I want to learn more by making a simple doorbell controller. I have an old fashioned bell that continues to ring as long as the button is pressed. I have an annoying friend who will come and hold it and continue to ring it until someone lets him in. So, I thought it would be cool to limit the ring duration, and prevent subsequent ringing for a few minutes. Further, I thought it would be cool to make a different type of ring pattern based on which button (front door or back door) is pressed.
First, I'd like to know the best way to use the power that should be available near the doorbell (I believe 24vac) to power the arduino. I have a couple of spare LM2596 step-downs but I guess they need dc input?
Any other tips from people who have done similar projects would be great!
Turn the AC to DC using a single diode and a large capicitor. Note you will get 1.414 times 24 V.
Then cut it down with a regulator to power the arduino.
Use an opto coupled triac to turn the bell on and off.
I guess I could use the LM2596 module to cut down the voltage, and i have a relay module -- could i use that to turn the bell on and off? What sort of diode and capacitor do i need to use?
my evil side would offer that you could have prolonged button holding charge a capacitor that, once some level is reached, would then discharge at the button.
using your idea as a press and then create an automatic delay is fine. however, I am in a rather foul mood tonight and would off a second evil option. after 2 second, a piezo anunciator be powered up at the location of the button.
my good side would offer that you could play some text like " the button has been pushed, the bell has sounded. hold on, I'll see if I can make more noise to get their attention." followed by a much louder speaker at the front of the house "HEY YOU UPSTAIRS, THERE IS SOMEONE AT THE DOOR"
in a friendly way, you could have the voice offer
"button has been pressed, signal has been sent, thank you"
then, "stage two alert, button failure is imminent,"
then " sprinkler system has been activated. hold button to open valve"
Back in the day I used a bridge rectifier from radio shack, a 7805 regulator chip, and a big capacitor. A diode between the rectifier output and the capacitor might improve things.