PSoC Polyphonic Piano
Cypress Microsystems released a new family of microprocessors
some time ago called the PSoC family. These devices are like Lego
building blocks for engineers. The development tools are powerful
and inexpensive. Here is one o...
White LED Flashlight
I took my car to a mechanic recently and while inspecting the
seal around the oil pan, he pulled out a small penlight that put
out what appeared to be "white" light. When he showed it to me I
realized the light was coming fro...
Heartbeat Monitor (HeMon)
Here is a circuit from Keith Wilson in
Germany for monitoring your heart. The text that follows is
The heartbeat monitor was originally designed many years
One day whilst walking through the town centre in M...
Low Cost Hearing Aids
For me, the realization came about seven years ago. My wife, who
was sitting to my left, asked me, "Are you going to answer that?"
As I turned my head to look at her I began to hear the phone
ringing behind me. That was the ...
Build your own Gaussmeter
Here's an nifty little project from the Magnet Man, Rick
Hoadley. The original can be seen at his home page.
Have you ever wanted to find out how strong a magnet really was,
or how the strength of the magnetic field vari...
Cranial Electrotherapy Stimulator
This design came from RED Free Circuit Designs. According to the
information associated with this schematic:
"CES is the most popular technique for electrically boosting
brain power, and has long been prescribed...
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 b...
This circuit is an AC-powered current source designed for
recharging batteries. It can crank out as much as 1 amp and can be
modified to go even higher by choosing different devices for Q1.
Since this circuit uses AC line voltages...
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...