Arduino 12V Car-alarm with PIR sensor and remote control - expertise needed. :-) Answered
This is my first "big" Arduino project and my first fritzing, so please bear with me. :-)
- Build the cheapest possible car alarm system with a loud siren
- It should be possible to activate/deactivate the alarm with a remote control.
- The alarm will once activated, sense any motion in the car (if someone breaks a window and tries to steal anything) and set of the alarm.
- The system should not drain the car battery so it should draw a minimum of power.
I've managed to build the first few things, but some vital steps are still needed and I hope you can help me sort these out.
Components used so far:
Arduino Pro Mini
- TIP122 transistor
- 2.2KOhm resistor
- 1N4002 diode
- Mini piezo siren (I used a 107dB siren with an operating voltage of 6-15Vdc and current consumption of 140mA)
- Lots of wires
I'm currently waiting for my PIR sensor to arrive together with the RF receiver/transmitter module, so for now I've added a basic switch to act as the PIR sensor and another for the RF module (activate/deactivate).
The components I'm waiting for are:
- An RF module that I need to order once i find the right one.
Questions that still remain and that I hope you can help me with:
1. The arduino should be powered by the cars 12V battery, however I've read that the car battery must be regulated as it delivers anywhere from 12 - 16V. I could connect it directly to RAW but in case the battery peaks above 16V i risk damaging the Arduino. I'm very unsure as to how I do this regulating best? One option could be to buy a "DC-DC step down converter - 4-35Vdc > 1,23-30Vdc" and set it to 5V, but maybe a more simple and/or cheaper solution exists?
2. Since the power consumption should be kept to a minimum, I plan to add the RF before the step down converter so the powering of the regulator (step down converter?) only happens if the alarm is activated from the remote. First question is: can I use a TIP120 for this and simply connect the RF to base, and the regulator to the collector? Second: In this case, the Arduino will be powered off the hard way by cutting power when deactivating the alarm from the remote - can the arduino take that in the long run? and finally, the RF receiver needs to get its power from somewhere, so what can I do here - is the best thing to use a 12V RF module instead of the Arduino 5V RF module or can this be solved some other way?
3. Any good ideas for minimizing power consumption?
4. Anything I can do to further improve the design? :-)
I'll update this post as I progress with the project including a more detailed step guide to how to implement this and the source code I'm using.
Instructables arduino posts and commets have helped me a lot during over the past few weeks working with Arduino so I hope you can help me reach the finish line with this project.