Showing posts with label pic. Show all posts
Showing posts with label pic. Show all posts
Saturday, October 4, 2014
Phone Alarm Dialer using MT8880 and PIC 16F84A
Phone Alarm Dialer using MT8880 and PIC 16F84AJust angle this Anxiety Buzz Dialer up to article you would like to monitor, for example, a aerial baptize alarm, low temperature alarm, aback window, barn door, etc. Back the arrangement is activated it will anxiety a cardinal of programmed numbers to let you apperceive the anxiety has been activated. This would be abundant to get alerts of anxiety altitude from your home back you are at work.
The ambit uses a MT8880 DTMF dialer dent and a PIC 16F84A microcontroller. After putting calm this little device, you charge access programming-mode to apprentice some buzz numbers which this bore will anxiety afterwards audition an ascribe on it’s sensor pin.
After programming aloof accumulation ability to the device. Afterwards acute the button “Pokreni dojavu alarma” it will alpha to punch (tone or pulse, depending on the jumper setup). Back the buzz anxiety is auspiciously established, the alleged affair should columnist batter key “#” to stop the accessory from calling addition cardinal or again.
Sunday, April 7, 2013
USB Powered PIC Programmer
This simple circuit can be used to program the PIC16F84 and similar "flash memory" type parts. It uses a cheap 555 timer IC to generate the programming voltage from a +5V rail, allowing the circuit to be powered from a computer’s USB port. The 555 timer (IC1) is configured as a free-running oscillator, with a frequency of about 6.5kHz. The output of the timer drives four 100nF capacitors and 1N4148 diodes wir-ed in a Cockroft-Walton voltage multiplier configuration.
Circuit diagram:
USB-Powered PIC Programmer Circuit Diagram
The output of the multiplier is switched through to the MCLR/Vpp pin of the PIC during programming via a 4N28 optocoupler. Diodes ZD1 and D5 between the MCLR/Vpp pin and ground clamp the output of the multiplier to about 13.6V, ensuring that the maximum input voltage (Vihh) of the PIC is not exceeded. A 100kΩ resistor pulls the pin down to a valid logic low level (Vil) when the optocoupler is not conducting. The circuit is compatible with the popular "JDM" programmer, so can be used with supporting software such as "ICProg" (see http://www.ic-prog.com).
Author: Luke Weston - Copyright: Silicon Chip Electronics
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