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--- xnorit:public:summary:freezermonitoringsystem [2024/10/13 11:40] – timdv91
+++ xnorit:public:summary:freezermonitoringsystem [2024/10/13 15:31] (current) – [Freezer monitoring system] timdv91
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 ====== Freezer monitoring system ======
-{{ :xnorit:public:summary:frost:ksnip_20241013-133209.png?400|}}
+One of the first projects I did a couple years ago, was designing a custom freezer monitoring system. It's end purpose was monitoring -80°C freezer, but I tested them successfully in liquid nitrogen, down to -196°C.
-One of the first projects I did a couple years ago, was designing a custom freezer monitoring system. It's end purpose was monitoring -80°C freezer, but they where actually tested down to -196°C in liquid nitrogen.
+{{ :xnorit:public:summary:frost:ksnip_20241013-135153.png?400|}}
-The system communicates wirelessly with two gateways, by using a Zigbee mesh network between multiple nodes. Both gateways are operating 24/7, but the system does run perfectly fine on one gateway. The second gateway is purely redundant to reduce potential downtime.
+The system communicates wirelessly with two gateways, by using a Zigbee mesh network between multiple nodes. The system works perfectly fine on one gateway, meaning the second gateway is purely redundant to keep up-time as high as possible.
+Some of the collected live data is available at: [[https://grafana.xnorit.be/|https://grafana.xnorit.be/]]
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+===== PCB design =====
+{{ :xnorit:public:summary:frost:ksnip_20241013-134049.png?400|}}
+A custom PCB was developed using KiCad. The system is powered through a micro-USB connection, as these are easier to solder than USB-C connectors. I used an XBEE3 zigbee MMT module for communication, combined with two small CR2032 batteries as temporary backup in case of a power failure.
+A k-thermocouple is used for temperature sensing, which is connected to an MAX31855 thermocouple IC with integrated cold-junction compensation. Everything is read out by a custom programmed microcontroller, which sends all collected data to the XBEE3 over uart.
+Optionally it's also possible to connect the module to a freezers alert port, which is basically a relay that triggers whenever the Freezer itself detects an issue. This provides an early warning, even before the temperature inside the freezer rises to much.
+===== 3D printing: =====
+{{ :xnorit:public:summary:frost:ksnip_20241013-133209.png?400|}}
+As this system is utilized in a very busy environment, I decided to go with a combination of aluminium shell and 3D printed covers for the IO. On the bottom are two neodinium magnets with each a pull-force of 3.3 kg, to keep the module neatly against the freezer.
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-===== PCB design =====
+===== Software and GUI =====
+{{ :xnorit:public:summary:frost:dashboard_full.png?400|}}
+I decided to use a mySQL database for data storage, combined with Grafana as GUI. I'm however in the process of merging all data in an Influx database for performance improvements.