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dmlandrum

Soldering leads to a piezo disc + query on bender size
« on: December 17, 2009, 10:37:57 AM »
A lot of my sonic experiments involve the humble piezo bender disc. The problem is, getting them with leads soldered from Radio Shack costs more than the benders alone in bulk, there's not much choice in size and resonant frequency, and cracking them out of that plastic package they come in can damage the disc inside (I've ruined two that way, at $2 a pop). Piezo benders can be had for super cheap in bulk from Mouser, Newark, and a bunch if other places, but they come with no leads attached. So my question is, does anyone know how to solder leads to piezo discs without damaging them?

Thank you for the help.
« Last Edit: December 17, 2009, 07:01:09 PM by Consul »
Darren Landrum

Be comforted that in the face of all aridity and disillusionment
And despite the changing fortunes of time,
There is always a big future in computer maintenance.


haima

Re: Soldering leads to a piezo disc
« Reply #1 on: December 17, 2009, 12:06:50 PM »
perhaps cleaning the area you wish to solder to with steel wool? that is if corrosion is making it hard for the solder to flow...

other than that, i dunno - set your iron a little hotter than normal? but try to be quick, they might not like to be overheated for to long.

jdbakker

Re: Soldering leads to a piezo disc
« Reply #2 on: December 17, 2009, 12:25:01 PM »
Forum member leswatts recommends using a hot plate and not too much heat.

JDB.
[Les has more useful/interesting things to say about piezo transducers; wouldn't hurt going over a few of his old posts]

KKLL

Re: Soldering leads to a piezo disc
« Reply #3 on: December 17, 2009, 01:24:17 PM »
I've done this a couple of ways...One is to use very thin solder like 28 guage and a low heat soldering iron with a fine tip.  Tin the leads of the cable then clamp the connections in place with forceps or hemostat clamps and dab the iron tip on the leads very quickly.  You might want to practice this technique on a ruined piezo disk.

The other way is to attach the leads using conductive epoxy.  This takes a lot longer because of the time it takes the epoxy to set, but results in a good electrical connection.  I place a small piece of wax paper over the leads as I clamp them down.

You can also buy "unshelled" piezo disks with leads at various supply houses like Mouser or Digi-Key.  I unsolder the leads very quickly and use shielded lavalier mic cable.  Check out Digi-Key part 102-1126-ND.  If you don't want to unsolder the leads, you splice your cable to the leads and twist the red/black leads to get some shielding to reduce noise.

The main thing is to work quickly with the least amount of heat so you don't fry the piezo coating on the bender. 

dmlandrum

Re: Soldering leads to a piezo disc
« Reply #4 on: December 17, 2009, 01:57:00 PM »
I hadn't seen uncased benders with leads attached, but if they're available, heck, that's half the battle right there. :) Thanks for the tips.
Darren Landrum

Be comforted that in the face of all aridity and disillusionment
And despite the changing fortunes of time,
There is always a big future in computer maintenance.

dmlandrum

Re: Soldering leads to a piezo disc + query on bender size New
« Reply #5 on: December 17, 2009, 07:05:54 PM »
Hopefully, Les will see this. :D

I finally found some various benders on Digikey with leads attached, and there are a variety of sizes. Les mentioned in another thread that the higher-frequency ones are better for contact mic pruposes, so I zeroed in on this particular beauty:

http://parts.digikey.com/1/parts/15-buzzer-piezo-element-6-5khz-20mm-ceb-20d64.html

20mm, 6.5khz resonant frequency. With leads. That's important.

However, I seem to recall reading elsewhere that the larger, lower frequency ones are best for contact mics, if you're going through impedance conversion. I'm just trying to clear up this issue. Thank you!

Also, one of my areas of interest is making a DIY hydrophone or two: http://sonar-fs.lboro.ac.uk/uag/downloads/bender2.pdf -- Just curious if the same rules would apply. Thanks!
« Last Edit: December 17, 2009, 07:19:01 PM by Consul »
Darren Landrum

Be comforted that in the face of all aridity and disillusionment
And despite the changing fortunes of time,
There is always a big future in computer maintenance.


 

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