Dispensing Solder Paste Automatically

Through-hole chips are slowly falling by the wayside, and if you want to build something with new parts you will be using surface mount components. This means spreading paste and throwing it in the toaster oven. Of course, if you don’t want to take the time to get a stencil for your solder paste, you can always lay it down by hand. For that, [owhite] has created a tiny, handheld, robotic solder paste dispenser. It’s a robotic pen that dispenses just the right amount of solder paste on your pads.

The design of this solder paste dispenser is basically a syringe filled with paste and a stepper motor to push the plunger down. Devices like this already exist, and the i-extruder can be had for somewhere around two hundred bucks. Why buy when you can build, so [owhite] set out to create his own.

The key to a successful solder paste pen, it seems, is driving the plunger with a small NEMA 8 stepper motor, using a very fine pitch on the threads of the gears pushing the plunger down, and surprisingly finding a small-diameter syringe. [owhite] found the last bit in the form of a gas-tight syringe with a nylon gasket. The electronics consist of just a Teensy 3.2, DRV8825 stepper driver, footswitch, and an OLED for a UI.

With just a few parts, [owhite] managed to create a solder paste pen that’s better than the commercial i-extruder, and with a bit of practice can be used to place paste on some SMD pads.

Meccano Piston Pump Made With a Syringe

[Mohamed Sami] built a syringe pump out of Meccano building set parts. It consists of a simple framework with a DC motor mounted on it that actuates the syringe when powered. A check valve harvested from an ordinary household spray bottle keeps the syringe from sucking back liquid that it has just pumped out, so it can keep pumping forever. A lead-acid battery powers the whole thing.

Syringe pumps are typically used to deliver precisely measured quantities of substances. Right now [Mohamed]’s rig is just an uncontrolled pump, but he hopes to get a better understanding of and control over how much liquid gets pumped. Adding an encoder to the DC motor would be a start, was his thought — or even better would be a stepper.

You’d be surprised how many syringe pump projects we publish. Not just another syringe pump, but simple hydraulic projects and even using the syringe barrel as a logic probe’s enclosure.

Super Simple Hydraulics Using Syringes

When making a toy excavator arm, or any robotic arm, the typical approach is to put motors at the joints, or if there isn’t room, to put the motors somewhere else and transfer the force using fishing line and pulleys. [Navin Khambhala] chose instead to do it more like the real excavators, with hydraulics using syringes. And we have to admit, the result it pretty elegant in its simplicity.

The syringes do the job of single-acting hydraulic actuators, one at the motor and the other where the force is needed. In between them, what appears to be clear vinyl tubes carry the fluid between syringes. 12 volt DC motors with bolts on them move nuts attached to the syringe pistons to push and pull the pistons. It is so simple that no further explanation is needed, though like most apparently simple things, we’re sure a lot of effort went into making it that way. The video below shows the finished product, as well as walks through the making of it.

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Precision Pressure In A Piston

[Scott] is building a DIY yeast reactor for his aquarium. What’s a yeast reactor? [Scott] wants to pump carbon dioxide into his aquarium so his aquatic plants grow more. He’s doing this with a gallon of sugary, yeasty water bubbling into a tank of plants and fish. In other words, [Scott] is doing this whole thing completely backward and utilizing the wrong waste product of the yeast metabolism.

However, along the way to pumping carbon dioxide into his aquarium, [Scott] created a very high precision pressure sensor. It’s based on a breakout board featuring the MS5611 air pressure sensor. This has a 24-bit ADC on board, which translates into one ten-thousandths of a pound per square inch of pressure.

To integrate this pressure sensor into the aquarium/unbrewery setup, [Scott] created a pressure meter out of a syringe. With the plunger end of this syringe encased in epoxy and the pointy end still able to accept needles, [Scott] is able to easily plug this sensor into his yeast reactor. The data from the sensor is accessible over I2C, and a simple circuit with an ATmega328 and a character LCD displays the current pressure in the syringe.

We’ve seen these high-resolution pressure sensors used in drones and rockets as altimeters before, but never as a pressure gauge. This, though, is a cheap and novel solution for measuring pressures between a vacuum and a bit over one atmosphere.

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LEGO Liquid Handler and Big Biology

A career as a lab biologist can take many forms, but the general public seems to see it as a lone, lab-coated researcher sitting at a bench, setting up a series of in vitro experiments by hand in small tubes or streaking out a little yeast on an agar plate. That’s not inaccurate at all – all of us lab rats have done time with a manual pipettor while trying to keep track of which tube in the ice bucket gets which solution. It’s tedious stuff.

But because biology experiments generally scale well, and because more data often leads to better conclusions, life science processes can quickly grow beyond what can be handled manually. I’ve seen this time and again in my 25 years in science, from my crude grad school attempts to miniaturize my assays and automate data collection to the multi-million dollar robotic systems I built in my career in the pharmaceutical industry. Biology can get pretty big in a hurry. Continue reading “LEGO Liquid Handler and Big Biology”

DIY Syringe Pump Saves Big Bucks for Hacker’s Lab

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.

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Solder Paste Dispenser has No 3D Printed Parts!

If you’ve never used a solder paste dispenser, you’re missing out. Think about always using a crappy soldering iron, and then for the first time using a high-end one. Suddenly you’re actually not bad at soldering things! It’s kind of like that.

Most solder paste dispensers make use of compressed air, which requires an extra setup to use that you might not have. The goal of this project was to make a solder paste dispenser that doesn’t use compressed air, and doesn’t have any 3D printed parts (in case you don’t have a 3D printer) — and it looks like the inventor, [MikeM], succeeded!

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