The purpose of this timer is to provide a countdown time from 1 second to 99 minutes & 59 seconds. I use it to control the lighting for the Ultra-Violet exposure of photosensitive PCB material. The project provides also an audible alarm at the end of the countdown time and switches the UV lights by means of a relay. It is based on a Microchip microcontroller, the 18 pin PIC16F84(A). This microcontroller contains 1Kbyte of flash memory for program code, 64bytes of static RAM memory, and 64bytes of EEPROM memory which are used here to store up to 15 different (user-programmable) countdown times.
PIC16F84 Countdown timer for PCB exposure unit: [Link]
The basic idea of TinyProjector is to create the smallest possible character projector that can be either integrated into mobile device, or linked dynamically with wireless RF connections like serial low range transceivers. Compared to all the earlier versions, which used laser diodes salvaged from cheap key chain laser pointers, the current prototype has smaller low-cost low-output laser diodes that allow for just one row of eight lasers instead of two interlinked rows of four lasers, making cumbersome primary deflection mirrors obsolete.
Tiny LED Projector: [Link]
This project is a simple 12-bit, 8-channel analog to digital converter (with 4 additional digital inputs), which may be connected to the PC through the serial interface (RS232). The sequence of sampled channels, and sampling frequence are programmed by the PC while the maximal sampling frequency is limited by the data transmission rate, and at 115200 baud is equal to ca. 3kHz for 1 channel without digital inputs, and to ca. 500 Hz for 8 channel with digital inputs.
The analog input voltage range is -2.5V to 2.5V. The digital inputs may be used for recording additional digital signals, eg. the time code used to synchronize the recorded data with other events. The project is based on PIC16F84 (or 166C84) microcontroller, and MAX190 (or MAX191) ADC. The device is mounted on a small single-sided printed circuit board, easy to prepare even at home.
PIC16F84 12-bit, 8-channel analog to digital converter: [Link]
This PIC16F84 based decoder can detect and display on its LCD the exact code that is sent in the IR signal. The project uses two types of IR receivers one for 36 KHz and one for 38 KHz, this ensures adequate sensitivity for all supported protocols.
PIC Based IR Decoder: [Via] - [Link]
Red digits on this photo appear to float in the air in front of the clock. This illusion is based on inertia of a human eye. If LED-formed digits will periodically and frequently enough flash, they will appear solid and steady. And since the matrix of digits is formed by a mechanically scanned single line of LEDs, and the fast rotating clock body is not visible, it leaves digits “suspended” in the air.
The first clock using this concept was built (and PIC microcontroller code written) by Bob Blick, please visit his page for yet more photos of his original clock and clocks built by other people. The heart of this clock is PIC16F84 microcontroller. (Older PIC16C84 version works just fine). The microcontroller is programmed with the code provided below. If you don’t have a PIC programmer, it isn’t difficult to make one. A few parts (for a couple bucks) connected to the parallel port of your PC will program the PIC for you.
POV clock based on PIC16F84: [Link]
