Schematics / Electro-Optics
LED Turn Signals
Seen those cars with fancy turn signals on their side view mirrors? Would you like to add something like that without buying a new car? Well, this circuit takes that idea a step further by generating a sequence of moving chevrons to create an animated turn signal. And, the circuit uses common logic devices instead of a microprocessor so no device programming is required....
SPI Interface Big 7-Seg LED
Easy build and use, the general purpose Big LED with SPI serial interfacing. Expandable for multiple digits but still uses only three wires for receiving data from any uC boards. ...
Universal Programmable Remote
Enter the Project Commander! This universal remote works with virtually any IR remote. It "learns" by sampling an IR signal coming from any remote by using the built in 10 bit SAR A/D. These IR settings are then stored internally in the Virtual EEPROM....
Bicycle Safety Light
This circuit has been designed to provide a clearly visible light, formed by 13 high efficiency flashing LEDs arranged in a pseudo-rotating order. Due to low voltage, low drain battery operation and small size, the device is suitable for mounting on bicycles as a back light, or to put on by jogger/walkers....
Rugged LED Brake Lights
OK, here's a simple circuit that was by requested by a reader. Normally, I don't like to run too many LED's in series because if one dies, the whole string goes out. Finding the dead one can be bit problematic as well. So, in this design, Super Bright red LED's designed to run at 40mA were used. But to decrease the chances of failure, I'm only running them at 20mA....
UV Sensitive Photodetector
A UV sensitive photodetector can be realized by using a Siemens BPW34B with a standard transimpedance amplifier. The enclosed schematic shows two different circuits. The circuit on the left is a basic design which can be used for detecting a slowly changing source. Because it is sensitive down to DC, it will also amplify any dark current from the PIN diode as well as ambient light....
Optoelectronics Circuit Suite 
The following collection of analog circuits may be useful in electro-optics applications such as optical networking systems. This page summarizes their salient characteristics....
LED Amplifier
I recently built a new PC and noticed after I was done that the hard disk light was almost impossible to see. I tried different LED's that were more efficient and even thought about modifying the motherboard. But, I decided to avoid that risk and make things interesting by designing this circuit instead....
LED Lamp Dimmer
This circuit provides 32 steps of brightness control from 0 to 100% for a backlight or instrument panel using just two general purpose microprocessor signals. In addition, very little board space is required since only three SOT23's and a uMax package are used....