.:madworm:.'s photos with the keyword: door alarm

The white push button switch triggers the staircase lights. I close the circuit with a small reed relay. As I couldn't make any sense of the wiring, I added a "rogue" wire from the doorbell switch. It provides 13.8V AC with enough current capability. The installation manual of this com system is quite terrible for people wanting to understand how it works. It only contains wiring examples for all the different setups you can choose from, but nothing substantial as to what the wires may do (which is power, which is signal...).

Initially I wanted to use a PDIP ATmega168, but it was just way too large. The knock sensor needs some more space, as it needs an opamp. Luckily the latest LED Ring boards already include a 5V regulator, which saves some more space. The number of available IO pins is sufficient as well (6 including RX/TX, but only RX is shared). I added a jumper to disconnect the reed relay from the RX pin when I need to update the code. It turns out that a load of 500Ω doesn't interfere at all. I can hear the relay click happily during upload.

Initially I wanted to use a PDIP ATmega168, but it was just way too large. The knock sensor needs some more space, as it needs an opamp. Luckily the latest LED Ring boards already include a 5V regulator, which saves some more space. The number of available IO pins is sufficient as well (6 including RX/TX, but only RX is shared). I added a jumper to disconnect the reed relay from the RX pin when I need to update the code. It turns out that a load of 500Ω doesn't interfere at all. I can hear the relay click happily during upload.

The capacitive sensing wire is just pushed into the lock's cylinder. Upon startup the device measures a baseline value.

The capacitive sensing wire is just pushed into the lock's cylinder. Upon startup the device measures a baseline value.

The white push button switch triggers the staircase lights. I close the circuit with a small reed relay. As I couldn't make any sense of the wiring, I added a "rogue" wire from the doorbell switch. It provides 13.8V AC with enough current capability. The installation manual of this com system is quite terrible for people wanting to understand how it works. It only contains wiring examples for all the different setups you can choose from, but nothing substantial as to what the wires may do (which is power, which is signal...).