoff Geek badge !
- Add BLE for uploading message
- IoT Connectivity to nRF Cloud
- Driving and sensing with unused I/O pins
The hardest part of this project was to align the laser beams. It's literally a nightmare. Beware of that ! (Also, soldering 200+ joints was a huge pain)
Following "+" code can be used to align the beams against the center beam to adjust dot spacing and angular position.