The project originally started in 2020 before I moved to Japan.

I bought a 4G LTE-Modem module and other things including a LiPo pack. I didn't look at the LiPo pack dimensions so it wouldn't fit inside, so I looked at the pack and it was 2 cells put together to get the 7000mAh. Like hackers do I very carefully cut the shrinkwrap knowing the dangers of shorting a LiPo and folded one of the cells over the other and taped it together. It would now fit.

I decided to start with one of the distictive features of the project, the bells. I searched around online and found the MC34063A which could be used too boost the voltage to 40 volts from the voltage from the LiPo pack. I ordered the parts and built it using a breadboard, it worked perfectly. 

Then of course you would need a H-Bridge to turn the DC into AC at the specified frequency that you want the striker to move at, 20hz for example. Found a design for that as well using P and N channel mosfets. I repurposed those from an old broken UPS. I programmed a pic to alternate the pins which controlled the mosfets through 2 transistors. The N-side mosfets got very hot I thought it was because the parts were old so I just put heatsinks on them. Probably due to insufficient gate voltage. The bells rang very loud.

When I transferred the PSU and H-bridge to perfboard the H-bridge broke. Think one of the N-channel mosfets gave up. Not sure If I had any deadtime at all.

Then I moved to Japan and the project got a bit derailed but I switched out the mosfets for others and at that time I didn't know about RDS(on) so the bells weren't as loud anymore but the mosfets at least didn't get hot. Then the project got put in a box until recently when I got some more time to work on it.