DIY Barometer: It’s For Your Health!

October 27, 2017 by James Hobson 13 Comments

[Taciuc Marius] and his colleague noticed that days with low atmospheric pressure plus caffeine in their system meant a spike in blood pressure. Considering how this might impact his cardiovascular health, he decided to make a relative pressure barometer out of a jar to help him decide whether he should really have another cup of coffee.

Aside from a 3D printer, you’ll need to assemble a small jar with a lid, some screws, lock washers, nuts, and a flexible membrane — a piece of a rubber glove or balloon will do nicely. [Marius] details the build process on his project page, advising others to print the parts at 0.2 resolution — potentially even upping the extrusion multiplier to 1.1 — to prevent gaps in the print that would compromise the airtight seal needed for the barometer to work properly.

Additionally, thick glue or epoxy is recommended for the rest of the assembly process — it doesn’t have to be pretty, but it does need to be sealed! The final product can be easily tested by simply holding the jar.

While this barometer helps one make healthy choices, not all are created equal. This one tells you flat out how you should consider getting to work, while others have been tricked into behaving like touch sensors.

Electronics That Can Handle The Pressure

June 9, 2017 by Inderpreet Singh 11 Comments

Deep-sea exploration is considered as a relatively new area of research and the electronics involved has to be special in order to survive some of the deepest parts of the ocean. Pressure Tolerant Electronics is a new subject and has its own challenges as explained by [Nic Bingham] of the Schmidt Ocean Institute.

[Nic Bingham] was one of the speakers at the Supplyframe office for ‘The Hardware Developers Didactic Galactic’ held April 20th 2017. His talks was based on his experience with ambient-pressure electronics and autonomous solar-diesel power plants at the Antarctic plateau. Due to high pressures at large depths, the selection of components becomes critical. Low density components such as electrolytic capacitors have either air or fluids which are susceptible to compression under water and prone to damage. Since pressure tolerance is not part of most datasheet figures, component selection becomes difficult and subject to prior testing.

There are other challenges as well as [Nic Bingham] explains that revolve around the procurement of special parts as well as spare for older components. In his whitepaper, [Nic Bingham] chalks out everything from the development process to different testing methodologies and even component selection for such applications.

A video of his talk is worth a watch along with the nice writeup by [Chris Gammell] on his first hand experience of the lecture. For those who are looking for something on a budget, the underwater glider project is a good start. Continue reading “Electronics That Can Handle The Pressure” →

Soft-legged Robot Handles Rough Terrain With Ease

June 5, 2017 by Dan Maloney 9 Comments

Whether it’s wheels, tracks, feet, or even a roly-poly body like BB-8, most robots have to deal with an essential problem: dirt and grit can get into the moving bits and cause problems. Some researchers from UCSD have come up with a clever way around this: pneumatically actuated soft-legged robots that adapt to rough terrain.

At a top speed of 20 mm per second, [Michael Tolley]’s squishy little robot won’t set any land speed records. But for applications like search and rescue or placing sensors in inhospitable or inaccessible locations, slow and steady might just win the race. The quadrupedal robot’s running gear can be completely 3D-printed on any commercial printer capable of using a soft filament. The legs each contain three parallel air chambers within a bellowed outer skin; alternating how the chambers are inflated controls how they move. The soft legs adapt to unstructured terrain and are completely sealed, eliminating intrusion problems. The video below shows how the bot gets around just fine over rocks and sand.

The legs remind us a little of our [Joshua Vazquez]’s tentacle mechanism, but with fewer parts. Right now, the soft robot is tethered to its air supply, but the team is working on a miniaturized pump to make the whole thing mobile. At which point we bet it’ll even be able to swim.

Continue reading “Soft-legged Robot Handles Rough Terrain With Ease” →

Scissor Lift Shoes May Be OSHA Compliant

January 7, 2017 by Bryan Cockfield 30 Comments

It’s been said that necessity is the mother of all invention. This was probably the fundamental principle behind the show “Inspector Gadget”, a story about a police agent who has literally any technology at his grasp whenever he needs it. Although the Inspector’s gadgets get him into trouble more often than not (his niece Penny usually solves the actual crimes), the Inspector-inspired shoes that [Make it Extreme] built are a little bit more useful than whatever the Inspector happens to have up his sleeve (or pant leg, as the case may be).

If a fabrication tour de force, [Make it Extreme] built their own “Go Go Gadget Legs”, a set of pneumatically controlled stilts that allow the wearer to increase their height significantly at the push of a button. We often see drywall contractors wearing stilts of a similar height, but haven’t seen any that are able to raise and lower the wearer at will. The team built the legs from scratch, machining almost every component (including the air pistons) from stock metal. After some controls were added and some testing was done, the team found that raising one foot at a time was the safer route, although both can be raised for a more impressive-looking demonstration that is likely to throw the wearer off balance.

The quality of this build and the polish of the final product are incredibly high. If you have your own machine shop at home this sort of project might be within your reach (pun intended). If all you have on hand is a welder, though, you might be able to put together one of [Make it Extreme]’s other famous builds: a beer gun.

Continue reading “Scissor Lift Shoes May Be OSHA Compliant” →

Simple Fuel Pressure Alarm Averts Diesel Disaster

May 6, 2016 by Dan Maloney 42 Comments

If you could spend a couple of bucks on a simple project that might prevent a $2000 repair bill on your vehicle, you’d probably build it, right? That’s the idea behind this simple low-pressure alarm for a diesel fuel system, and it’s so simple it makes you wonder why the OEM didn’t do it.

We normally see [Bob Johnson] coming up with nifty projects (like this claw or this camera slider) that more often than not combine woodworking and electronics. But no tree carcasses were harmed in the making of this project. [Bob]’s goal is just to sound a warning and flash a light if the output of a pressure switch goes to ground. That indicates the lift pump in his Dodge Ram’s fuel tank has failed, which could lead to the sudden failure of the downstream injector pump for lack of lubrication by the fuel itself. His simple ATtiny85 circuit lives on a small perfboard in a 3D printed case and taps into a $30 fuel pressure switch. The microcontroller code enables a short delay to prevent nuisance alarms, and if the pressure drops below 5 PSI, [Bob] gets a chance to shut down the engine and disappoint his mechanic to the tune of $2000.

Maybe it’s planned obsolescence on the OEM’s part, or maybe it’s not. But kudos to [Bob] for a simple hack that averts a potentially expensive problem.

Continue reading “Simple Fuel Pressure Alarm Averts Diesel Disaster” →

Build Your Own Sensor Skin

February 29, 2016 by Dan Maloney 25 Comments

Scientific research, especially in the area of robotics, often leverages cutting-edge technology. Labs filled with the latest measurement and fabrication gear are unleashed on the really tough problems, like how to simulate the exquisite sensing abilities of human skin. One lab doing work in this area has taken a different approach, though, by building multi-functional sensors arrays from paper.

A group from the King Abdullah University of Science and Technology in Saudi Arabia, led by [Muhammad M. Hussain], has published a fascinating paper that’s a tour de force of getting a lot done with nothing. Common household items, like Post-It notes, kitchen sponges, tissue paper, and tin foil, are used to form the basis of what they call “paper skin”. Fabrication techniques – scissors and tape – are ridiculously simple and accessible to anyone who made it through kindergarten.

They do turn to a Circuit Scribe pen for some of their sensors, but even this nod to high technology is well within their stated goal of making it possible for anyone to fabricate sensors at home. The paper goes into great detail about how the sensors are made, how they interact, and how they are interfaced. It’s worth a read to see what you can accomplish with scraps.

For another low-tech paper-based sensor, check out this capacitive touch sensor keyboard.

Thanks for the tip, [Mattias]

Running Calculus On An Arduino

January 18, 2016 by Will Sweatman 39 Comments

It was Stardate 2267. A mysterious life form known as Redjac possessed the computer system of the USS Enterprise. Being well versed in both computer operations and mathematics, [Spock] instructed the computer to compute pi to the last digit. “…the value of pi is a transcendental figure without resolution” he would say. The task of computing pi presents to the computer an infinite process. The computer would have to work on the task forever, eventually forcing the Redjac out.

Calculus relies on infinite processes. And the Arduino is a (single thread) computer. So the idea of running a calculus function on an Arduino presents a seemingly impossible scenario. In this article, we’re going to explore the idea of using derivative like techniques with a microcontroller. Let us be reminded that the derivative provides an instantaneous rate of change. Getting an instantaneous rate of change when the function is known is easy. However, when you’re working with a microcontroller and varying analog data without a known function, it’s not so easy. Our goal will be to get an average rate of change of the data. And since a microcontroller is many orders of magnitude faster than the rate of change of the incoming data, we can calculate the average rate of change over very small time intervals. Our work will be based on the fact that the average rate of change and instantaneous rate of change are the same over short time intervals.