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1. 555 Timer Missing Pulse Detector Circuit.
This circuit is a missing pulse detector. It is used in the_ General Purpose Controller Board with Basic Stamp 1.This circuit is used to monitor an input pulse train, and when a pulse is missed the 555 timer output will switch low. For the General Purpose Controller Board the input pulses are provided from an IR sensor salvaged from an old VCR. An "All In One Remote" is used to trigger the IR sensor continuously by clamping one of the remote buttons down, which causes the remote to transmit continuously. When the IR beam is broken by someone walking past it the missing pulse circuit produces an output to the Basic Stamp. R2 must be adjusted differently for different buttons on the remote.
2. 555 Timer Led Flasher Circuit.
This is a simple LED flasher. R1 adjusts the frequency of the flasher. Change R1, R2, and C1 for different frequency ranges.
3. 555 Timer Toy Organ Circuit.
This is a 555 timer used as a toy organ. Add additional switches and capacitors if desired.
4. 555 Timer Star Trek Red Alert Circuit.
This is a circuit which makes the Star Trek Red Alert sound.
Circuit Description
To hear a sample of the sound it makes click here.
5. Audio Amplifier Circuit.
A simple audio amplifier using a 741 op amp and an LM386 amplifier chip.
6. Function Generator Circuit.
A function generator which provides square wave, triangle waveform and sine wave outputs. Requires two 1458 amplifier circuits.
7. LM3914 LED Bar Graph Circuit.
An LED bar graph display using an LM3914 chip.
8. Transistor Dual LED Flasher Circuit.
An LED flasher the old fashioned way, with transistors !!
9. Transistor Audio Mixer Circuit.
Design Equations:
Current Gain = R6/R8
Input Impedance approx. R6
Output Impedance approx. R7
10. Transistor Light Flasher Circuit.
A light flasher using transistors rather than a 555 timer.
11. Motor Direction and Speed Control Circuit.
A motor speed and direction control circuit. The direction control is done via an H bridge using IRF511 MOSFETS. The speed control is done using a 555 timer and an IRF511 MOSFET.
