Arduino based 12V temperature control

thingiverse

This custom Arduino-based temperature control housing was crafted during the development of my bespoke heated printbed for the Dremel Idea Builder (http://www.thingiverse.com/thing:1608745). The underlying PCB for the heated printbed already features a 100k NTC thermistor, as well as plugs for easy connection to temperature readout and power input. Unfortunately, I couldn't find a ready-made temperature controller that exactly matched this specific combination of 100k Ohm NTC thermistor and 500 Ohm resistor, so I designed my own temperature controller. If anyone discovers a better solution, please feel free to post a comment or link. Post-Printing Electronics Required Materials: * 1x Arduino Uno * 1x LCD panel (16x2 with I2C) (e.g. http://www.aliexpress.com/item/5pcs-lot-IIC-I2C-1602-LCD-module-provides-libraries-with-demo-code-Free-shipping/32246903105.html) * 1x 12V relay switch (e.g. http://www.aliexpress.com/item/J34-Free-Shipping-1-Channel-12V-Relay-Module-Expansion-Board-Low-Level-Trigger-for-Arduino-Relays/32398040416.html) * 1x 10k Ohm potentiometer (e.g. http://www.aliexpress.com/item/2-pcs-B10K-10K-ohm-Single-Linear-Taper-Ratory-Potentiometers/32240562957.html) * 1x low voltage plug (5.5 x 2.1mm) (e.g. http://www.aliexpress.com/item/20pcs-5-5-2-1MM-male-DC-plug-DC-plug-weld-free-surveillance-camera-power-connector/32525740296.html) * Loads of cables to connect the electronics to the Arduino * 2 x connectors for the internal 5v and ground cablining (e.g. https://www.amazon.com/dp/B0107SYYGU/) * 2 x connectors for the 12v cablining (e.g. https://www.amazon.com/dp/B01AO24O0A/) * Small screws for attaching the electronics to the printed housing The cabling is depicted in the uploaded JPG, and the Arduino code can be found in the HeatBedControllerV01.ino file (note: the code is currently set up for °C, not °F). Things to Mention * The 12V relay switch can be connected in two ways: relay ON without signal or relay OFF without signal. To avoid powering the heatbed while the controller is still setting up, I recommend connecting the 12V relay with the option relay OFF without signal. * If you connect the heatbed incorrectly to the heatbed controller, this may cause incorrect temperature reading and subsequently powering the heatbed to maximum temperature. Please check proper operation of the controller for a certain period of time before leaving it working unattended. * Proper working should also include checking with a thermal camera and/or infrared temperature measurement device whether the heatbed temperature is at the height the controller indicates. How I Designed This This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/88575tIcokf