Sometimes you need to know the temperature of something from a distance. It can be a smokehouse, a barbecue, or even a rabbit house. This project from might just be what you’re looking for.
Remotely control meat, but not chatter. It consists of a MAX31855 thermocouple amplifier designed for use with popular K-type thermocouples. It connects to a Texas Instruments CC1312 microcontroller that sends thermal measurements over the 802.15.4 protocol on which technologies such as Zigbee and Thread are based. It is able to send radio messages over long distances without consuming much power, which makes it possible to use a CR2023 coin cell battery in this project. Combined with firmware that puts the system to sleep when no measurements are being taken, expects the project to run for up to several years on a single battery.
Messages are collected and logged in Grafana settings, where they can be easily plotted. For added benefit, any temperature outside of the set range will trigger a smartphone alert via IFTTT.
Keeping a close eye on temperature is the key to cooking delicious meals with smokers, so this project should serve well. For those who want to remotely monitor their temperature with minimal hassle, this should work too!
In the worst case, the thermocouple itself would be used to charge the capacitor and power the transmitter …
As far as your thoughts go, my starting point could be reading a 1968 RCA research paper for NASA to see what should be used inside the RTG* (the power supply used in the 1977 Voyager space probe should have appeared here).
Keep in mind that if you want to use a thermocouple to measure something, for high accuracy** you ideally want no (or very little) current to flow.
However, if you want the junction to produce power, then you need to draw as much current as possible while optimizing the maximum power to be less than the maximum voltage (the voltage drop across the junction will be further reduced, and the drop across the connecting wire, since they have resistance, the more current you draw, and the resistance also changes with temperature – the higher the current, the higher the temperature).
I’m wondering if it’s possible to create a quick and dirty 2D meter where I measure current and voltage and measure temperature. Then the look-up table is only used for current and voltage measurements, not for generation mode, static mode, and temperature measurement mode.
By using our website and services, you expressly consent to the placement of our performance, functionality and advertising cookies.learn more