Updated & Back in Stock – Reflow Oven Shield Controller

We have the new version of Reflow Oven Controller Shield back in stock. This version uses the new MAX31855KASA+ thermocouple interface chip replacing the old MAX6675.We made several changes to the original design in this latest version:

• Replaced the obsolete MAX6675 with MAX31855KASA+:
  • The newer chip allows measurement of temperature below 0 °C but will be prone to noise if proper filtering is not added. We added some filtering to the inputs of the chip as recommended by Maxim.
• Reassign pin usage:
  • I2C (A4 & A5) pins and D0-D3 are now available for user to add extra circuitry. If you want to add servo motor to control the oven door or if your oven needs to talk like Darth Vader, feel free to use these pins!
• Breakout pins for LED and push buttons:
  • If you ever need to mount external LED or push buttons on a panel, these breakout pins will make your life easier!
• Transistor output to drive external SSR.
• Bigger and taller push buttons for easier access.
• External SSR port for fan control and second indicator LED (green) are removed.
• Lower cost:
  • We managed to lowered the price a little although we were a little bit disappointed for not being able to push further down. Despite the lower cost of MAX31855KASA+ compared to the MAX6675, we also added proper logic translation IC (instead of resistor divider), 3.3 V LDO, filtering and ESD protection. This pretty much covers back the overall cost reduction introduced by the MAX31855KASA+ as we are still making them at low 200 quantity.