Face it — you want a reflow oven. Even the steadiest hands and best eyes only yield “meh” results with a manual iron on SMD boards, and forget about being able to scale up to production. But what controller should you use when you build your oven, and what features should it support? Don’t worry — you can have all the features with this open source reflow oven controller.

Dubbed the Reflowduino for obvious reasons, [Timothy Woo]’s Hackaday Prize entry has everything you need in a reflow oven controller, and a few things you never knew you needed. Based on an ATMega32, the Reflowduino takes care of the usual tasks of a reflow controller, namely running the PID loop needed to accurately control the oven’s temperature and control the heating profile. We thought the inclusion of a Bluetooth module was a bit strange at first, but [Timothy] explains that it’s a whole lot easier to implement the controller’s UI in software than in hardware, and it saves a bunch of IO on the microcontroller. The support for a LiPo battery is somewhat baffling, as the cases where this would be useful seem limited since the toaster oven or hot plate would still need a mains supply. But the sounder that plays Star Wars tunes when a cycle is over? That’s just for fun.

Hats off to [Timothy] for a first-rate build and excellent documentation, which delves into PID theory as well as giving detailed instructions for every step of the build. Want to try lower-end reflow? Pull out a halogen work light, or perhaps fire up that propane torch.

If you head down to your local electronics supply shop (the Internet), you can pick up a quality true-RMS multimeter for about $100 that will do almost everything you will ever need. It won’t be able to view waveforms, though; this is the realm of the oscilloscope. Unlike the multimeter’s realistic price point, however, a decent oscilloscope is easily many hundreds, and often thousands, of dollars. While this is prohibitively expensive for most, the next entry into the Hackaday Prize seeks to bring an inexpensive oscilloscope to the masses.

The multiScope is built by [Vítor] and is based on the STM32-O-Scope which is built around a STM32F103C8T6 microcontroller. This particular chip was chosen because of its high clock speed and impressive analog-to-digital resolution, which are two critical specifications for any oscilloscope. This particular scope has an inductance meter built-in as well, which is another feature which your otherwise-capable multimeter probably doesn’t have.

New features continue to get added to this scope by [Vítor]. Most recently he’s added features which support negative voltages and offsets. His particular scope is built inside of a model car, too, but we believe this to be an optional feature.

It seems like the multimeter is never easy to see during a project. Whether it’s troubleshooting a vehicle’s electrical system and awkwardly balancing the meter on some vacuum lines and the intake manifold, or installing a new solar panel and hoping the meter doesn’t fall on the ground while the leads are in both hands, it seems like there’s never a good way to see the meter while actually using it. Some meters have a small magnet and strap that can be used to hang them temporarily, but this will only get you so far.

[Alain Mauer]’s entry into the Hackaday Prize looks to solve this glaring problem. Using a heads-up Bluetooth display mounted to a pair of safety glasses, a multimeter can be connected to the device in order to display its information directly to its user. Based on his original idea which used a normal pair of prescription glasses as its foundation, [Alain]’s goal is to reduce safety hazards that might arise when using a multimeter in an awkward or dangerous manner that might not otherwise be possible.

The device uses an Arduino Pro Micro to connect to the multimeter and drive the display. [Alain] notes that the real challenge is with the optical system, however. Either way though, this would be a welcome addition to any lab, workspace, or electrician’s toolbox. Be sure to check out the video of it in action after the break.

It used to be hot air soldering gear was exotic, but not anymore. There are plenty of relatively inexpensive choices. Many of these appear to be the same despite having different brand names and model numbers. One that is common and inexpensive is the 858D. These run about $50. [Gabse] has one and decided to upgrade it using some open source controller hardware and software. There wasn’t a complete guide, so he created one himself.

According to the original GitHub page, the controller will work with the Youyue-858D and any clones. However, there are others like the Atten 858D that use a different controller. In addition, there have been several variants. [Gabse’s] guide is for the latest version. Information on other versions and brands might be on this discussion board thread.

The new controller and firmware offer better temperature regulation, a safety feature that prevents the handpiece from heating up if power is applied when the handpiece is not docked, fan fault detection, a cold air mode, a sleep mode, and more. There are PCBs available from OSH Park if you want to attempt it yourself. There are also a few YouTube videos showing the custom firmware, one of which appears below.

In addition to the controller change, [Gabse] shows you some optional tweaks to make the handpiece more robust, change the power plug, and make the cradle sensor more reliable. Worthwhile changes and all well-suited for the processing power of the Arduino.

We have gotten used to having the handpiece fixed on the bench, that’s another easy hack. You can also try an unholy union of soldering iron and articulated lamp.

If you had a choice between going to your boss and asking for funds for a new piece of gear, would you rather ask for $3000 to buy off-the-shelf, or $200 for the parts to build the same thing yourself? Any self-respecting hacker knows the answer, and when presented with an opportunity to equip his lab with a new DIY syringe pump for $200, [Dr. D-Flo] rose to the challenge.

The first stop for [Dr. D-Flo] was, naturally, Hackaday.io, which is where he found [Naroom]’s syringe pump project. It was a good match for his budget and his specs, but he needed to modify some of the 3D printed parts a little to fit the larger syringes he intended to use. The base is aluminum extrusion, the drive train is a stepper motor spinning threaded rod and a captive nut in the plunger holders, and an Arduino and motor shield control everything. The drive train will obviously suffer from a fair amount of backlash, but this pump isn’t meant for precise dispensing so it shouldn’t matter. We’d worry a little more about the robustness of the printed parts over time and their compatibility with common lab solvents, but overall this was a great build that [Dr. D-Flo] intends to use in a 3D food printer. We look forward to seeing that one.

It’s getting so that that you can build almost anything for the lab these days, from peristaltic pumps to centrifuges. It has to be hard to concentrate on your science when there’s so much gear to make.

There are two kinds of people in the world (and, no, this isn’t a binary joke). People who love the Arduino, and people who hate it. If you’ve ever tried to use a standard prototype board to mount on an Arduino, you’ll know what kind of person you are. When you notice the pins aren’t on 0.1 inch centers, you might think, “What the heck were those idiots thinking!” Or, you might say, “How clever! This way the connectors are keyed to prevent mistakes.” From your choice of statement, we can deduce your feelings on the subject.

[Rssalnero] clearly said something different. We weren’t there, but we suspect it was: “Gee. I should 3D print a jig to bend headers to fit.” Actually, he apparently tried to do it by hand (we’ve tried it, too). The results are not usually very good.

He created two simple 3D printed jigs that let you bend an 8-pin header. The first jig bends the correct offset and the second helps you straighten out the ends again. You can see the result in the picture above.

[Rssalnero] notes that the second jig needed reinforcement, so it is made to take 8 pins to use as fulcrums. Probably doesn’t hurt to print the jigs fairly solid and using harder plastic like ABS or PETG, too. Even if you don’t have a 3D printer, this is about a 15 or 30 minute print on any sort of reasonable printer, so make a friend. Worst case, you could have one of the 3D printing vendors make it for you, or buy local.

We love little tool hacks like this. If you are too lazy to snap 8 pins off a 40 pin strip, maybe you’d like some help. If you’d rather go with a custom PC board, you might start here.

A first-time visitor to any bio or chem lab will have many wonders to behold, but few as captivating as the magnetic stirrer. A motor turns a magnet which in turn spins a Teflon-coated stir bar inside the beaker that sits on top. It’s brilliantly simple and so incredibly useful that it leaves one wondering why they’re not included as standard equipment in every kitchen range.

But as ubiquitous as magnetic stirrers are in the lab, they generally come in largish packages. [BantamBasher135] needed a much smaller stir plate to fit inside a spectrophotometer. With zero budget, he retrofitted the instrument with an e-waste, Arduino-controlled magnetic stirrer.

The footprint available for the modification was exceedingly small — a 1 cm square cuvette with a flea-sized micro stir bar. His first stab at the micro-stirrer used a tiny 5-volt laptop fan with the blades cut off and a magnet glued to the hub, but that proved problematic. Later improvements included beefing up the voltage feeding the fan and coming up with a non-standard PWM scheme to turn the motor slow enough to prevent decoupling the stir bar from the magnets.

[BantamBasher135] admits that it’s an ugly solution, but one does what one can to get the science done. While this is a bit specialized, we’ve featured plenty of DIY lab instruments here before. You can make your own peristaltic pump or even a spectrophotometer — with or without the stirrer.

[via r/Arduino]

The team at [2PrintBeta] required a bunch of cables, heat shrink, and braid to be cut for their customers. They looked into an industrial cable cutter, but decided the price was a little too high, so they decided to make their own. They had a bunch of ideas for cutting: Using a razor blade?  Or a Dremel with a cutting wheel? What they came up with was a DIY cable cutter that uses a pair of scissors, a pair of stepper motors, a pair of 3D printed wheels and an Arduino.

The first thing the team had to do was to mount the scissors so they would cut reliably. One of the stepper motors was attached to a drive wheel that had a bolt mounted on it. This went through one of the scissors’ handles, the other handle was held in place on the machine using screws. The second stepper motor was used to rotate the wheels that drives the cable through to the correct length. [2PrintBeta] used a BAM&DICE shield and two DICE-STK stepper motor drivers on an Arduino Mega to control the cutter.

The [2PrintBeta] team are pretty good at doing things themselves, as we’ve seen previously with their DIY plastic bender. And again, with this automatic cable cutter, they’ve seen a need and resolved it using the things at their disposal and some DIY ingenuity.

[MakinStuff] wrote in to let us know about a project he did for new and improved interfacing to the ubiquitous cheap Chinese digital calipers. Interfacing to this common caliper model is well-trod ground, but his project puts everything about interfacing and reading the data in one place along with some improvements: a 3D printed connector that makes mating to the pads much more stable and reliable, a simple interface circuit for translating the logic levels, and an interrupt-driven sample Arduino sketch to read the data. Making the sketch interrupt-driven means the Arduino never sits and waits for input from the calipers, making it easier have the Arduino do other meaningful work at the same time, ultimately making it easier to incorporate into other projects.

The connector has spaces to insert bare wires to use as contacts for the exposed pads inside the calipers. Add a little hot glue and heat shrink, and you’ll never have to fiddle with a hacked-together connection again.

This common caliper model has been hacked and re-purposed in interesting ways. We’ve seen them used as a Digital Read Out (DRO) on a lathe as well as being given the ability to wirelessly log their data over Bluetooth.

[Mr_GreenCoat] is studying engineering. His thermodynamics teacher agreed with the stance that engineering is best learned through experimentation, and tasked [Mr_GreenCoat]’s group with the construction of a vacuum chamber to prove that the boiling point of a liquid goes down with the pressure it is exposed to.

His group used black PVC pipe to construct their chamber. They used an air compressor to generate the vacuum. The lid is a sheet of lexan with a silicone disk. We’ve covered these sorts of designs before. Since a vacuum chamber is at max going to suffer 14.9 ish psi distributed load on the outside there’s no real worry of their design going too horribly wrong.

The interesting part of the build is the hardware and software built to boil the water and log the temperatures and pressures. Science isn’t done until something is written down after all. They have a power resistor and a temperature probe inside of the chamber. The temperature over time is logged using an Arduino and a bit of processing code.

In the end their experiment matched what they had been learning in class. The current laws of thermodynamics are still in effect — all is right in the universe — and these poor students can probably save some money and get along with an old edition of the textbook. Video after the break.