Reflowduino - Wireless Reflow Controller Ecosystem

The Reflowduino project is a complete ecosystem of open-source hardware designed specifically for DIY reflow control!

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The Reflowduino project is a do-it-yourself (DIY) reflow ecosystem consisting of open-source hardware specifically built for wirelessly controlling your own reflow oven while maintaining full flexibility in programming, and offering a bunch of features, all with great documentation!


The Reflowduino project is an entire do-it-yourself (DIY) reflow ecosystem consisting of open-source hardware specifically built to make it easy to control reflow appliances and apply PID temperature control while maintaining full flexibility in programming and usage while offering a bunch of features.

The Problem

Do-it-yourself PCB designers are having to painstakingly solder surface-mounted components by hand which not only takes good eyes, stable hands, and a ton of patience, but is also really inefficient and never produces results quite as good as production-quality boards. Moreover, although there are small reflow ovens commercially available, their price tags are a bit stiff and they usually ship with proprietary software that can't be modified easily.

Fortunately with the Reflowduino ecosystem designers can build their own reflow oven setup for a fraction of the price of commercially-available reflow ovens and with the flexibility to change the code, add as many features as needed to make it as simple or as fancy as desired, and learn throughout the process! Since I'm a firm believer of great online resources having learned everything on my own aside from my Mechanical Engineering degree, I'm sharing all of this as completely open-source for everyone to enjoy, including EAGLE PCB files, Arduino IDE example code, sample Android app for Bluetooth control, and full tutorials on how to modify a toaster oven to start cookin’!

You can find all design files, example code, demo app, and wiki on the Reflowduino Github page!

That being said, I do offer the boards listed below for sale on my website and on Tindie. Each order helps me out a little bit in creating and sharing new projects with everyone! :)

The Reflowduino ecosystem includes multiple pieces of hardware which I'll describe below. Although best suited for PCB reflow applications, each one can be used not only for reflow purposes but also as standalone learning tools or for other applications!

Reflowduino Basic

The classic Reflowduino board is an all-in-one Arduino-compatible controller board that can easily transform a toaster oven into a reliable reflow oven! It sports a versatile ATmega32u4 microprocessor with micro USB programming interface, an integrated MAX31855 K-type thermocouple interface with noise filtering, Bluetooth Low Energy (BLE 4.0) for easy pairing with a mobile device, LiPo battery charging and status indication, and buzzer for playing your favorite melodies.

Reflowduino Pro

Although it is more or less retired due to a lack of user demand, there's another version, the Reflowduino Pro board which is just the Reflowduino Basic but with an added solid-state relay on-board:

ESP32 Add-On Module ("Reflowduino32")

With the onset of the ESP32 craze I also created an ESP32 "backpack" module that plugs into this common "DOIT" ESP32 development board to give it convenient thermocouple and relay interface for easy reflow control while still communicating over Bluetooth Low Energy, but this time using the ESP32's built-in Bluetooth.

Sidekick Relay Module

To make it super easy to control practically any high-power AC appliance I also designed a high-power solid-state relay module which I fondly dubbed the "Sidekick" because it perfectly complements the Reflowduino or Reflowduino32 boards for reflow applications.

Reflowduino Tech Specs

The Reflowduino comes in two varieties, the Reflowduino Basic which doesn’t include a solid-state relay (think Arduino Uno form factor), and Reflowduino Pro, which has a solid-state relay already mounted on-board. Below are some quick technical specifications for the Reflowduino:

  • ATmega32u4: This nifty little microcontroller is the same powerful brains of the well-known Arduino Leonardo with USB-to-serial conversion all handled inside the chip! The board operates at 3.3V, not 5V, so please use level shifters...
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  • 1 × Reflowduino The Reflowduino Pro comes with a solid-state relay already mounted and ready to go. The Reflowduino Basic doesn't have the relay so you would have to select your own relay or use the Solid-State Sidekick as the most simple method! You can also use the Reflowduino32 along with an ESP32 dev board instead of the Reflowduino.
  • 1 × Toaster Oven OR Hot Plate I personally used a cheap $20 toaster oven from Walmart, and it worked great! You could also use a hot plate, but please note that these may not be as good as toaster ovens for reflow, at least without doing some testing and software tweaks first!
  • 1 × Solid-State Sidekick Relay Module The Solid-State Sidekick is a single solid-state relay module that allows you to simply plug in the appliance you need to control as well as the two relay control wires from the Reflowduino via a screw terminal, and you're all set! This is by far the easiest and safest method.
  • 1 × "DOIT" ESP32 Dev Board You can find it here:
  • 1 × Reflowduino32 Add-On Module The Reflowduino32 plugs into the ESP32 dev board and gives it thermocouple and relay interface via two screw terminals for easy connection.

  • Hackaday Prize 2018 Finalist!!!

    Timothy Woo05/02/2018 at 19:08 0 comments

    Hackaday just announced in this post that i'm among the 20 finalists from the Open Hardware Challenge! Congrats to all the other awesome projects out there!

    Keep hacking!

    ~ Tim

  • ESP32 + Reflowduino32 Reflow Oven Tutorial

    Timothy Woo03/25/2018 at 23:19 0 comments

    Hey guys,

    I just uploaded a new Instructable on how to build your own reflow oven using a DOIT ESP32 dev board and the Reflowduino32 backpack module. Check it out here!



  • Reflowduino32 - The ESP32 Reflow "Backpack"

    Timothy Woo03/24/2018 at 21:41 0 comments

    Wazzup everyone!

    Today I successfully built and tested Reflowduino32, a cute little add-on board that plugs into the "DOIT" ESP32 dev board. I've uploaded the design files as well as a new Reflowduino32 demo sketch to get started right away using the ESP32's built-in Bluetooth capabilities.

    If people like this a lot I'll probably be offering the boards for sale on my website or on Tindie!

    ~ Tim

  • ESP32 Reflowduino Add-On!

    Timothy Woo03/15/2018 at 00:02 0 comments

    Hey guys,

    Pretty soon I'll be making an add-on "backpack" for a popular ESP32 development board that will be super easy to use with the Sidekick relay module to control practically any AC appliance via the ESP32's Bluetooth capabilities. As usual I'll provide full documentation and example code for that as well!

    Stay tuned for the latest updates and follow me on Twitter! (I finally got on social media!)



  • Reflowduino is Live on Indiegogo!

    Timothy Woo12/01/2017 at 05:15 0 comments

    Hey guys, I'm really excited to announce that Reflowduino is now live on Indiegogo! Check out the campaign here and be sure to share!

    Thanks for all the support!

  • Stocked up!

    Timothy Woo11/27/2017 at 17:34 1 comment

    Hey guys, as you know the Indiegogo campaign for Reflowduino is only 4 days away! As a quick update  I just received 12 of each PCB and have stocked up on parts as well. Looking forward to what's next!

    Again, please share this project and spread the word!



  • Reflowduino on Indiegogo!

    Timothy Woo11/20/2017 at 03:15 0 comments

    Hey guys, I'm happy to announce that I will be launching an Indiegogo campaign for the Reflowduino and Sidekick relay module on December 1st! Stay tuned for early bird specials, cool perks, and more! (Learn more)

  • Stocking up on Inventory!

    Timothy Woo11/12/2017 at 01:10 0 comments

    Hey guys!

    Please check out the products page and email me at if you're interested because I'm trying to estimate a head count for Reflowduino orders!

    Also stay tuned for an upcoming Indiegogo campaign sometime next month and be sure to share!


  • Reflowduino Design Update - Pad Isolation

    Timothy Woo11/08/2017 at 16:49 0 comments

    Some in this Hackaday post have voiced their concerns about voltage isolation on the Reflowduino Pro and said that they would feel better if there were more physical isolation between the relay output pads, such as a slot or cutout. Although the Reflowduino does meet the IPC-2221 spacing guidelines, I thought this might be a good idea!

    I just updated the Reflowduino to version 2.1 by adding a cutout in between the two relay output pads. I have uploaded these latest EAGLE files on Github.

    Thanks for everyone's input, and as always, feel free to comment and suggest!

  • Sidekick Relay Module Tested!

    Timothy Woo11/07/2017 at 04:31 0 comments

    The Solid-State Sidekick (previously "Toasty Relay Module") is now fully tested! Take a look at the updated documentation on the Reflowduino Github repo. The Sidekick can be ordered here (note: please email me if you want to order one since they're not officially in stock yet).

    You can see the Sidekick setup in action in this video.

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