AcuRite 5 in 1 temperature sensor replacement repair

[CapLeaker]

Got a new victim:

AcuRite 5 in 1 Iris outdoor weather station not updating the temperature / humidity anymore. The original sensor is a SHT21. Also there are identical other sensor manufacturers. I chose the HTU21D to replace the original SHT21. Both have identical specs. I've had two failure modes with these sensors.
A: outside temp stuck at -40? It's cold here at times in Canada, but not that cold!
B: stuck at some temperature and maybe updating once in 12 hrs or so.

Easy solution is to go to AcuRite website and purchase the sensor. Right? AcuRite SKU: 11197-VN1HSPCB. Well… they want USD$14.99 for the sensor plus USD$ 38.74 for shipping into Canada? Totalling USD$ 53.73??? Really?!?! By the time it gets here it costs me around CAD$78.00 All that for a little temperature replacement sensor? !@#$ not happening! You'd think they can put that thing in an envelope and mail it? Nope! So here is my antidote :

Went to AliExpress and bought an HTU21D sensor with the board for a buck fiddy each CAD$1.50! Comes with everything you need! Best thing is no modifications on the board are needed, besides swapping the cable out!

Depopulted the old original board and glued the new board to the old board with black RTV sealant (watch were the old sensor was). Then swapped the wires with the JST connector from the old board to the new board, put more RTV sealant AROUND the new sensor and called it good enough for Canada! The pictures explain the cabling pin outs.

Assembled everything, put the batteries in and? nothing updates on the main station?
Got a fix for that too. Take the battery cover off and slide the channel selector switch to a different channel and then back. Voila and you get the updated values of the outdoor unit! No reset required!

Here a few pix for you guys to follow my steps and enjoy cheap temperature / humidity sensor replacement boards!!! Cheers!

[stj]

by "chennel" i presume it has different I²C addresses?

[CapLeaker]

by "chennel" i presume it has different I²C addresses?

No. There are 3 RF channels you can select through a switch between the indoor and outdoor unit. All I did was taking the weather display unit, took the battery cover off and changed the channel selector to something else, then back again. The display outdoor side then updated and I didn't lose any history data.

As for the i2c temperature / humidity sensor: the replacement board has two pull up resistors on the clock and data line. I didn’t “enable” these by putting a solder blob in the middle, as the 5 in1 outdoor unit has them already installed on its main board.

[CapLeaker]

Why did in post #1 the attached PDF files disappear

[redwire]

Good you got it all fixed up. {attachment pdf's were OK when I looked days ago.}

What happens is one sensor goes bad and the entire weather station has to get tossed in the garbage because the manufacturer no longer sells that sensor.

Example is my Oregon Scientific temperature/humidity transmitter died and it's worked great even at -40°C (with a lithium AA battery) for over 10 years then it just went dead. I think the COB IC failed or maybe it didn't like years of a 1.7V battery.
I tried to buy a new transmitter and the company (Oregon Scientific) has been sold off to some chinese consortium that has mismanaged the products to death, they are no longer available. So sad. I could make an Arduino-compatible one but not battery+low power like the original.

Next try is the La Crosse garbage for sale everywhere, like Canadian Tire and Walmart etc.
I tried it was up to 10°C out so a warranty claim and they sent me a new sensor/transmitter but inside I found an older PCB. Same junk, inaccurate. I find La Crosse has bad firmware, needs longer delay time for the RC ADC circuit.

So I gave up and made my own ESP32/DS18B20 system, it needs mains power but works fine.

[CapLeaker]

Good you got it all fixed up. {attachment pdf's were OK when I looked days ago.}

What happens is one sensor goes bad and the entire weather station has to get tossed in the garbage because the manufacturer no longer sells that sensor.

Example is my Oregon Scientific temperature/humidity transmitter died and it's worked great even at -40°C (with a lithium AA battery) for over 10 years then it just went dead. I think the COB IC failed or maybe it didn't like years of a 1.7V battery.
I tried to buy a new transmitter and the company (Oregon Scientific) has been sold off to some chinese consortium that has mismanaged the products to death, they are no longer available. So sad. I could make an Arduino-compatible one but not battery+low power like the original.

Next try is the La Crosse garbage for sale everywhere, like Canadian Tire and Walmart etc.
I tried it was up to 10°C out so a warranty claim and they sent me a new sensor/transmitter but inside I found an older PCB. Same junk, inaccurate. I find La Crosse has bad firmware, needs longer delay time for the RC ADC circuit.

So I gave up and made my own ESP32/DS18B20 system, it needs mains power but works fine.

Same here. Had Oregon Scientific like 20 something years ago. Spare parts were scares, so I got the Crappy Tire La Crosse. Surprisingly after 10 years it is still working, but the temperature is like 4C too high. 5 years ago I got that AcuRite Iris. Works great, but it eats the temperature, humidity sensor. I guess I am close to the Atlantic ocean and the salty air doesn't help it very much! At least I've got plenty spares for a buck fiddy each and all is well again.

Another thing worth mentioning: I am still running the same batteries (4 x AA Energizer Lithium) for 4.5 years in that 5 in 1 outdoor unit and they still going strong! Measured 1.58V each a few days ago! That's pretty decent run time!

I have no idea what happened to the PDF’s for the two sensors. They disappeared from one day to the next.