attiny - which EXTERNAL temperature sensor?

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vex_zg
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attiny - which EXTERNAL temperature sensor?

i’d like to get temperature reading from the host body or under the pill.

Any recommendations?

I actually found a candidate a few months back but I lost & forgot it

I’m using attiny85, but I don’t want to use the internal temp sensor.

thanks

tterev3
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I’ve used generic 47k NTC thermistors successfully in quite a few applications. If you have a sleep mode, make sure you can turn off power to the voltage divider though

vex_zg
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tterev3 wrote:
I’ve used generic 47k NTC thermistors successfully in quite a few applications. If you have a sleep mode, make sure you can turn off power to the voltage divider though

thanks for the tip. I remember reading some benefit of a LM35 over a thermistor, but now that I googled it again it is mostly about the LM35 having a calibrated output vs. temperature. But since LM35 requires at least 4V I can’t use it anyway.

what about this thin film resistor?

http://www.ebay.com/itm/10pcs-New-NTC-Thin-Film-Thermistor-MF5B-SMD-100K-1-Stable-for-3D-Printer-S5-/161484332587?hash=item2599375e2b:g:SF0AAOSw2XFUZa49

tterev3
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vex_zg wrote:
what about this thin film resistor?

100k seems like it could be too high. You have to consider the input impedance of the ADC in the microcontroller and make sure your signal will be strong enough. Putting a small capacitor from signal to ground can help you measure a high impedance signal though

Microa
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I employ LM35 or LM45 for 2 cells buck driver. RMM recommends MCP9700 which VDD = 2.3 to 5.5V.