This topic contains 6 replies, has 4 voices, and was last updated by Antonio Russek 10 months, 3 weeks ago.
October 28, 2018 at 1:56 pm #6286
Will Cortado work well with a PVDF Film sensor instead the ceramic sensor?October 29, 2018 at 11:33 am #6300
I actually haven’t tried that, but theoretically it should work. One thing to be mindful of is that often time PVDF piezo sensors are is more sensitive than PTZ piezo sensors, depending on the application. So you may have to reduce the incoming voltage via a voltage divider to account for the possible higher voltage input to the Cortado.
Now that you’ve got me thinking, I’m going to get some film piezo sensors and do some experiments when I get the chance. Thanks for bring it up.
-BrachOctober 31, 2018 at 5:19 pm #6339
I have a bunch of MEAS brand model “LDT0-028K” PVDF piezo film strips that I have been experimenting with. I harvested them out of old products for testing on acoustic drums.
I can drop a few of them in the mail and get them out to you if you like to experiment with them and report back to us with the results. It’s only going to cost me the price of a stamp to get them out to you. They will be coming from Milwaukee, so you should get them the next day.
Here is the specs for the ones that I have:
If you want them I need the full postal address you would like the sent to. If they work well then others can get them off of http://www.sparkfun.com for dirt cheep.
– Æ.drumsNovember 1, 2018 at 9:22 am #6354
Wow! Certianally! Thank you very much for the offer.
Our address is:
Zeppelin Design Labs
2950 N. Western
I’ll play with them and see what I can figure out. I’m noticing the datasheet has some interesting information presented as experiments that the manufacturer has done. What devices do you harvest these things out of?
Thanks again!November 1, 2018 at 11:10 pm #6364
You got 5 of the LDT0-028K on the way to you via US-POST. The real only vulnerable attribute of these piezo film strips are when you solder them, it’s a good idea to use an alligator clip heatsink on the lead as you solder wire to the terminal so the plastic wont melt. The don’t brake like ceramic elements; they are really tuff.
I pulled these off of some old TV’s to get the VLCD panels; I striped them out as I was recovering the LCD screens. Here is a link to the specs of board they got pulled from:
They functioned as a vibration detection switch that would turn off the screen if motion was detected. I suspect this was an automotive safety thing to keep the driver from watching the screen when the vehicle was in motion.
Here is another link (on digikey) that shows more of the MEAS products including a shielded version of this piezo filmstrip:
I have been using 3 of the MEAS CM-01B on a 4-chanel deep memory scope to capture the data; the CM-01B Contact Microphone manual shows the charge circuit used to amplify the circuit; see link:
Before I got my hands on the CM-01B I was using the piezo filmstrips with my DIY logarithmic op-amp based charge circuit to isolate and amplify the signal. The common mode rejection circuit of the Cortado should perform really nicely with these PVDF strips.
The Cortado’s I just ordered will be getting hooked up to a very small portable ZOOM H6 digital recorder that has 4 phantom powered XLR jacks. It would be a huge vantage point having transducers that are elastic rather than ceramic for use on a portable setup that interacts with percussion based Instruments. Their is an obvious single output difference between how the PVDF film works and the ceramic crystal. Hopefully this will become a fun activity on your side when you explore the PVDF behavior.
– Æ.drumsNovember 2, 2018 at 1:50 pm #6376
Thank you so much!
I’m really looking forward to playing with these things. The links you provided are really getting me inspired to start designing some new things with piezo film. I’ll make sure to use a heat sink when soldering them. Thanks for the heads up. Please keep us posted with how these work in your application of drum mics with the Cortado. I fear they may have too much gain, but there are ways around that.
Thanks again and good luck!
-BrachNovember 2, 2018 at 2:43 pm #6377
Thanks Brad to be inspired about the PVDF sensors!
I have a CM-01B (used on electronic stethoscopes) plus
five MEAS sensors sitting on my desk, waiting for the right