Some more photos of boxed Clone PI AVR metal detector and self made coil. I have made a coil from Ethernet cable between two round plywood sheets filled with Makroflex sealant. More about making coil from Ethernet cable can be fount here. Idea how to seal everything came from here. Clone PI AVR intself was boxed in a box I bought in local electronics store. I decided to add a switch to switch off external beeper so that sound will be provided only through headphone socket. For the coil connector I have selected some two pin microphone connector. I think in general it came up pretty well. Will be mounting everything on appropriately bent and painted PVC pipe. Will post pictures later. Some day. Probably.
Some years ago a have started building Clone PI AVR. Made a PCB, soldered all the components and ... and never found time to finish it until today. Well I haven't finished it yet but at lest gave it a first test run. For the screen and buttons i have re-purposed some front panel of some old router. Now i see that i will have to put it in to another box for better mounting on the metal detector itself but this time it was good enough for test run. For Atmega programming I used Mini Pro TL866 programmer I have bought while ago - works like a charm. You can see some photos and video on work in progress. https://www.youtube.com/watch?v=VZVZoRKr3T8 Circuit of Clopne PI AVR: HEX file for burning Atmega 8 and PCB Sprint layout.