Piezo upgrade

Hi everyone.
I didn't wait more that 48 hours after receiving my Bangle.js to upgrade it with a piezo buzzer.

This come from a smoke detector that I found landing on the ground in the street near my work a certain time ago. I dismantled it to keep for future projects some components (even some SMD capacitors...) and a piezo buzzer.

Image 1
Image 2

Just soldered two thin wires on it, tested it with an Arduino UNO.
Image 3

And, finally, put in my Bangle.js.
Image 4

Biggest thanks to Gordon that showed how to disassemble/re-assemble
the Bangle.js and the way to add a piezo buzzer.

Francis

Wed 2020.04.08

Were you aware that images are not rendering?

See 'Formatting Help' link adjacent to 'Cancel' button at the bottom of each edit window.

Hi Robin
Problem with images: upload doesn't seems to work and the google link (that works) is not rendered. Don't know why... (it works on other forums).
Francis

'and the google link (that works)'

Is it possible that it is necessary to log in at that destination, e.g. works for you as you are logged into that account?

'upload doesn't seems to work'

What exactly is meant by 'doesn't seem'?

Uploading will keep appending to end of the post, just can't insert. Click 'Edit' button on post #1 or post #3, click the uplaod a file link. Can only add one at a time up to a max total of five. Just did a .jpg

That's great! Thanks for showing your progress!

I just modified the post to include links rather than direct images (as that's what the URL was for) so at least others can see now :)

Hi Gordon and thank you for the modifications.
@Robin: when I use "Upload a file" that navigates on my computer, I choose a image but after... nothing happens. I'm not able to upload images using this way because it doesn't work (and it's not a problem of size or something else). So I posted shared links (no authentication required) but the image is not rendered.
So... I think that Gordon's is right to replace the images by their URL.
Francis

Coming from a smoke detector your watch must be ear-ringingly loud now! ^^

Honestly, whats the audible result? Is it clearly better than the vibration buzzer?

Hi Raik
Yes, it sounds better than the only vibration, but not too loud.
I took a small video with the Pomodoro timer app (because Alarms app don't use -yet- the piezo but the vibrator) with the vibration set to 'off' in the Settings.
You find this here.
Francis

Nice, what specs has that piezo?

...did I read Pizza upgrade? ...topping specs? ...sorry for the not so foreign joke in this foreign time we all go thru right now. It needs some humor to brighten things up.

On a more - or in other ways - serious note: the piezo is so quiet / low volume because it if 'free' between 'soft' things. if there would be a way to make it work like a piezo microphone (or probably your smoke detector), the element would have to be on 'solid ground' and the center would have to have a 'Stimmstock / tuning stick' like in the Violin that passes the vibration from the 'Steg / bridge' on the top onto the bottom - the membrane / speaker cone. The other thing that could work is a transducer 'bolted solidly' to the case, top glass is better than bottom metal.

The mic I had as a tinkering boy: looked like a small round pill box with a 7 hole in the top giving view onto a metal membrane wit a funny metal thing poking thru its center, fixated with a tiny bit of glue. Behind the membrane was a flat 1x1cm thin crystal waver of which three corners were solidly mounted in the box and the fourth corner had the other end of the funny metal thing fixated to the membrane. Incoming sound waves flex the crystal which creates electrons being pushed around its grid... and this is detected by wires connected to the sides which were silver coated...

Could not find a pic of such a mic nor find it... but I found - ironically this: https://www.instructables.com/id/Make-a-Guitar-Pickup-From-an-Old-Watch/

No need to explain 'ironic'... and it also makes me think if this could be used to make Bangle.js a recording device! ...hahaha...

Hi everyone !
@Mabe: thank you; this piezo was a part from a smoke detector and I don't know its specifications but only its size (27mm) that is a bit too large as you can see in this picture.
You have another post (see page 3, post #62 and after) that turns around piezo buzzers. You will get certainly an answer from there.
@allObjects: the better place for a piezo buzzer (and specially mine) is in a Bangle.js, not a guitar... ;-).
Francis

I got some EPZ-15MS60W from Reichelt and some for China, will try them in the next days.
Oh, you got this one too, just checked the other post #71.

Hi everyone
@MaBe: yes, you are right, my used piezo buzzer looks like the EPZ-27MS44W, with a same size and and same looking.
Francis

I just ripped some of these out of some old Tile keyrings!

Unsuccessfully soldered one so far 🙈it seems there's a coating on top that doesn't like being soldered onto (I used liquid flux, but the connection was still mechanically weak and easily breaks off of the thin coating).

EDIT:

I managed to solder to the + terminal of the Piezo after watching a video that shows you can in fact scratch the coating with a razor blade - it's still a very brittle connection, but I managed to solder to the correct pins to test it out and got beeps!

It was definitely louder, but there's no way i can solder the connections into the watch without something breaking (i already tried twice!)

It was a fail, but I learned some stuff too, so it's ok!

Hi everyone
@Stoaty: well done, I hope it will last and you will enjoy the sound on your Bangle.js !
Francis

I got a bunch of 20mm piezo discs off Amazon, removed the casing from one with a pair of pliers, and soldered it into the watch as per the video - works fine.

Hi everyone
@skm Cool ! Good job as your piezo is smaller than mine (27mm) !
You can enjoy the sound of the Bangle.js from now.
Francis

This is Just the kind of thing I wanted to do! Thanks @Fram !
Any advice for someone trying to do this now?
I am not the best sold-er in the world so I wondered how hard it is to do this? don't want to mess up my watch :-P

I need to do a video on this, but I actually just got around to trying some different things with Piezos and the results are a bit disappointing.

However it seems that if you don't care about the heart rate sensor, you could poke out the little circle in the middle and glue the piezo over that, and it might actually be ok.

Soldering shouldn't be too bad as the pads are quite far away from other components, but you'll still need a proper soldering iron (not a gas powered one, or a massive one you use for stained glass :)

Hi everyone !
@Gordon and @DrBard : my soldering iron is low power Antex (CS18 / 18W) with a thin tip (0.5mm).
If you can do a video for this upgrade, thank you because, unfortunately, I dind't took the time to do so.
Francis

Well, I will see what I can do @Fram, Not that good with doing videos but we will see.
Would you recommend any particular Piezos @Gordon? I am not looking for anything that load. Honesty I use my watch as an alarm to wake me up but not my partner, so just improving it a little bit would be good for me :-)

I don't have anything right now that I'd feel confident recommending. None of the stuff I tried was great, but I did find some cool tiny ones like https://uk.farnell.com/multicomp/mcabt-456-rc/audio-element-piezo-9-5khz-12mm/dp/2433032 if you wanted to try sticking them to the rear of the watch