Ultrasonic Motion Detector

This is a ultrasonic motion detector (or movement detector) circuit. The circuit claimed has a high movement sensitivity. Even air moving (hot air rising, wind blowing) will trigger it when the trimpot is set near the most sensitive position. The transmitter sends out a steady ultrasonic tone at 40kHz. At this frequency the wavelength is… Read More »

DOD FX75 Flanger Guitar Effect Pedal

This is the circuit diagram of DOD FX75 Flanger guitar effect pedal. The circuit drawn by Fabian P. Hartery. Featuring a Width control and two output jacks, the FX75 was much more versatile than its predecessor, but the flanging effect it could provide was still not very intense. That said, chorus-like washes of flange can… Read More »

5V Regulated Solar Cell Power Supply

Powered with solar panel, the circuit will give you 5V pure regulated DC voltage. This solar cell power supply circuit is made up of an oscillator transistor as well as a regulator transistor. The solar panel charges the battery when sunlight is bright enough to generate a voltage above 1.9v. A diode is necessary between… Read More »

Easy Build Motorcycle Alarm

The following circuit is a simple, cheap and easy build motorcycle alarm. The circuit just required 2 transistors to drive the relay the the relay act as a switch to activate the buzzer. Any number of normally-open switches may possibly be applied. Fit the mercury switches to ensure that they close when the steering is… Read More »

Electro Harmonix Graphic Equalizer

This is the diagram od electro-harmonix graphic equalizer. You can specify the number of channels according to your needs. You just need to parallel the components: C1, C2, R1, an om-amp, Potensiometer and a 470 ohm resistor. The frequency to be boost decided by C1, C2 and R1. See the diagram for the C1, C2… Read More »

3-Rail (+12V) / (+5V) / (-5V) Regulated Power Supply

This circuit generates 3 source regulated voltages applying a minimum of electronic parts. The output DC voltage are +12V ; +5V and -5V. Diodes D2 and D3 conduct full-wave rectification, at the same time charging capacitor C2 on each halves of the alternating current cycle. At the same time, diode D1 with capacitor C1, and… Read More »

Sound Effect Generator UM3561

This is a really simple sound effect generator based single sound generator chip UM3561. The UM3561 will generate four kinds of sound effects. The basic operation is that the UM3561 will generate the sound signal, then the signal delivered to 2N3706 (as speaker driver) to be amplified so you can hear the sound from a… Read More »