Here is what I want to do: Control a 12 volt DC motor driven siren with an arduino uno.
Here is why: when I feed cattle I use the siren. the siren is used to call cattle to feed and will be used later to gather cattle.
Requirements:
-The siren needs to come on for 5 seconds then off for 15 seconds
-The siren needs to be controlled via a button or toggle switch
-Both siren and arduino must be powered by 12vdc power from tractor
-Here is what I know about siren motor:
-DC 96 W (I don’t know what that means)
-motor draws 8-25 amps
-starting amps require 25-28 amps
-duty cycle is 10 minutes
-14-12 gauge wire is recommended as is 30 amp fuse
Some of my main questions are:
-How to power the arduino with 12 vdc power?
-How to power the motor with arduino (use a relay, mosfet, other?)
Two weeks ago I purchased a sparkfun inventors kit to begin learning about electronics and arduino (because I see a multitude of applications of the arduino in the ranching environment).
I breadboarded a circuit with a mosfet, but the motor in the siren began smoking…probably not good. (maybe because I used a 15 amp power supply (ac to dc) to prototype my project?)
Where do I start? Any suggestions or comments would be much appreciated!
Not really know why the motor would smoke… It should have fried the electronics before the motor…
(maybe because I used a 15 amp power supply (ac to dc)
You need to read up on the difference between voltage and current. You can push voltage and pull current. A 15A supply does mean that it’s pushing 15A. The motor will only pull the current it needs.
You can power the Arduino with 12V. It has a voltage regulator. Might want to read up on Arduinos as well. You would need to use a FET, relay to control the horn due to it’s power requirements. You need to find a FET/relay that can handle that. If it was me, I would use a relay.
Since you’re asking these questions, I must ask how you had it wired up from the start?
What was the output voltage of the power supply? 12V? If your motor needs 25-28A to start and the supply can only give it 15A, then the PS voltage probably dropped really low. It’s possible that the motor started smoking because there wasn’t enough voltage to spin it up and thus cause it to consume less current. As a result, it was using too much current for too long and overheated. Does the siren still work?
You can eventually get this to work, I’m sure. However the power from a tractor magneto/alternator is going to be noisy as hell. You are probably going to need a lot of filtering before the Arduino can survive that environment.
If the motor is rated at 96 Watts, then at 12V it’ll draw 8 amps once spun up. I’d worry that your 5 secs of on time isn’t long enough to get it spun up.