Speaking Car Alarm, Users own words, with additional smoke alarm type sounder inside the vehicle, I have the market for it, happy to share revenue 60/40 with builder having 60%
I do not want to join any project (too much to do already) but any device will need bullet-proof power regulators and transient filters to keep the electrically-hostile environment at bay.
Almost any MCU will do the task (depending on how many sensor inputs you want) and a DFPlayer Mini can provide the audio content for little cost. The DFPlayer Mini takes a micro-SD card and has an in-built 3 watt audio amplifier which should be enough for most cars. It talks serial (9600) and so is quite easy to use.
The DFPlayer is best run using MP3 files starting with four numbers (0001xxx.mp3, 0002xxx.mp3 etc).
I recommend using separate LM317 regulators for the MCU and DFPlayer Mini (set the DFPlayer regulator to 4.2volts.) If driving the DFPlayer from a 5volt MCU, use a 1K ohm resistor in series with the Rx pin.
Alarms of differing sound level and input voltage are readily available.
I do not want to join any project (too much to do already) but any device will need bullet-proof power regulators and transient filters to keep the electrically-hostile environment at bay.
Almost any MCU will do the task (depending on how many sensor inputs you want) and a DFPlayer Mini can provide the audio content for little cost. The DFPlayer Mini takes a micro-SD card and has an in-built 3 watt audio amplifier which should be enough for most cars. It talks serial (9600) and so is quite easy to use.
The DFPlayer is best run using MP3 files starting with four numbers (0001xxx.mp3, 0002xxx.mp3 etc).
I recommend using separate LM317 regulators for the MCU and DFPlayer Mini (set the DFPlayer regulator to 4.2volts.) If driving the DFPlayer from a 5volt MCU, use a 1K ohm resistor in series with the Rx pin.
Alarms of differing sound level and input voltage are readily available.