For the last 5 years, I have been using a thermocouple probe to monitor my pipe temperatures. It has a nice little 4 or 5 inch touch screen and I can watch it remotely on my phone at home or at work. That is the fancy one, and parts for that cost around $80 or $100 now.
I wanted to see how cheap and simple I could go. It turns out $25 is about the best I could do without buying parts in bulk.
Thermocouple: $10
Nodemcu board (brain): $5.50
LCD display: $4.50
Thermocouple amplifier board: $5
Wires: some pennies
3D printed box: "free" - a friend printed it. He said it was pennies worth of material.
The LCD display I bought turned out to not be what I thought I was buying. I thought I would be able to draw graphics, but it is designed to display 2 rows of characters. I wanted 1 row of larger characters and it only allowed me to define 8 custom characters. By using a mix of custom characters and the display's built in character set, I was able to make a somewhat ugly numeric font that spans the two rows but is readable from a distance.
I might just replace that blue display with a red LED numeric display like the Auber uses. It would cost about the same.
![[Hearth.com] $25 Wood Stove Thermocouple Probe & Display](https://www.hearth.com/talk/attachments/20260124_072408-webp.345525/ "[Hearth.com] $25 Wood Stove Thermocouple Probe & Display")
![[Hearth.com] $25 Wood Stove Thermocouple Probe & Display](https://www.hearth.com/talk/attachments/20260124_072900-webp.345526/ "[Hearth.com] $25 Wood Stove Thermocouple Probe & Display")
It uses a $5 cheaper thermocouple amplifier so it is not as quick to respond as my fancy setup, but it is still light years ahead of a bimetallic coil style probe.
This one will not connect to a phone, but it does have wireless. What I can do is make one of these the "base" with the thermocouple taking readings, and then make multiple "remote" displays reading from the master and displaying the temperature in another room. Those would be about $10 in parts and would operate on their own mesh network separate from the home WiFi so there is no security risk, network setup, setting of DIP switches, or anything. Just plug it in. I prototyped that, but that was a while ago.
A mesh network means that they all talk to each other. So, If I have the base near the stove and want to have a remote display in the garage, but the garage is too far for reliable wireless communication, I can have a display in the kitchen as well that would act as a repeater to relay info between the garage and the base. A repeater with no display would be about $5 in parts.
To add a repeater or display, I would just have to plug it in and it would start talking. In the video, you can see a "heartbeat" in the lower right of the display. That is how I know the software is still running (not locked up, though it hasn't locked up yet). The same heartbeat would show on a remote display. The visible heart rate gives an indicator of how well it is communicating.
I think Auber needs to do something like that. I believe they offer a remote wireless display, but you might only be able to have one or two (it has been a while since I looked) and if you want to have a remote that is out of range you are out of luck.
When I started this little project, I was thinking about it like a product. What do I want that does not exist right now? But, to be clear I am not trying to sell a product with this post. I don't like the idea of the liability associated with wood stove monitoring.
The part that I wanted that did not already exist is the simple, no setup remote display and the option for adding a repeater. That might already exist on Auber's site now.
I wanted to see how cheap and simple I could go. It turns out $25 is about the best I could do without buying parts in bulk.
Thermocouple: $10
Nodemcu board (brain): $5.50
LCD display: $4.50
Thermocouple amplifier board: $5
Wires: some pennies
3D printed box: "free" - a friend printed it. He said it was pennies worth of material.
The LCD display I bought turned out to not be what I thought I was buying. I thought I would be able to draw graphics, but it is designed to display 2 rows of characters. I wanted 1 row of larger characters and it only allowed me to define 8 custom characters. By using a mix of custom characters and the display's built in character set, I was able to make a somewhat ugly numeric font that spans the two rows but is readable from a distance.
I might just replace that blue display with a red LED numeric display like the Auber uses. It would cost about the same.
It uses a $5 cheaper thermocouple amplifier so it is not as quick to respond as my fancy setup, but it is still light years ahead of a bimetallic coil style probe.
This one will not connect to a phone, but it does have wireless. What I can do is make one of these the "base" with the thermocouple taking readings, and then make multiple "remote" displays reading from the master and displaying the temperature in another room. Those would be about $10 in parts and would operate on their own mesh network separate from the home WiFi so there is no security risk, network setup, setting of DIP switches, or anything. Just plug it in. I prototyped that, but that was a while ago.
A mesh network means that they all talk to each other. So, If I have the base near the stove and want to have a remote display in the garage, but the garage is too far for reliable wireless communication, I can have a display in the kitchen as well that would act as a repeater to relay info between the garage and the base. A repeater with no display would be about $5 in parts.
To add a repeater or display, I would just have to plug it in and it would start talking. In the video, you can see a "heartbeat" in the lower right of the display. That is how I know the software is still running (not locked up, though it hasn't locked up yet). The same heartbeat would show on a remote display. The visible heart rate gives an indicator of how well it is communicating.
I think Auber needs to do something like that. I believe they offer a remote wireless display, but you might only be able to have one or two (it has been a while since I looked) and if you want to have a remote that is out of range you are out of luck.
When I started this little project, I was thinking about it like a product. What do I want that does not exist right now? But, to be clear I am not trying to sell a product with this post. I don't like the idea of the liability associated with wood stove monitoring.
The part that I wanted that did not already exist is the simple, no setup remote display and the option for adding a repeater. That might already exist on Auber's site now.
