After I finished the CycleLux Project, my father-in-law was interested in my building a light bar for his Polaris RZR ATV. The finished product incorporates 336 high power 5mm LEDs with a control circuit capable of dimming and features strobe and various chase operational modes. The entire circuit runs off of the 12V battery found on an ATV.
When an old friend commissioned me to make him a Jeopardy style game controller to be used in his high school science classes, I got to work on a full system complete with speaker, LEDs, timer display, and four player buzzers - all enclosed in an old briefcase. The system passed TSA screenings and survived a 2000 mile flight from CA to IL tucked away in my checked bag...
After starting and stopping multiple projects due to inadequate testing methods, I decided to design a manual controller for testing data bus devices. It receives user input and sends the data out on the appropriate bus pins to test specific functionality of some attached circuit.
This circuit was designed and created to control and drive a bank of LEDs in response to a touch sensor. It is controlled by an ATtiny25 MCU and uses a constant current source.
I use LEDs in almost all of my designs. Most of the time, a simple series resistor is sufficient for driving current through the LED, but often, a constant current source is the way to go.
This circuit was designed and created to control and drive the LEDs in the CycleLux bicycle lighting system. The current version uses an ATtiny25 MCU to communicate through an MCP23S17 I/O expander to a bank of MOSFETs driving the LEDs.
Many times, I am in need of a quick way to test the output state of a digital circuit or want a definite HI or LO input. That is where this circuit comes in. Eight dip switches serve as logical high and low outputs while an LED array displays green for high inputs and red for low ones.