We go through a lot of ice - especially now that it’s well over 100° each day.
Recently, the ice cubes in the bin had started to clump together. I cobbled together a data logger, using an ESP-32 and a digital temperature sensor. The ESP-32 sent a stream of data to an old laptop, which I perched on top of the refrigerator. I took readings every 10 seconds, with the probe positioned above the ice maker, and snaking out the top of the freezer door. After a few days, I graphed the data, and found that the temperatures during the defrost cycle were going up to 70° or even 80° degrees. So, I bought a new defrost thermostat for $6 on Amazon and went to replace the old one. The hardest part is emptying everything out of the freezer into a cooler. After that, it’s four screws, and the panel over the coils comes off. When I pulled on the old thermostat to unclip it from the evaporator tube, it came apart in my hand. Which seemed like a good indication that it was bad. I cut the old one out, spliced in the new one, soldered the wires and insulated them with adhesive-lined heat-shrink tubing. Then, I put it all back together, and took another four days of data. The new thermostat has a trip point of 60°, which translated to around 40° at the temperature probe. And, the ice isn’t clumping anymore, so I guess I fixed it.
The total time to replace the thermostat was under 30 minutes.
I had all this lovely data (some 90,000 readings), so I played around with it in Plot2x, and Excel. The “after” average temperature was 3° cooler than the “before” temp, and the defrost highs were as much as 40° lower.
Totally nerdy and I love it!
LOL!
Having 90,000 data points is kind of a challenge - although Excel will graph it, it’s really hard to manipulate that much data. Plot2X is super-cool - it will allow you to pan and zoom in the graph without messing around with ranges - something Excel can’t do. But, the UI needs a lot of work.
Oh, and - we have ICE!
That’s cool (heh), was it all stuff you had on hand, or was the cost higher than $6?
Had to verify location before the 100F made sense. Haven’t gotten there yet, even had a rare rain today.
You’ve never been more attractive!
If the women don’t find you handsome, they should at least find you handy. – Red Green
My wife was fine when I fixed ours. Door insulator strip came loose and I thumb-pressed it back in the channel.
I’m an embedded controller designer. I’m working on a new system that uses the ESP-32, so I had a lot of different modules lying around. The temperature sensors were left over from another project (a device which helped prevent police dogs from getting cooked when their handlers forgot them in the car). The ESP-32 is supported by the Arduino development platform, and there is a lot of pre-existing libraries, so getting the code working only took a few minutes, Total cost, other than the replacement thermostat: $0.00
Bravo for helping police dogs! Could the same system be sold to parents to keep them from killing their kids in hot cars?
StG
There’s a lot of development going into “smart” car seats.
It’s conceptually not a very difficult problem, but I wouldn’t want to develop this without a huge, deep-pocket organization backing me. The legal liability is just way too scary - if something happens to a child when the system is in use, the lawsuits would ruin me.
So, sorry, no thanks…