ATC_MiThermometer
ATC_MiThermometer copied to clipboard
atc1441
negative temperatures
Dear Aaron,
This is a great hack - congratulations :-)
Can you please make the thermometer to work on negative temperatures too?
Also displaying the "-" sign somehow, and also transmitting the temperature at least in custom advertising mode.
Thank you, Gabor
wow, good to hear.
if you have a little time, may I ask You, to do a test with the device to put in the fridge in a bag, to see if it actually works in -10 deg Celsius?
Thank you a lot...
Hello,
I reviewed the code, and I see, it can display -9.9 degree indeed. It could display also any negative degree by not displaying the fraction: -9.9C -10C And it could signal the overflow somehow too. In case of over/underflow the code in show_big_number() just returns, what keeps the last data on the display, and it's not correct.
As my past experience, a few of my thermal sensor damaged after long time (10 years), what causes this overflow.
What is the termal sensor IC in this device?
The sensor is an SHTV3 but the SHTC3 is very similar and an datasheet is available for that.
You are right it is kind of a bug that the displayfunction just returns, a better function including lower temps is definitly possible
The degree can be lower thak -9.9 it will be correctly shown in the advertising data
Hi guys, are you saying it would be fine to use this outdoors then and it should show temps lower than -9.9C via the app?
I can not say for the stock firmware and MiHome app but the custom firmware does allow negative temps above -9.9°C And it was no problem so far to use the Thermometer outside or in the fridge at -20°C
Hello again !
By the way, when temperatures are negative, the broadcasted value is for example fff8. Shall I assume ffff is -0°C and fff8 is -0,7°C ?
Thank you :)
