This homemade metal detector circuit will help you find objects composed of materials with relatively high magnetic permeability. It is not suitable for buried coins discovery that is not sensitive enough but you can detect pirates treasures!... Read more »
Here is the schematic of my capacitor meter I built and have used quite a bit. It will measure from zero to 0.1uf with 300pf at mid range. ... Read more »
Here is a digital Ammeter based on PIC16F684 and ACS712 current sensor. The measured DC or AC current will display on 3 digits 7-segment with resolution 100 mA. The current sensor in this project is ACS712ELCTR-30A-T from Allegro(I got from ebay). It can measure the AC or DC current up to 30A with 66 mV/A output sensitivity.... Read more »
This multimeter was designed to measure output voltage and current in a PSU, where the current sense shunt resistor is connected in series with load at the negative voltage rail. It needs only one supply voltage that can be acquired from main PSU. An additional function of the multimeter is that it can control (switch on and off) an electric fan used to cool the main heatsink. The power threshold at which the fan switches on can be adjusted using One Touch Button Setup.
... Read more »
This homemade metal detector circuit will help you find objects composed of materials with relatively high magnetic permeability. It is not suitable for buried coins discovery that is not sensitive enough but you can detect pirates treasures!
Here is the schematic of my capacitor meter I built and have used quite a bit. It will measure from zero to 0.1uf with 300pf at mid range. 
This simple water detector circuit uses alternative voltage in order to prevent the corrosion of the electrodes. 
This multimeter was designed to measure output voltage and current in a PSU, where the current sense shunt resistor is connected in series with load at the negative voltage rail. It needs only one supply voltage that can be acquired from main PSU. An additional function of the multimeter is that it can control (switch on and off) an electric fan used to cool the main heatsink. The power threshold at which the fan switches on can be adjusted using One Touch Button Setup.
