AVR frequency meter – from 1Hz to 10MHz

Frequency meter with some of quite good performance, capable of measuring frequencies from 1Hz to 10MHz (9,999,999 Hz) with a resolution of 1 Hz over the entire range. Ideal for function generators or as a standalone meter. It is cheap and easy to make, with parts that can be bought anywhere, and with a small size that allow it to be mounted in the panel on any device.

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4x100W car audio amplifier

400W car power amplifier. Based on a push-pull converter with TL494 (KA7500) driver, 500W of power is enough for four TDA7294 integrated amplifiers. Three three-digit multimeters on front-panel shows actual battery voltage, temperature, and estimated output power.

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Nie-zwykła żarówka – RGB

The “not-ordinary bulb”, as title say, typical glass and metal bulb with electronic inside. Powered from miniature AC-DC converter – i have used that one from 230-5V USB chargers – it has enough power (about 500mA) for few RGB leds. Next is Attiny13 (SOIC8 package) based RGB driver, it not only can change colors, but has 3 modes and an automatic color and mode saving to eeprom memory – so after power up you always will see last seen mode and color.

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Elektronic business card 85 LED

Electronic business card / scroll display. 85 SMD 0805 led’s matrix display, Atmega88V uController, and couple of other smd parts. Dimensions are 24mm x 85mm, supplied from 3V small coin battery. It will work for long time, even on discharged battery (2V). After button is pressed, device is waking-up from power-down mode and start scrolling text equivalent to pressed button. 4 text’s are saved in eeprom memory, each one can be 127 character length (128 cell is used for holding special end-char).

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Interactive mug coaster

Interactive mug coaster, thanks to analog temperature sensor LM35 and uC builded-in analog-digital converter, device can read temperature from standing on it glass. Device calculates temperature and smoothly light-up our drink with slowly changed RGB colours. When temperature is under 20*C then displayed colors are cold, and when temperature is above 28*C then colors are hot. When nothing stands on device (temperatures from 20*C to 28*C) then it automatically swich off. Fusebits are: 4,8Hz internal clock, not divided by 8. Supply voltage is stabilized by 1117 type stabilizer to 3.6V. The red LED requires lower voltage, and current on that…

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