The current electronics are not robust enough. In moving the components over to the new housing, things are coming apart, soldered connections are failing, etc. There’s not really enough space in the box so everything’s crammed in and nothing has any strain relief so the cramming-in is causing failures.
There are two options:
- Replace the current nest of wires with a custom-made shield.
- Replace the entire thing with a standalone Arduino – one board that includes all the supporting circuitry
Either way, I think I should also move away from the two relays currently used to control the bang and the siren and just use transistors instead – I’m not sure why I didn’t do that the first time.
The schematic I have is not actually right as the indicator light has a voltage doubler to bring it closer to the required 24V. I should make a new one.
No data sheet for the central locking actuator and nothing much came up on googling. Attempted to measure peak curtent with multimeter that has no peak function… the highest value I saw was about 2.5A, so let’s assume 3A@11.1V. This probably requires a MOSFET to switch.
Siren is 350mA@12V according to the datasheet.
- How to use a transistor as a switch – useful guide to the required calculations
- How to use a mosfet as a switch – ditto, as the actuator (probably) requires more than a transistor can safely switch
- Making a custom shield
- Data sheet for the siren
- Schematic for powering an arduino using an LM7805
- Perfboard arduino, also, building an arduino on a breadboard
- Using an Arduino as an ISP, also includes a minimal circuit – no crystal