Reflow946

Fork notice — This is a modified version of Reflow946 by Arnaud Durand, licensed under the Creative Commons Attribution 4.0 International license (CC BY 4.0). See Modifications below for what changed.

The Reflow946 is a Bluetooth LE temperature controller for the 946C electronic hot plate. Using this controller, a reflow profile can be programmed from your web browser using the Web Bluetooth API. You can use preset profiles (e.g. for lead-free or leaded soldering) or create a custom profile for a perfect cheese fondue. 🫕

The controller board is intended to replace the original controller board. It is only compatible with the 3 buttons variant pictured above (see this teardown). Please send a PR if you adapted the design to a new variant.

The controller is based on a ESP32 module with an IPEX antenna. Since the metal case acts as a Faraday cage, the BLE signal can be improved by taping an antenna outside of the case.

• Temperature control
  • Temperature control using the front panel
  • BLE GATT service for temperature control
• Reflow profile programming
  • BLE GATT service for reflow profiles
  • Web Bluetooth application

Changes by Trent Rand (Randware), relative to upstream rev 1.2:

• Pathfinder revision (rev 2): 3-digit 7-segment display (DS1) replaced by a 1.47" IPS TFT (ST7789V3, 172x320) with two parallel interfaces: J6 FH12-8S-0.5SH FPC connector (v2 mounting path) and J9 2.54mm breakout header (bench bring-up). Signals ride the former segment-drive GPIOs: BL=dp(IO5) CS=f(IO23) DC=d(IO16) RES=g(IO13) SDA=c(IO19) SCL=d2(IO18). One display may be attached at a time (shared bus).
• Second MAX31855KASA (U6) with screw terminal J8 (EXT_TC) for top-of-PCB thermocouple profiling; shares CLK/MISO with the primary sensor, CS on IO4.
• Breakout J7 (CLK / MISO / CS_EXT / TC_ADC / 3V3 / GND): digital probe amps on the shared SPI bus, or analog amplifiers (AD8495) on TC_ADC = SENSOR_VP.
• IO17/IO22 left as spare GPIOs (I2C-capable; add pull-ups with the device).

Upstream hardware errata and revision notes are preserved in hardware/README.md.

• Arnaud Durand - Original design (CC BY 4.0)
• Elías Rodríguez Martín - Revision 1.1, conversion to KiCad
• Trent Rand (Randware) - OLED display interface, external probe interface