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Is my eTape faulty?
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Is my eTape faulty?

by jwinterton on Sun Jul 03, 2022 7:23 pm

Hi - I recently installed two 8" eTape sensors from Milone to measure nutrient levels in a hydroponics project. I noticed while calibrating that one is significantly out of spec.

It should be 1500Ω empty, 300Ω full, ± 10%. One sits nicely in this range but the other has an empty resistance of 1059Ω which is well outside the spec and overall its sensitivity seems poor and non-linear compared to the other. I have inspected it and can't see any obvious physical damage.

I really need it to be super accurate - I am hoping to replace an ultrasonic solution with an accuracy of +/- 2mm, so it needs to improve on that (and should from the spec).

Any thoughts appreciated,

Thanks.

jwinterton
 
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Re: Is my eTape faulty?

by adafruit_support_mike on Tue Jul 05, 2022 8:51 pm

Just to check, what resistance do you see across the reference pins 1 and 4?

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Re: Is my eTape faulty?

by jwinterton on Sun Jul 10, 2022 8:51 am

Hello Mike,
The reference resistance is 1388 ohms.
Regards,
John

jwinterton
 
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Re: Is my eTape faulty?

by adafruit_support_mike on Tue Jul 12, 2022 4:21 pm

Thank you.

That value is within spec, and is farther from the measured sensor value than from the nominal value. That supports the idea that something is off in the sensor.

Send a note containing a link to this page and your order number to support@adafruit.com. The folks there will get you a replacement.

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Re: Is my eTape faulty?

by jwinterton on Wed Jul 20, 2022 6:00 pm

Cheers Mike - thanks for confirming.

jwinterton
 
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Joined: Sun Jul 03, 2022 7:14 pm

Please be positive and constructive with your questions and comments.