Reflow toaster oven using an Arduino
A reflow oven comes in handy when you work regularly with SMT circuits. I’ve had the T-962A reflow oven for about a year now. While it has worked reasonably well, recently it has started showing some signs of aging.
First of all, the total reflow time is quite long, about 15-16 minutes. This is really slow. Worse even, occasionally the internal temperature sensor would have a hiccup and the boards would come out under-heated or over-heated. Also, I hate the built-in buzzer, which produces a very loud, high-pitched beep when reflow is completed. This is very annoying — since I keep the reflow oven outdoors, I didn’t want my neighbors to think the beep is my fire alarm. So it’s time to find an alternative / backup solution.
After some online research, I’ve decided to build a reflow toaster oven using an Arduino-based controller. Toaster oven is cheap and provides better, more even heating than a hot skillet. I know toaster oven reflowing has been blogged about everywhere, but I do want to give my version some bells and whistles to provide more convenience. For example, I typically keep the reflow oven outdoors on my porch while working in the basement. So I’d like to receive a remote notification when reflow is complete (no loud beep please!). Also, I’d like an automatic way to open the oven door and blow air into the oven to accelerate the cooling time. For remote notification, I’ve decided to use an 433MHz RF transmitter to send signals to a remote power socket. I have a lamp connected to the power socket, and this way I will get notified when reflow is done. For faster cool-down time, I will use a servo tied to the oven door handle with a string — rotating the servo shaft can pull the door open. I will also put a second remote power socket connected to a circulation fan to blow air into the oven. Since I am using remote power sockets anyways, I am going to throw in a third one for the oven. This way all power line devices are controlled by power sockets, so there is no messing around with cutting cables etc. If you want better reliability, you can certainly use a relay or an SSR. I just decided to go with RF power sockets for the convenience.
Here is the list of materials I used:
- Toaster oven (with convection fan for more even heating).
- Kitchen thermometer (you can also get similar ones from Target or Walmart).
- RF power sockets (set of three).
- RF transmitter and receiver pair.
- 2.32K 1% resistor (any value between 2.2K to 10K is fine. 5% is ok but 1% is better).
- Arduino (any version).
- 5V servo, such as this one.
- Circulation fan.
For more detail: Reflow toaster oven using an Arduino