Questions tagged [alarm]
The alarm tag has no usage guidance.
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Momentary push button switch to mute an alarm buzzer
I'm working on a circuit that needs to trigger an alarm buzzer (external dry contact trigger).
It should have a facility to mute the buzzer while the alarm is still on and turn it off when the ...
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Intercepting I/O on this simple vibration alarm / glass break alarm
I got these vibration alarms, but they're far too sensitive to leave as is.
I want to use HomeAssistant or something to get a notification and decide whether to trigger the alarm, and maybe do some ...
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How to design magnetic driveway alarm system?
I want to design "driveway alarm" which detects when a car passes by. I want to do the detection "magnetically" so it's easy to detect is a car and nto person or some animal. I was ...
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PIMA alarm system discharging but not recharging backup battery
We moved to a new place with an existing PIMA alarm system.
After changing the backup battery (which we thought was dead) we realized that the new battery worked only once during initial discharge.
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STM32F103C8T6 BluePill - HAL_RTC_AlarmAEventCallback - Not call
I have a problem: I can’t get the alarm clock to work on the BluePill board. I need to get an interrupt to wake up the chip from Stop mode. It seems to me that the problem is in my BluePill board, ...
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How would I use Double End Of Line resistors on stuff like relay, transistor, Piezo, Output devices so I could detect if the line was cut or shorted?
I'm trying to understand how you would go about detecting if the line was cut or shorted on an output to a device like a transistor, relay, piezo, etc, or other input devices like a Hall effect sensor....
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Best way to use Driveay alert output (Open Collector NPN)
I'm learning as I go on this project.
I have a beam-break driveway alert that I would like to get the output from on a device like an Arduino or Raspberry Pi and need some guidance on the best ...
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How does this old alarm system circuit work?
This is a pretty old alarm system based on an NPN phototransistor.
Why are there two transistors here, T1 and T2? Can we say that T1 is an emitter follower that amplifies the phototransistor current ...
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