This post outlines the process of adding the two ultrasonic sensors to the shelf sectioj of my project
With the LEDs in place and the circuit-board built, I needed to test them out to make sure they were working!
I’m using transistors to ground each group of LEDs, so a field of 30 transistors was needed. The transistors being used are 2N4401s. The collector of each transistor is connected to ground, the base to the arduino, and the emitter to the LED group (via a 39 ohm resistor).
With the LEDs in place, the next step was to get them soldered together. The circuit works with positive legs of each LED joined together, and running off a 5V supply. The ground legs of the LEDs are joined in groups of 4, and these are grounded via a transistor when required.
This is the process, with pictures, of how the LEDs were put onto the back board.
With the booth build and covered, the next step was to add the two lines of LEDs. To make sure this went smoothly, and not to ruin my frame, I decided to build a prototype version first, where I could test out the process of putting the LEDs onto the back board.
The shelf on my project will hold the two ultrasonic sensors and the through-beam proxistor sensor. It is 90cm high and 15cm thick.