I have a tray full of old iMac temp sensors liberated during various SSD upgrades. I'm guessing these are using one of the one wire protocols but as I no longer have any working iMacs I can't reverse engineer them. Also, given that they're running about $5 online they seem a good source of cheep ambient temp sensors or even core temp sensors for pi uses.
Part number appears to be 820-1939a. Looks like two wires are power and the other two are data.
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jerunamuck
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- Joined: Tue Nov 25, 2014 1:59 pm
Re: iMac Hard Drive Temp Sensor Datasheet anyone?
Got any pictures?
The older ones used a TMP75, a 3V3-compatible I²C digital temperature sensor; datasheet - http://www.ti.com/lit/ds/symlink/tmp75.pdf
The older ones used a TMP75, a 3V3-compatible I²C digital temperature sensor; datasheet - http://www.ti.com/lit/ds/symlink/tmp75.pdf
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jerunamuck
- Posts: 3
- Joined: Tue Nov 25, 2014 1:59 pm
Re: iMac Hard Drive Temp Sensor Datasheet anyone?
Bingo!
Thanks for finding the datasheet! The print on mine has a dot of epoxy obscuring 'TM' on the IC label but all the other markings match exactly.
Here's a picture of the same sensor for the CD (APPLE, 820-1941-A)
On the HD sensor, R1700 has the resistor and R1701 is open. I'm guessing this is the addressing pins. Should be easy to work out the address with a DVM.
That makes the package pins VCC, SDC, SLA, GND from top to bottom. And according to this datasheet it's 5v tolerant so this would also work for Arduinos.
Thanks for finding the datasheet! The print on mine has a dot of epoxy obscuring 'TM' on the IC label but all the other markings match exactly.
Here's a picture of the same sensor for the CD (APPLE, 820-1941-A)
On the HD sensor, R1700 has the resistor and R1701 is open. I'm guessing this is the addressing pins. Should be easy to work out the address with a DVM.
That makes the package pins VCC, SDC, SLA, GND from top to bottom. And according to this datasheet it's 5v tolerant so this would also work for Arduinos.