A Raspberry Pi, one thermocouple, and a phone that tells me whether the stall is the meat or the fire.
It's two in the morning. The smoker has been going since lunch. The one thing I am not going to do is lift the lid to "just check." Every time you do that you dump the heat and buy yourself an hour you didn't plan on. CyberPit is how I know the temperature without opening anything.
CyberPit sits beside the smoker on a Raspberry Pi Zero. A single probe is in the meat. The Pi reads it, draws the cook, estimates when I'll hit the number I set, and taps my phone if something is wrong. I watch it from the couch, on a page I can keep on the home screen. If I'm holding a radio instead of a phone, I can ask Bud how the pit is doing. Of course I can.
It is on only when there is meat on the fire. The rest of the time the little computer is powered off. If a status check says the pit is unreachable, that is not an outage. That is a Tuesday with no brisket.
A thermocouple is two different metals joined at the tip. Heat makes a tiny voltage, and a small board turns that voltage into a temperature. The famous "stall" on a long cook is the stretch, usually somewhere in the 140s to the 170s, where moisture evaporating off the meat holds the temperature flat for hours. It feels like the fire died. A lot of the time the fire is fine and the right move is to wrap. Telling those two apart is the whole job.
Nothing here is exotic. A K-type probe, a MAX6675 board to read it, and a Pi Zero 2W small enough to live out by the pit. While a cook is running it samples about every three seconds and writes the numbers down whether or not I have a browser open. The graph on my phone is just a window onto that log.
When I pull the probe out to wrap, I hit pause first. Otherwise those minutes of room air look exactly like the smoker falling over, and the phone starts yelling about a fire that is fine. Pause leaves a gap in the graph on purpose. I can also drop marks on the cook as I go: wrapped, spritzed, sauced, flipped, refueled. Later I can drag across the chart and see whether the wrap actually changed the rate, instead of trusting whatever I remember at midnight.
Each cook keeps its own notes. What the meat was, how heavy, how thick, what wood, and a rating after the fact. I can export the run. The raw log stays even if I delete the write-up. Units are Fahrenheit in this house. The page will speak Celsius if a cook is set that way.
Three things are worth a notification. Everything else can wait until I look.
I set the number. When the probe crosses it, the phone gets one alert, not a stream of them. Drop well back under the target and it arms again.
If the meat sits between 140 and 175 and barely climbs for the better part of twenty minutes, CyberPit calls it a stall and asks if it's time to wrap.
A real drop is different. Falling hard, about five degrees off the recent high, is the loud one. That alert means go look at the fire.
The cook is saved as it happens. I can open an old one months later, mark a stretch of the graph, and see the slope before the wrap and after it.
The first few minutes after I start, or after I resume from a wrap, are ignored. The probe is still settling, and I don't want a false alarm for the act of sticking it back in. After that, the rate is smoothed so one noisy reading doesn't look like a crisis.
A stall is the meat doing physics. A flameout is the pit running out of fire. They can look the same if all you have is one glance at a thermometer. CyberPit has the last twenty minutes, which is enough to tell them apart, and it will bother me for the second one.
A serious cook wants two temperatures: the meat, and the air in the chamber. I want that too. There is a second build, two sensors and a proper converter, meat on one and chamber on the other. I do not cook on it. The last time I tried to bring that board up, it knocked the Pi off the network. The thermocouple path has already been through real brisket. That is the one plugged in.
So the page you would see during a cook is one big number, a target, a graph, and the marks I left myself. Chamber temperature is still a guess I make with the other thermometer, the old way. When the two-sensor version stops panicking the board, it can take over. Until then it waits.
Store probes are fine until the cook is fourteen hours long and the vendor's cloud, or their app, or their account, is having a night. CyberPit doesn't phone home to anyone. The numbers stay on the Pi. My phone is just another screen on the house network, and the alert is a push, not a subscription. If the internet to the outside world blips, the log is still being written next to the smoker.
That's the same reason the rest of the station is built the way it is. I would rather own the thermometer than rent it. The lid stays shut. The phone tells me if I actually need to walk out there.