Mini heating table

Mini Thermostatic Heating Platform
Engineering Connection: Mini Heating Platform
Source Code: Mini Heating Platform
Finished Product Video: Mini Heating Platform
Effect Video: Heating Effect
Background Introduction
Previously, I used a PTC heating plate for teppanyaki, but it required a 220V connection, which felt inconvenient and unsafe. Most of the time, I used small boards, and a mini heating platform was sufficient. So, I designed a mini one. Initially, I used a 333333, but found the component layout too restrictive and too small, so I switched to a 404033. The small size also presented challenges for control and display. A small screen could have been placed, but after consideration, it was removed. A touch button was placed on the front, used only for heating on/off (the actual design also included temperature adjustment and network configuration, but these were not implemented). Interfaces were retained, allowing for external I2C screens, physical buttons, and even encoders. The placement of these interfaces or the addition of a casing is left for interested parties to consider.
Features include:


WIFI control (currently AP, planned AP+STA dual mode, automatically switching AP when unable to connect to the internet, not yet implemented);


Touch button control (supports single click, double click, multi-click, long press; currently uses triple click to control the switch);


Three-light status display (power + status + heating);


PD 20V power supply (PD+QC, voltage selection is not implemented due to insufficient IO, directly uses the highest 20V voltage; if the power supply does not support 20V, it will increase to the highest supported voltage);


Maximum 50W heating (can be adjusted to 65W on the heating plate line, but this is sufficient for my needs, so I won't bother);


Fan-assisted cooling (probe conducts heat quickly, a fan is necessary; if the probe is replaced to optimize the heating power supply, the fan can be eliminated, but I haven't found a cost-effective probe or spring yet).


PT1000 temperature sampling (PT1000, PT1000, PT1000, don't mistake it for PT100).


Initial serial port upgrade; subsequent upgrades can be done via network. With a serial port upgrade module, power-off upgrades are possible.


Temperature control <280℃ (280℃ is roughly the limit at 50W; the temperature can be increased further at 65W, but the heating plate solder layer can't withstand it, so it's not very useful).


Operating current and voltage display (INA226 sampling; this can be removed if not needed or to reduce costs).


Finished product display:
internal structure
page control.
After power-on, mobile phones or computers search for Wi-Fi and connect to HeatPlatform; password: 12345678. After connecting, there are issues with accessing the configuration menu when
upgrading firmware (192.168.0.1) in the browser. Using an LDO as the temperature sampling reference source results in inaccurate temperatures, and fine-tuning has been done; the accuracy is questionable. For higher precision, a reference source could be added. I'm not very good at adjusting the PID, and temperature overshoot occurs. The PID cannot be debugged or configured via the page. Later, I'm considering adding automatic PID calibration, referencing the Marlin source code. During serial port downloads or after online upgrades and restarts, heating is accidentally activated briefly; the cause is currently unknown. The mobile browser's WebSocket connection is sometimes extremely slow, causing the page to be unusable for a period after opening. (Later, I'm considering using WebSocket for temperature display.) (Control switches back to AJAX) Automatic switching of network configuration mode is not yet implemented. In AP mode, the phone cannot connect to the external network, making it relatively troublesome to use. Manufacturing tutorial : Screws: M23 (28 pieces), M27 (4 pieces, 7-15mm are all acceptable) Copper pillars: M22.5 (8 pieces), M24 (4 pieces), M28 (4 pieces), M211 (4 pieces) Fan: 2507 or 3007, if the thickness is 10mm, it can barely fit, but the heat dissipation effect is not good. Probe: Huarong P100-H2 Torx head (or other heads, I polished the Torx head to prevent piercing the copper foil) Insulation cotton: Aluminum silicate fiber paper (not as sharp as fiberglass, but still has a small number of needle-like crystals, use with care) Other components as originally For PCB prototyping, select three lines for drawing. The control board should be 1.0mm thick, and the others 1.6mm. Other lines are unnecessary . Compilation tools: VS Code + PlatformIO (Arduino can also be used; the required library files are in the lib_deps file of platformio.ini in the root directory, but this has not been tested). Download tool: TTL serial cable. It's uncertain how many people are involved, so a detailed tutorial won't be provided yet. If more people join, we'll update the log later as needed. Updated 2023-11-08: Added BOM form. Products in the form are actual products used, but authenticity and lowest price are not guaranteed. Those concerned about authenticity or price should replace the form themselves.