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https://github.com/dustin/icebox

Tool for managing multiple AcuRite 986 thermometers
https://github.com/dustin/icebox

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Tool for managing multiple AcuRite 986 thermometers

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# icebox



I've been trying to measure my refrigerator and freezer temperatures

since a power outage a couple of months ago.  My zigbee idea worked

for around a day, then failed me miserably for reasons I don't fully

understand (other than the stack being somewhat unreliable).



I later learned about [AcuRite 986](https://www.amazon.com/dp/B004QJVU78)

kitchen thermometers that operate in the ISM band to populate a little

screen they come with.  [RTL 433](https://github.com/merbanan/rtl_433)

can pick this stuff up with cheap SDRs you probably have lying around,

so I grabbed a couple sets and tried it out.



One problem I (and apparently other people) ran into is that you can't

distinguish more than two units.  They're sold as a kit for your

kitchen and they assume everyone only has a refrigerator and a

freezer, so that's all you get.  The protocol communicates one of

two possible channel values and a semi-stable unit identifier (seems

to reset when you change batteries and possibly other times).



I also found that my radio picked up four plausible units that, if

they actually exist, are not mine.  (I live far away from anyone else

who'd be using these, but the problem might exist anyway).



So I built a little tool that will watch the MQTT data RTL_433 emits

and try to figure out which sensor is being reported and name it and

retransmit that name elsewhere.



## Prerequisites



First, get `rtl_433` doing the thing:



```sh

rtl_433 -F "mqtt://$mqttserver:1883,user=rtl433,retain=0,devices=tmp/rtl_433[/id]"

```



This causes messages to be delivered that look like this:



```

tmp/rtl_433/27397/time → 2020-11-06 19:03:40

tmp/rtl_433/27397/id → 27397

tmp/rtl_433/27397/channel → 1R

tmp/rtl_433/27397/battery_ok → 1

tmp/rtl_433/27397/temperature_F → 0

tmp/rtl_433/27397/status → 0

tmp/rtl_433/27397/mic → CRC

```



The fields are delivered as discrete messages, so I have to do a bit

of accumulation before I can transmit anything, but they should all

happen around the same time, so it's fine.



## Usage



Now that you've got data coming in, let's send it back out using this

tool:



```

Usage: icebox --mqttURI TEXT --inPrefix TEXT --outPrefix TEXT --nameFile STRING



Available options:

  -h,--help                Show this help text

  --mqttURI TEXT           URI of mqtt server to talk to

  --inPrefix TEXT          Input prefix (e.g., rtl_433/)

  --outPrefix TEXT         Output prefix (e.g., sensors/)

  --nameFile STRING        Path for channel naming rules file

```



You'll need to provide values for all the parameters, but `nameFile`

is probably the least obvious.  It provides default naming rules for

messages as they come in.  A super simple example might look liek

this:



```

channel 1 -> fridge

channel 2 -> freezer

```



That's enough to get you up and running with a pair of sensors.  But I

have three, two of which are on channel 1.  But I can tell them apart

by temperature, so before I just declare channel 1 fridge, I see if

it's too cold to be the fridge:



    channel = 1 && temperature < -5 -> deepfreeze



This line (above the other channel 1 definition) lets me tell my three

apart.  So starting with those rules, an invocation like this:



```

icebox --mqttURI mqtt://$mqttserver/ --inPrefix tmp/rtl_433/ --outPrefix sensors/ --nameFile name.conf

```



will get you results that look like this:



```

oro/rtl/freezer/temperature → -18.88888888888889

  MessageExpiryInterval 900

oro/rtl/freezer/battery_ok → 1

  MessageExpiryInterval 900

```



(i.e., the temperature and battery reading with a 15 minute

expiration)



This should also reject new devices coming in matching your current

rules, so my graphs will stop having weird spikes from rogue

readings.