Core Electronics Forum

Fast vibration sensor without Arduno

Hi guys. I’m trying to connect a fast vibration sensor to an electronic doorbell powered by a 9v battery. I want the vibration sensor to act as the switch instead of a push button bell. The sensor will be attached to a ships bell, hence the vibration sensor. I have been advised I may need a relay. I prefer to not use an arduno board in this stance.

Thanks in advance

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The doorbell will dictate what you need. For instance, this item
Fast Vibration Sensor Switch (Easy to trigger) Australia (core-electronics.com.au)
will switch 20ma, which is enough for a typical logic circuit. If the doorbell switch is driving some sort of IC to generate the tone (for instance, if it’s a wireless doorbell and the switch is connected to some logic in a controller board) then 20ma will be adequate. If the doorbell switches power to a buzzer then it is likely it is switching more than 20ma and you will need a sensor that switches a higher current, or a driver of some type such as a relay.

You also need to consider what type of switching the doorbell can handle. A simple vibration sensor will likely trigger multiple times in rapid succession. A more complex arrangement will trigger once and then do nothing for a certain short period before it can trigger again. If the doorbell can’t cope with multiple rapid switches then you need to allow for that.

So the place to start is with the connection to the doorbell.

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Hi Jeff. Thanks for your informative response. I’ve attempted to attach a picture. The door bell is a wired electromagnetic doorbell.

I believe purchasing an appropriate relay maybe the best course of action at this stage.

I take note of the potential for the vibration switch to trigger multiple times and will need to compensate for this issue.

As you can probably tell I’m a complete novice but keen on expanding my (basic) knowledge for this project. I am also open to other suggestions in relation to attaching a buzzer/bell to my ship bell or if a more appropriate trigger is available.

Thanks

Darren

Would it not be simpler to tap off a couple of extra wires from the button input to the bell as your signal?

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I assume u mean so I can utilise the push button from the bell. The issue still remains creating / installing a switch that closes the circuits when the bell is rung. Ideally I do not want to use a push button switch at all.

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So what’s causing the bell to ring, if not the push button?

The clanger. Hence the issue connecting switch (vibration switch) to the electro magnetic unit.

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Ah, now it becomes clear. You want the electronic doorbell to ring when someone rings the non electronic bell! Sorry, I wasn’t understanding that.

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Hey Darren,

Any chance you could modify your bell to be conductive in the right places to trigger the bell that way?

That might be a little less fiddly.

A microcontroller would open up more options like sound/vibration sensing as well.

Keen to see how you go with this!
-James

Hi Darren,

As @Jeff105671 has covered the fast vibration sensors are only rated to 20mA and your doorbell seems to consist of a power supply, a solenoid, and a switch. The vibration sensor won’t be able to directly substitute for the switch as it doesn’t have the current rating, you will need either a sensor capable of more current or a relay for the vibration sensors to interface through.

You may not require a microcontroller but it will depend on how long your vibration sensor stays “on” after knock. The added complexity of a relay isn’t too bad, you could use the doorbells battery, and a current limiting resistor to protect the vibration sensor, then just wire the output side of the relay in place of the doorbell switch.

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Hi James/Trent thanks for your Replies.

Trent - can u recommend an appropriate relay for this project please.

Appreciate all the input fellas

Might be worth connecting your vibration sensor (with relay as required) up to a small microcontroller board. If it were me, I’d be connecting to an ESP8266 with Tasmota installed on it, but if be looking to maximise possible connectivity and hooking into my Openhab system. Anything you do to make the connection between the bells go via some standard protocol will pay off if you wish to add more features in the future, such as triggering a camera to let you see who’s there.

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Hi Darren,

Sorry for the delay I didn’t see your reply.

Can you confirm for me what powers your doorbell? I am assuming you chose the 9V battery option not the 12VAC power supply option on the sticker.

If you are using a 9V battery then you should be able to rig something up with the Fast Vibration sensor.
If you wire the fast vibration sensor in series with the input of this relay and a suitably large current limiting resistor. Then the relay will release when the bell is struck https://core-electronics.com.au/pololu-basic-spdt-relay-carrier-with-12vdc-relay-assembled.html

The output of the relay can then connect in place of your pushbutton switch on your doorbell.

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No probs

Doorbell is 9v. Great info. Just purchased those components (relay/resistor) and will put them together once they arrive.

I will update you when I have done this. Thanks for the info. Really appreciate it.

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