All posts on October, 2008



AT89LP2052 and AT89LP4052 Parallel Port Programmer

 

AT89LP2052 / AT89LP4052 Parallel Port Programmer
This 2052 / 4052 programmerย�design uses the parallel programming mode via Parallel Port. Only parallel programming can re-enable the ISP Fuse. This programmer is alsoย�usefull if you need to write the user fuses to disable the XTAL Osc Bypass fuseย�-ย� e.g. toย�test the LP2052ย�in existing 2051 hardware designs.[more]

Posted in : MCS-51 projects

DIY CLASS A MOSFET HEADPHONE AMPLIFIER

 

DIY CLASS A MOSFET HEADPHONE AMPLIFIER
This is a simple do-it-yourself (DIY) headphone amplifier project that is fashioned primarily after the Class A MOSFET Headphone Driver project by Greg Szekeres and to some extent Mark’s DIY Class A 2SK1058 MOSFET Amplifier Project. The amplifier concept is simple and follows a typical single-ended class A circuit utilizing an active constant current source (CCS) in place of a passive resistor. A CCS doubles the efficiency of the circuit over that where a passive load resistor is used, bringing it to a maximum of 25%.[more]


Posted in : Amplifier projects

Servo Tester Module

 

Servo Tester Module
The board uses a PIC16F690, with the code written in C. The timing loop is a crude one relying on a simple tight loop, so the pulses are not massively accurate.The board has four modes of operation, selected using TACT switches with the status indicated on LEDS built into the switches .[more]

Posted in : Radio control projects

SMARTLOCK

 

SMARTLOCK
The SmartLock provides two external controls for the SG-230. A locking function prevents automatic retuning despite changing antenna loads (eg. from passing trucks or passing beneath bridges when mobile). A reset function forces the Smartuner into a retune cycle until the signal is transmitted again, or allows receiver/scan in a broadband antenna mode. A ‘tuned’ led also indicates locally when the SGC-230 achieves a match.[more]

Posted in : Sensor projects

Electronic Temperature-Controlled Relay

 

Electronic Temperature-Controlled Relay
The heart of the circuit is the LM35 temperature sensor which is factory-calibrated in the Celsius (or Centigrade) scale with a linear Degree->Volt conversion function. The output voltage changes with temperature from 550mV (-55oC) to 1500mV (150oC). This greatly simplifies the thermostat designed only need to provide a precision voltage reference (TL431) and an accurate comparator (A1 of LM358) in order to construct a complete thermostat.[more]


Posted in : temperature control

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