This project was started by friend of mine, viagra online price iframe who wanted to make this circuit for school assignment. He found some schematics of analog section on internet, microcontroller section designed by him self, but circuit didn’t work. Many of those “internet” schematics works, but only if You use same or equivalent components (talking about semiconductor components here) as noted on schematic, also good solder joints are imperative.
Debugging oscillator without oscilloscope is very hard, in some cases impossible. Oscillator is buying viagra in tijuana crucial part of any kind of metal detector. If You aren’t familiar with these devices, there are two major technologies; first is inductive which measures changes in magnetic field, second is sonar type which measures inductance pulse, You can find more detailed description on wikipedia. Sonar type detector requires specially wrapped coil, so i decided to make simple oscillator and viagra cost walmart measure number of impulses per second (frequency), since its only required functionality was simply to detect piece of metal (100 x 80 mm).
Shortly after few attempts to fix his circuit i gave up and took universal board, assembled simple oscillator which you can see on schematic bellow. Oscillator consists of T1, R1, C1 and L1, other components converts sine signal to TTL logical levels which microcontroller can detect. Microcontroller board is viagra sales numbers my development board for ATtinyx61 (261, 461, 861 series) with only ISP and alphanumerical display ports on board which i patched to oscillator board. Few minutes later firmware was done.
Oscillator frequency is approximately 130kHz, if You wonder why exactly this frequency, there are no any special reason except it started to oscillate at this frequency when i switched on power supply. :) When piece of metal gets close to coil frequency goes up to 160kHz which is viagra pfizer india more then enough to detect presence of metal.
Coli is wrapped around ferrite core from old 150uH SMD inductor; approximately 30 turns of 0.55 mm wire.
More info on microcontroller board will be posted soon!