Posted on 08 Aug 2008
A keyboard is a central part of any synthesizer and this is a good keyboard circuit. It is monophonic in function i.e. its a single note keyboard. It performs the function of translating key presses into appropriate voltages so that you get 1V/Octave or .08333 volts per semitone. It also provides gate and trigger signals. The gate goes high when you press any key and remains high until all keys are released. The trigger emits a pulse (approximately 1 to 2 mS) each time a note is pressed or changed. [more]
Posted on 08 Aug 2008
The PC Printer Port Interface presented here allows a significant number of data latches, or ports to be controlled from a single PC parallel / printer port. Standard and bidirectional ports are supported. Enhanced ports are not required. Fully expanded, and with 8 bit latches connected to each sub-address, it is possible to address 1024 individual 1 bit lines, for turning on or off lights, motors or whatever. [more]
Posted on 08 Aug 2008
It uses only 4 chips - 3 HC TTL’s and an Atmel At90S2313 microcontroller. It has a 5 digit LED display plus one used as a band indicator.the current consumption is less than 50 mA.It counts up to at least 52 MHz.The schematic is quite straightforward. There are two major parts, the display multiplexing and the counter stage.[more]
Posted on 08 Aug 2008
This is a simple circuit for DC Motor speed control (fan speed control, light dimming and etc) using the 555 timer. Also a good starting point for novices wanting to get their hands dirty with the 555 timer IC. Some would argue that this is not the most efficient approach.[more]
Posted on 08 Aug 2008
The Lux Meter is usually used to measure illumination. The illumination is how level of luminous flux is falling on a surface area. The luminous flux is visible component that is defined in radiant flux (light power) divided by relative sensitivity of human eyes over the visible spectrum. This means the Lux is well fit to light level from sense of human eyes.[more]
