Overview Batwatch is a simple monitor for a solar panel battery charger, using an Atmel ATtiny13V. It periodically measures the charge current and battery voltage, and shows them by blinking two LEDs. I built this circuit into the plug of a VW solar charger panel that is used to prevent a discharge of the battery […]
Batwatch using ATtiny13V microcontroller Read More »
Introduction: My project is a self-powered solar data logger. Put out in the sunlight, it will measure the light level and log this to memory to be later downloaded to a computer. The system is powered by a small solar panel and battery. Summary: The solar logger I built uses a photodiode to measure the
Self-powered solar data logger using ATmega32 Read More »
Based on the Atmel ATtiny12L-4PI microcontroller -A real Time Clock/Calendar for less than US$1.50 in moderate quantity. This is the timekeeping test circuit. It includes a one-transistor circuit to switch in the 5V power supply when present and drop back to the 3v battery the rest of the time. That loop of blue wire-wrapping wire
Overview Where I live most of the time, the AC power drops out upon occasion. This used to leave me groping around in the dark for a flashlight. I could have bought a battery-backed up “emergency light” for about US$35, but being basically metal boxes with floodlights attached, they would make my living room look
White LED Battery Powered Power Failure Light Read More »
Photo. This is the test circuit -the basic driver is only two transistors, two resistors, the circuit was evaluated using a white LED, but when it was time to button it up and archive it, I replaced the expensive white LED with a cheap green one. Othere LED Driver Circuits on this site: White LED
Series Connected Voltage Boost Circuit for a Battery Operated LED Lantern Read More »
Three inductor-free circuits that allow a white LED or UV LED to be driven from one (1.5 volt) or two flashlight cells (3 volts total) are described. The circuits on this page are: The two cell (3 volt) circuit four transistors. The simple single cell (1.5 volt) circuit requires six transistors, but it isn’t as
Single and Two Cell White LED Drivers Without Inductors Read More »
Download FreePC project file, gerber and png copper and silk-screen: 1wattledbuck.zip Introduction I have some 1 watt warm white LEDs left over from a project and the application for them was obvious: A better battery operated lamp for use when the power fails, which it does frequently, especially during the rainy season. And this one should
1 Watt White LED Power Supply Circuit for battery operation Read More »
The “Battery Good” checker. When the button is pressed, the green LED will glow if the battery voltage is above the preset threshold. This version has a higher parts count than the “Battery Low” version, but a bonus is that it can drive an LED to be very bright, and the luminance is independent of
Battery Checker Circuits using microcontroller Read More »
The project allows you to analyze characteristics of unknown/junk battery especially the capacity and variation of the voltage on discharge. It is controlled with a PC via a serial port. No external power supply is required because it is powered by RS-232C signals. It uses ATmega48 as main controller for dummy load and constant current
Simple Automatic Battery Discharge Analyzer using ATmega48 microcontroller Read More »
The Joule Thief is such an easy and simple device, but what it does is amazing. It can use a battery that is not usable in any other electronic device and give it life again. It can even take a battery that won’t even power a basic LED by itself when it is brand new
The simple joule thief using AVR microcontrollers Read More »
