After days of experimenting, it was time to move from breadboard to circuit board.
Most of my projects follow the pattern of idea to prototype Breadboards are ideal for a prototype. They contain rows and columns of holes into which you mount parts. Then you attach small jumpers to wire the circuit together. This general approach works well for low power control circuits.
The main components of the controller for my Magnetic Loop Antenna are an Arduino microcontroller, a ULN2003 stepper motor driver and an ESP8266-01 WiFi module. These are shown at the left, center and right of the breadboard above. Also shown above is the MB102 breadboard power supply, which is providing 3.3 volts on the top rail, and 5.0 volts on the lower rail. This Arduino model and the WiFi device use 3.3 volts, while the stepper controller needs the higher voltage.
Once the loop controller was proven to work, it was time to go from breadboard to board, shown in the right hand picture. No more rats nest of wires. I transferred the design and etched the PCB pretty quickly. Since the WiFi and motor drivers use a lot of current, I made sure to etch wider traces for power and ground on the circuit board.
From Breadboard to Circuit Board – A Better Power Supply
While testing things on the breadboard, I had a lot of trouble with the WiFi module failing. I noticed that when it failed, the on-board LED would dim. This made me think that either my power supply was not working properly, or the metal traces/jumper wires on the breadboard were not up to the current (400 ma.) I never did figure out which, but switching to a bench power supply for the WiFi card solved the problem.
In the final design, I used an LM1117 3.3V voltage regulator to power the WiFi. The Arduino and ULN2003 will run off 5 – 12 volts provided to the PCB. The LM1117 then provides the lower voltage to the WiFi, as shown in this diagram.