SKIF_PI-AUTOtune on ATiny2313-10 microcontroller
Skif PI Auto Tune V3.2 sch mod by Tilikum.RU
By sevzirfo My version of the universal pulse metal detector for the most severe operating conditions. A feature of the scheme is the presence of an asymmetrical slow auto-tuning zero offset, the use which allowed to get rid of the slow drift of the sound threshold and always search for the highest possible sensitivity When operating in the absence of a target, the detector emits a slow crackle, like a geiger counter, and when a target is detected, it sharply increases the frequency of the sound. With a long hovering over the target, the auto-tuning SLOWLY compensates imbalance and the frequency of the sound decreases to rare crackles, but if the coil is removed from the target, FAST reverse compensation occurs (the recovery rate is 5 times higher) and the detector will be ready for further searching. When changing coils of different sizes, the detector adjusts itself for them - auto balance coil feature, to speed up this process, the "FAST TUNE ZERO" button is provided. For a visual indication of the auto-tuning operation, a VD4 LED is displayed, which blinks periodically when the auto-tuning feature is working and the detector was set for maximum sensitivity. Search coils from 18cm to 3x3m were tested, with a square frame of 1x1 meters confident detection depth was 3.5 meters (target was automobile). Version 3.2 of the program for the ATiny2313-10 microcontroller (work at 10 MHz). Added steps (7 steps) adjustment of the pause duration before the sampling pulse (guard interval) for cutting off small objects without loss of sensitivity for large targets. Applicable to search coils of any sizes. If you search small golden targets you should make fast, low-capacitance coil. For steps switching, the controller free terminals are involved. To tune guard interval switch any of these pins of the controller must be closed to minus constantly, output polling occurs when you press the reset button. |

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