New version (Beta):
In this version this metal detector works with a smartphone or without a smartphone with the possibility of adding an LCD screen. Now Spirit Pi is more stable and reaches more depth. The diagram and the PCB can be found below, also in the file you will download will be gerber file in case someone wants to order the PCB on the JLCPCB page. JLCPCB is a page where we can order the PCBs we want for a very low price, we just have to upload gerber file of the circuit and that’s it.
News:
Now in this detector we have 3 buttons: “+”, “-“, and the “M” menu. With these buttons we can adjust the pulse width, sensitivity and frequency. Instead of the TL072 amplifiers we will use NE5532. The micro controller will use an Arduino nano. The coil is still 25 turns with 0.5 mm wire and the radius 20 cm.
Components:
The components I usually buy on Aliexpress for the low price. In this way we can make a good metal detector and spend little money. Below I will leave the links where you can buy these components to make this metal detector!
have you solved? Now working?
I haven’t been able to get the metal detector to work yet. Now I have had time to try again and I have visualized the waveform coming out from the arduino. Instead of being perfectly square it has a big negative peak right after the positive one. I also tried another arduino (also disconnected from the rest of the circuit) but the waveform does not change. You can help me?
hello, dear electronics engineer, I found your Spirit Pi circuit and thought I would rebuild it completely. Unfortunately, I would like to have an exact specification of the assembly of the board. I mean which components belong where. Maybe you can show me a photo in detail where I bring exactly which component. Sincerely, Juergen
Hola querido ingeniero electrónico, ¿cómo se flasheó exactamente la placa esp32 con qué cargador de arranque y qué firmware? Pide tu ayuda También estoy dispuesto a enviarte una donación.
I have made your project Spirit PI ESP32 version 2.0.0. The part before ESP32 works great (I checked the signal at the output of the operational amplifier which changes when there is metal near the coil. When I turn on the application, I connect and pair successfully with the “ESP32_Spirit_PI-2” Bluetooth device, but when I press the refresh button on the smartphone, the application disappears from the screen (or on older Android the message Spirit pi has stopped appears). Please help
I have made your project Spirit PI ESP32 version 2.0.0. The part before ESP32 works great (I checked the signal at the output of the operational amplifier which changes when there is metal near the coil. When I turn on the application, I connect and pair successfully with the “ESP32_Spirit_PI-2” Bluetooth device, but when I press the refresh button on the smartphone, the application disappears from the screen (or on older Android the message Spirit pi has stopped appears). Please help.
Hallo ich bin gerade dabei deinen Matalldetektor Spirit Pi 4pro nachzubauen. Ich hätte eine Frage zum Wiederstand R25 230k würde auch ein 220k funktionieren? Die 2.Frage bezieht sich auf R28 Kann es sein das dort ein 4,6ohm Wiederstand anstatt ein 46ohm Wiederstand hin kommt? Ich bin noch Anfänger und würde mich freuen wenn du mir Helfen könntest. VG. Markus