By 2016, most people have got the hang of doing SMD soldering in the garage–at least for standard packaging. Ball Grid Array or BGA, however, remains one of the more difficult packages to work with [Colin O’Flynn] has an excellent video (almost 30-minutes, including some parts that are sped up) that shows exactly how he does a board with BGA.
Using a toaster oven to reflow solder isn’t a new idea. But [Sukasa] wanted something that had more features and improved appearace. So he married a Netduino, a toaster oven, and some solid state relays to made a clean-looking reflow oven. His goal was to have nothing look like an overt modification to a casual observer. Inside, however, the oven now has a network connection for system status via a Web browser or JSON.
The new brains of the oven are a Netduino Plus 2 and an I2C port expander that connects to a few extra I/O devices. The challenging I/O, though, is the heaters. When cold, the oven can draw over 16 amps, so a pair of 12A solid state relays
in parallel handle that load. There are also two fans: one to keep the electronics cool and another on software control. An IGBT allows the controller to pulse width modulate the fan’s output. A pair of MAX31855s read the thermocouples that report the temperature.
The controller was a mashup of the existing oven’s keypad and an add-on LCD display (see right). One thing we didn’t see was a schematic. Of course, you can read the code and figure out how it is all connected and (unless you use the exact same oven) you are probably going to need to modify things to suit your particular setup, anyway.
We’ve seen other good looking reflow oven and controller builds in the past, including one with a touchscreen. It is also worth noting that you can find reflow ovens at relatively low prices now if you don’t feel like rolling your own.
[Will] had a few reasons for turning a toaster oven into a reflow oven – he needed a project for an ECE lab, the lab’s current reflow oven was terrible, and the man is trying to keep [Will] down by not allowing toaster ovens in dorm rooms. What was born out of necessity actually turned into a great project – a reflow oven with touchscreen controls.
The toaster oven used for this build is a model [Will] picked up at Sears. It’s actually pretty unique, advertised as a ‘digital toaster’. This isn’t marketing speak – there’s actually a thermistor in there, and the stock toaster is closed loop. After disassembling the toaster and getting rid of the guts, [Will] whipped up a PCB for a Teensy 3.1 and the Adafruit capacative touch shield.
With the Teensy and touch screen, [Will] came up with an interface that looks ten times better than anything you would find on a Chinese auction site. It’s a great build, and since it’s kept in the electronics lab, will certainly see a lot of use.
[Ed] owns a 3-zone reflow oven (which he coincidently uses to manufacture reflow oven controllers), but its performance has gotten worse and worse over time. The speed of the conveyer belt became so inconsistent that most boards run through the oven weren’t completely reflowed. [Ed] decided to rip out the guts of the oven and replace it with an Arduino, solving the belt problem and replacing the oven’s user-unfriendly interface
When [Ed] was looking into his belt speed problem, he discovered that the belt motor was controlled by an adjustable linear regulator with no feedback. Although this seems a bit sketchy by itself, the motor also had some mechanical issues and [Ed] ended up replacing it entirely. After realizing that closed-loop speed control would really help make the oven more consistent, [Ed] decided to overhaul all of the electronics in the oven.
[Ed] wanted to make as little custom hardware as possible, so he started out with an Arduino Mega and some MAX31855’s that measure multiple thermocouples in the oven. The Arduino controls the belt speed and runs PID loops which control heating elements in each of the oven’s 3 zones. The Arduino can be programmed with different profiles (stored in EEPROM) which are made up of 3 zone temperatures and a conveyor speed. Don’t have a 3-zone oven of your own to hack? Check out some DIY reflow oven builds we’ve featured before.
The T-962A is a very popular reflow oven available through the usual kinda-shady retail channels. It’s pretty cheap, and therefore popular, and the construction actually isn’t abysmal. The controller for this oven is downright terrible, and [wj] has been working on a replacement firmware for the horribly broken one provided with this oven. It’s open source, and the only thing you need to update your oven is a TTL/UART interface.
[WJ] bought his T-962A even after seeing some of the negative reviews that suggested replacing the existing controller and display. This is not in true hacker fashion – there’s already a microcontroller and display on the board.
The new firmware uses the existing hardware and adds a very necessary modification: stock, the oven makes the assumption that the cold-junction of the thermocouples is at 20°C. The controller sits on top of an oven with two TRIACs nearby, so this isn’t the case, making the temperature calibration of the oven slightly terrible.
After poking around the board, [WJ] found an LPC2000-series microcontroller and a spare GPIO pin for a 1-wire temperature sensor. The temperature sensor is placed right next to the terminal block for the thermocouples for proper temperature sensing.
All the details of updating the firmware appear on a wiki, and the only thing required to update the firmware is a serial/USB/UART converter. A much better solution than ripping out the controller and replacing it with a custom one.
With a lot of people who are suddenly too cool for through hole and of course the a few generations of components that are only available in SMD packages, it’s no surprise the humble toaster oven has become one of the mainstays of electronic prototyping. You’re gonna need a controller to ramp up those temperatures, so here are two that do the job quite nicely.
[Nathan]’s Zallus Oven Controller is a bit different than other reflow controllers we’ve seen on Kickstarter. He’s offering three versions, two with different sized touch screen displays, and one that is controlled with a PC and push buttons. The display for these is beautiful, and of course you can program your own temperature profiles.
If Kickstarter isn’t your thing, [Dirk] created his own reflow controller. Like the Zallus, this has a graphical display, but its homebrew lineage means it should be simpler to maintain. It uses a K-type thermocouple, and unlike every other reflow controller we’ve ever seen, [Dirk] is actually checking the accuracy of his temperature probe.
No, reflow oven controllers aren’t new, and they aren’t very exciting. They are, however, tools to build much cooler stuff, and a great addition to any lab.
A reflow oven is one of the most useful tools you will ever have, and if you haven’t built one yet, now is as good a time as any. [0xPIT’s] Arduino based reflow oven controller with a graphic LCD is one of the nicest reflow controllers we’ve seen.
Having a reflow oven opens up a world of possibilities. All of those impossible to solder surface mount devices are now easier than ever. Built around the Arduino Pro Micro and an Adafruit TFT color LCD, this project is very straight forward. You can either make your own controller PCB, or use [0xPIT’s] design. His design is built around two solid state relays, one for the heating elements and one for the convection fan. “The software uses PID control of the heater and fan output for improved temperature stability.” The project write-up is also on github, so be sure to scroll down and take a look at the README.