Here I present to you a single AA battery led circuit. This circuit is a variant of the Joule thief in that it contains 2 transistors and a simple standard 2 lead inductor instead of a hand wound 2 wire inductor.
You can use it as a white led torch. You can use a fresh AA battery, but the circuit is special in that it accepts empty batteries. Down to 0.7 volts. Do you have a box of empty batteries? They are still useful to power this led circuit. Continue reading
This random timer circuit is based on a Atmel ATTINY24 avr driving one power relay. You can use this circuit to switch on and off other circuits randomly. For example, when using this circuit on a model railroad you can turn on and off parts of the animated or moving scenery to create a more dynamic view.
This circuit was designed to be used on a modular model railroad. This model railroad contains different flashing light on ambulances, police cars and fire engines. These lights are on all the time, with this circuit I hope to keep visitors of a model railroad exposition more interested while watching all the action. Continue reading
I made some progress with building my led clock.Â In the video you can see 80 74hc595 shift registers driving 80 7 segment led displays. The bottom row works, but has no data yet to display. You can see: unix timestamp, day of week, weeknumber, date, new earth time, swatch internet time, hexadecimal time, French revolution decimal time, approximate local solar time and local time.
Soldering a lot of SMD leds? Never sure what polarity the smd led has? Make this simple SMD LED tester.
Take a look in your used battery box and search for a 9V PP3 battery. Solder any resistor with a value between 470 ohms and 10K onto the battery terminals. Continue reading
I am busy testing a modular 7-segment led clock. Each module can contain up to 3 pieces of 7-segment led displays driven by a 74HC595D shift register. Modules can be combined into larger strings.
In the video the modules are driven by an Arduino Nano 3.0 using the SPI interface. Continue reading
This tiny DCC decoder has been made to drive 8 leds. Instead of using a more expensive turnout decoder this may be a nice alternative.
Here a video of a blue version of the double led dice. Want to build it yourself? Click here fore more information.
Try making a double led dice with 14 leds driven only by 4 available pins of an Atmel Attiny13a. I did it, and it worked. See the result in this video.