Making bGeigie buzzer louder?

[Alberto Villa]

Hi,

My bGeigie sends out very weak clicks from the buzzer. I can imagine two causes, supposing that the buzzer is OK:

a) Extremely short-duration pulses coming from the iRover detector board,

and/or:

b) Very low current due to the 10 kOhm resistor R10 in series with the buzzer (see enclosed schematic).

Has anybody succeeded in getting a louder sound, for instance by reducing resistor R10?

Thank you and regards!

Alberto

[Sean Bonner, Safecast]

It’s designed to be quiet on purpose, so that you can only hear it when it’s out of the case in survey mode so that it’s not annoying and doesn’t draw attention when logging in normal situations.

-s

Sean Bonner

Co-Founder, Director of Global Operations

Safecast.org | pgp key

[Pieter Franken]

As Sean mentioned I designed the circuit such that it only becomes audible when you're measuring something hot and you can use the sound to "zoom in" on the exact location of the hotspot.  At lower levels it's supposed to be more soothing. By driving it from the iRover it also reduced the number of components. Lowering the restore will not do much to the volume and may cause a problem when you are measuring high levels as the network that hangs off the iRover is designed to stay within the current limit of the iRover over the full range (and thus properly get counts) You can replace the buzzer with a buzzer that click's louder, or add a little circuit to create a more audible click. You may notice theres a few solder pads next to the buzzer and those can be used to bring the audio signal out to a headphone or amp.

Pieter

[Alberto Villa]

Thank you very much, Sean & Pieter.

And compliments for the overall design. Simple and effective.

Regards,

Alberto

[Dan Bobczynski]

Do you know of a small amplifier board I could use to easily drive a 1 or 2 watt speaker to amplify the sound?  It turns out that for some usage cases, sound is the best way to monitor the Bgeigie when we can't constantly look at it.

Dan

[Pieter Franken]

Hi Dan,

I have been able to get a bit more sound with a larger piezo, but not too much. 

The way I designed it is not allowing the piezo to get more sound as it basically is fed by a 60uS one time pulse from the iRover. (This was done to keep the circuit super simple and not use the Arduino for driving the speaker or driving people crazy :-)

Best is if you build a small circuit that is trigger by the pulse and then puts out a short pulse burst in audible frequency (e.g. 1khz) This will create a much more audible output, even from the small piezo on the board. A NE555 would probably do the job.

Also note that the PCB has an unused connector “audio out” this allows for connecting to an iPhone for pulse counting using a TRSS board from spark fun. It should be possible to use this connector to build a small pulse/amp circuit to drive the piezo. 

Best,

Pieter

---
Pieter Franken

+81-80-3351-4519 | pieter....@gmail.com | linkedin