A Thermometer Probe For A Hotplate, Plugging Stuff Into Random Holes

[NurdRage], YouTube’s most famous chemist with a pitch-shifted voice, is back with one of our favorite pastimes: buying cheap equipment and tools, reading poorly translated manuals, and figuring out how to do something with no instructions at all.

[NurdRage] recently picked up a magnetic stirrer and hotplate. It’s been working great so far, but it lacks a thermometer probe. [NurdRage] thought he was getting one with the hotplate when he ordered it, he just never received one. Contacting the seller didn’t elicit a response, and reading the terribly translated manual didn’t even reveal who the manufacturer was. Figuring this was a knock-off, a bit more research revealed this hotplate was a copy of a SCILOGEX hotplate. The SCILOGEX temperature probe would cost $161 USD. That’s not cool.

The temperature probe was listed in the manual as a PT1000 sensor; a platinum-based RTD with a resistance of 1000Ω at 0°C. If this assumption was correct, the pinout for the temperature probe connector can be determined by sticking a 1kΩ resistor in the connector. When the hotplate reads 0ºC, that’s the wires the temperature probe connects to.

With the proper pin connectors found, [NurdRage] picked up a PT1000 on eBay for a few dollars, grabbed a DIN-5 connector from a 20 year old keyboard, and connected everything together. The sensor was encased in a pipette, and the bundle of wires snaked down piece of vinyl tube.

For $20 in parts, [NurdRage] managed to avoid paying $161 for the real thing. It works just as good as the stock, commercial unit, and it makes for a great video. Check that out below.

Thanks [CyberDjay] for the tip.

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Gunpowder From Urine, Fighting A Gorn

[Cody] has a nice little ranch in the middle of nowhere, a rifle, and a supply of ammunition. That’s just fine for the zombie apocalypse, but he doesn’t have an infinite supply of ammo. Twenty years after Z-day, he may find himself without any way to defend himself. How to fix that problem? He needs gunpowder. How do you make that? Here’s a plastic jug.

There are three ingredients required to make gunpowder – saltpeter, charcoal, and sulfur. The last two ingredients are easy enough if you have trees and a mine like [Cody], but saltpeter, the a source of nitrates, aren’t really found in nature. You can make nitrates from atmospheric nitrogen if you have enough energy, but [Cody] is going low tech for this experiment. He’s saving up his own urine in a compost pile, also called a niter bed. It’s as simple as putting a few grass clippings and straw on a plastic tarp, peeing on it for a few months, and waiting for nitrogen-fixing to do their thing.

Calcium_nitrate
Calcium Nitrate

[Cody] doesn’t have to wait a year for his compost pile to become saturated with nitrates. He has another compost pile that has been going for about 18 months, and this is good enough for an experiment in extracting calcium nitrate. After soaking and straining this bit of compost, [Cody] is left with a solution of something that has calcium nitrate in it. This is converted to potassium nitrate – or saltpeter – by running it through wood ash. After drying out this mess of liquid, [Cody] is left with something that burns with the addition of a little carbon.

With a source of saltpeter, [Cody] only needs charcoal and sulfur to make gunpowder. Charcoal is easy enough to source, and [Cody] has a mine with lead sulfide. He can’t quite extract sulfur from his ore, so instead he goes with another catalyst – red iron oxide, or rust.

The three ingredients are combined, and [Cody] decides it’s time for a test. He has a homebuilt musket, or a piece of pipe welded at one end with a touch hole, and has a big lead ball. With his homebrew gunpowder, this musket actually works. The lead ball doesn’t fly very far, but it’s enough to put a dent in a zombie or deer; not bad for something made out of compost.

Historically, this is a pretty odd way of making gunpowder. For most of history, people with guns have also had a source of saltpeter. During the Napoleonic Wars, however, France could not import gunpowder or saltpeter and took to collecting urine from soldiers and livestock. This source of nitrates was collected, converted from calcium nitrate to potassium nitrate, and combined with charcoal and sulfur to field armies.

Still, [Cody] has a great example of what can be done using traditional methods, and the fact that he can fire a ball down a barrel is proof enough that the niter bed he’s peeing in will produce even better gunpowder.

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Pump Up the Volume with the 3D Printed Syringe Pump Rack

Syringe pumps are valuable tools when specific amounts of fluid must be dispensed at certain rates and volumes. They are used in many ways, for administering IV medications to liquid chromatography (LC/HPLC). Unfortunately, a commercial pump can cost a pretty penny. Not particularly thrilled with the hefty price tag, [Aldric Negrier] rolled up his sleeves and made a 3D-printed version for 300 USD.

[Aldric] has been featured on Hackaday before, so we knew his latest project would not disappoint. His 3D Printed Syringe Pump Rack contains five individual pumps that can operate independently of each other. Five pieces are 3D-printed to form the housing for each pump. In addition, each pump is composed of a Teflon-coated lead screw, an Arduino Nano V3, a Pololu Micro stepper motor driver, and a NEMA-17 stepper motor. The 3D Printed Syringe Pump Rack runs on a 12V power supply using a maximum of 2 amps per motor.

While the standard Arduino IDE contains the Stepper library, [Aldric] wanted a library that allowed for more precise control and went with the Accelstepper library. The 3D Printed Syringe Pump Rack has a measured accuracy of 0.5µl in a 10ml syringe, which is nothing to laugh at.

Syringe pump racks like [Aldric’s] are another great example of using open source resources and the spirit of DIY to make typically expensive technologies more affordable to the smaller lab bench. If you are interested in other open source syringe pump designs, you can check out this entry for the 2014 Hackaday Prize.

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Not Just a Floor Wax but an Embossing Powder!

The embossing process used in the creation of some of your fancier wedding invitations and business cards is an interesting one. It’s often called thermography or thermographic printing. Slow-drying, wet ink is applied to a substrate. The ink is dusted with a thermoplastic polymer called embossing powder, and a heat source raises the ink while drying it.

Commercial embossing powder costs about $10 an ounce. As [Ken] discovered, its manufacture is quite closed-source to boot. He set about creating his own embossing powder, and succeeded with a combination of commonly available floor finish and distilled white vinegar. A standard-sized bottle of floor finish yielded about four ounces of homemade embossing powder.

How does this work? The floor finish is an acrylic-based stable emulsion. Adding vinegar destabilizes the emulsion, decreasing its pH and setting the polymer free.  It’s a fairly fast process, which you can see in the second video that accompanies [Ken]’s write up. From there, it’s mostly a matter of straining the material, letting it dry, and pulverizing the coarse matter into powder. In the first video, [Ken] performs a comparison test of Ranger, a commercial powder, and his own concoction.

For a completely different take on home embossing, check out this soda-can-turned-keepsake-box.

Hackaday Prize Entry: Aspirin For Everyone

When it comes to the history of medicine and drugs, Aspirin, or more properly acetyl-salicylic acid, is one of the more interesting stories. Plants rich in salicalates were used as medicines more than four thousand years ago, and in the fourth century BC, [Hippocrates] noted a powder made from willow bark was an excellent analgesic. It was only in the 1800s that acetylated salicylic acid was first synthesized. In 1897, chemists at Bayer gave this ancient remedy a new name: Aspirin. It’s on the WHO List of Essential Medicines, but somehow millions of people don’t have access to this pill found in every pharmacy.

[M. Bindhammer] is working to make Aspirin for Everyone for his entry to the Hackaday Prize, using a small portable lab designed around chemicals that can be easily obtained.

The most common synthesis of Aspirin is salicylic acid treated with acetic anhydrate. Acetic anhydrate is used for the synthesis of heroin, and of course the availability of this heavily restricted by the DEA. Instead, [M. Bindhammer] will use a different method using salicylic acid and acetic acid. If you’re keeping track, that’s replacing a chemical on a DEA list of precursors with very strong vinegar.

[M. Bindhammer] even has a design for the lab that will produce the Aspirin, and it’s small enough to fit in a very large pocket. Everything that is needed for the production of acetyl-salicylic acid is there, including a reaction vessel with a heating element, a water/oil bath, flask, an Allihn condenser, and a vacuum filtering flask. Even if shipping millions of pills to far-flung reaches of the planet were easy, it’s still an exceptional Hackaday Prize entry.


The 2015 Hackaday Prize is sponsored by:

Measure as Little as You Want with openQCM

The clever folks over at [Novaetech SRL] have unveiled openQCM, their open-source quartz crystal microbalance. A QCM measures very minute amounts of mass or mass variation using the piezoelectric properties of quartz crystal. When an object is placed on the surface of this sensor, the changes in the crystal’s resonant frequency can be detected and used to determine its mass in a variety of experimental conditions (air, vacuum, liquid). However, most QCM technology is proprietary and pricey – at least US$3000 for the microbalance itself. Any consumables, such as additional crystals, cost several hundred dollars more.

The openQCM has a sensitivity of 700 picograms. At its core is an Arduino Micro with a custom PCB. The board contains a 10K thermistor for temperature offset readings and the driver for a Pierce oscillator circuit. The quartz crystal frequency is determined by hacking the timer interrupts of the Arduino’s ATmega32u4. An external library called FreqCount uses the clock to count the number of pulses of the TTL signal in a 1 second time frame. This yields quartz crystal frequency resolution of 1Hz. The user interface is built in Java so that data can be read, plotted, and stored on your computer. The entire casing is 3D-printed, and it appears that the sensors are standard oscillator crystals without their cases.

Simplistic design makes assembly and maintenance a breeze. It only weighs 55 grams. Replacing the quartz crystal requires no special tools due to the clip system. The openQCM can be used as a single unit, or in multiples to form a network for all of your precise measurement needs. While they have kits available that will set you back US$500, all of the files and schematics for 3D-printing, assembly, and the PCB are available on the openQCM site for free.

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Clever Chemistry Leads to Much Faster 3D Printing

Resin printing, it can be messy but you get really great resolution thanks to the optical nature of curing the sticky goo with light from a projector. Soon it will have a few more notches in its belt to lord over its deposition cousins: speed and lack of layers. A breakthrough in resin printing makes it much faster than ever before and pretty much eliminates layering from the printed structure.

The concept uses an oxygen-permeable layer at the bottom of the resin pool. This inhibits curing, and apparently is the source of the breakthrough. The resin is cured right on the border of this layer and allows for what is described as a continuous growth process rather than a layer-based approach. One of the benefits described is no need for resin to flow in as the part is extracted but we’re skeptical on that claim (the resin still needs to flow from somewhere). Still, for us the need to work with resin which is expensive, possibly messy, and has an expiry (at least when compared to plastic filament) has kept deposition as a contender. The speed increase and claims of strength benefits over layer-based techniques just might be that killer feature.

The technology is coming from a company called Carbon3D. They are branding it CLIP, or Continuous Liquid Interface Production. After the break you can see a video illustration of the concept (which is a bit too simple for our tastes) as well as a TED talk which the company’s CEO, [Joseph Desimone] gave this month. Of course there is also the obligatory time-lapse print demo.

So what do you think: game changer or not, and why do you feel that way? Let us know in the comments.

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