Metal detector -2-

 After building the metal detector kit from the first blog post i received another DIY kit from Aliexpress for a metal detector. From this version i ordered (and received) two. Until now i only assembled one) . I did not (yet) find the circuit used in this version however as it contains other parts as than the first kit the circuit must be different.

The kit contains more transistors than needed so after building an testing i now have some extra transistors. An instruction manual or schematic was not included. Information which components to place where was on the PCB

I included a photo of the front and back of the PCB.

After assembling i powered the metal detector using 3 1.5 AA batteries (= 4.5V). This metal detector seems to work better than the one in my Metal detector -1- blog post. This second metal detector only has a buzzer. not an led. See picture below. It only gives a signal when metal is near the PCB. (It is possible to create a (false) signal by moving the batteries and battery wires near the detection coil. The pot meter can be used to adjust the sensitivity.

I have found a circuit for a metal detector using a 555 timer and i have some of these 555 times i stock.
Perhaps, some time, i also build a metal detector using the 555. However i  am also working on other projects and received some PCBs and other components for these project. And for now i have a nice working metal detector so i want to give priority for these other projects. 

Metal detector -1-

Recently i did buy this cheap DIY metal detector kit at Aliexpress.

Here some pictures of the parts ant the assembly. Soldering the components was not very difficult. As i wanted to use the power screw terminals in another project i soldered two Dupont pins instead for the power. In fact is was a three pin male Dupont pin where i removed the middle pin. The two outer pins where at exact the right distance on the PCB.

Below the circuit diagram for this metal detector found on the internet 

( https://www.epanorama.net/blog/2018/02/27/metal-detector-kit-converted-to-arduino-sensor/ )

I did build and tested the device powering it with 3 1.5 volt batteries (=4.5V) on the Dupont pins. My device continuous gives a signal that changes a when near metal. Changing the pot meter gives a change in the sensibility.This metal detector continuous gives a sound. Don't know if this is due to an error or intentionally. I did not do much troubleshooting to see if it was due to an error made during building and if i could improve it as i don't like it.

This is part -1- of my post about a metal detectors as i also ordered another cheap metal detector and i want to compare them.