Exploring The Science Behind Dirty Air Filters

August 18, 2019 by Tom Nardi 34 Comments

Obviously, if the air filters in your home HVAC system are dirty, you should change them. But exactly how dirty is dirty? [Tim Rightnour] had heard it said that if you didn’t change your filter every month or so, it could have a detrimental effect on the system’s energy consumption. Thinking that sounded suspiciously like a rumor Big Filter™ would spread to bump up their sales, he decided to collect his own data and see if there was any truth to it.

There’s a number of ways you could tackle a project like this, but [Tim] wanted to keep it relatively simple. A pressure sensor on either side of the filter should tell him how much it’s restricting the airflow, and recording the wattage of the ventilation fan would give him an idea on roughly how hard the system was working.

Now [Tim] could have got this all set up and ran it for a couple months to see the values gradually change…but who’s got time for all that? Instead, he recorded data while he switched between a clean filter, a mildly dirty one, and one that should have been taken out back and shot. Each one got 10 minutes in the system to make its impression on the sensors, including a run with no filter at all to serve as a baseline.

The findings were somewhat surprising. While there was a sizable drop in airflow when the dirty filter was installed, [Tim] found the difference between the clean filter and mildly soiled filter was almost negligible. This would seem to indicate that there’s little value in preemptively changing your filter. Counter-intuitively, he also found that the energy consumption of the ventilation fan actually dropped by nearly 50 watts when the dirty filter was installed. So much for a clean filter keeping your energy bill lower.

With today’s cheap sensors and virtually infinite storage space to hold the data from them, we’re seeing hackers find all kinds of interesting trends in everyday life. While we don’t think your air filters are spying on you, we can’t say the same for those fancy new water meters.

Robot + Trumpet = Sad Trombone.mp3

October 22, 2018 by Kristina Panos 13 Comments

[Uri Shaked] is really into Latin music. When his interest crescendoed, he bought a trumpet in order to make some energetic tunes of his own. His enthusiasm flagged a bit when he realized just how hard it is to get reliably trumpet-like sounds out of the thing, but he wasn’t about to give up altogether. Geekcon 2018 was approaching, so he thought, why not make a robot that can play the trumpet for me?

He scoured the internet and found that someone else had taken pains 20 years ago to imitate embouchure with a pair of latex lips (think rubber glove fingers filled with water). Another soul had written about measuring air flow with regard to brass instruments. Armed with this info, [Uri] and partners [Ariella] and [Avi] spent a few hours messing around with air pumps, latex, and water and came up with a proof of concept that sounds like—and [Uri]’s description is spot-on—a broken robotic didgeridoo. It worked, but the sound was choppy.

Fast forward to Geekcon. In a flash of brilliance, [Avi] thought to add capacitance to the equation. He suggested that they use a plastic box as a buffer for air, and it worked. [Ariella] 3D printed some fingers to actuate the valves, but the team ultimately ended up with wooden fingers driven by servos. The robo-trumpet setup lasted just long enough to get a video, and then a servo promptly burned out. Wah wahhhh. Purse your lips and check it out after the break.

If [Uri] ever gets fed up with the thing, he could always turn it into a game controller a la Trumpet Hero.

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See The Fabulous Workmanship In This Smart Pressure Regulator

August 28, 2018 by Donald Papp 8 Comments

For many projects that require control of air pressure, the usual option is to hook up a pump, maybe with a motor controller to turn it on and off, and work with that. If one’s requirements can’t be filled by that level of equipment and control, then it’s time to look at commercial regulators. [Craig Watson] did exactly that, but found the results as disappointing as they were expensive. He found that commercial offerings — especially at low pressures — tended to leak air, occasionally reported incorrect pressures, and in general just weren’t very precise. Out of a sense of necessity he set out to design his own electronically controlled, closed-loop pressure regulator. The metal block is a custom manifold with valve hardware mounted onto it, and the PCB mounted on top holds the control system. The project logs have some great pictures and details of the prototyping and fabrication process.

This project was the result of [Craig]’s work on a microfluidics control system, conceived because he discovered that much of the equipment involved in these useful systems is prohibitively expensive for small labs or individuals. In the course of developing the electronic pressure regulator, he realized it could have applications beyond microfluidics control, and created it as a modular device that can easily be integrated into other systems and handle either positive or negative pressure. It’s especially well-suited for anything with low air requirements and a limited supply, but with a need for precise control.

Putting More Tech Into More Hands: The Robin Hoods Of Hackaday Prize

July 9, 2018 by Roger Cheng 9 Comments

Many different projects started with the same thought: “That’s really expensive… I wonder if I could build my own for less.” Success is rewarded with satisfaction on top of the money saved, but true hacker heroes share their work so that others can build their own as well. We are happy to recognize such generosity with the Hackaday Prize [Robinhood] achievement.

Achievements are a new addition to our Hackaday Prize, running in parallel with our existing judging and rewards process. Achievements are a way for us to shower recognition and fame upon creators who demonstrate what we appreciate from our community.

Fortunately there is no requirement to steal from the rich to unlock our [Robinhood] achievement, it’s enough to give away fruits of price-reduction labor. And unlocking an achievement does not affect a project’s standings in the challenges, so some of these creators will still collect coveted awards. The list of projects that have unlocked the [Robinhood] achievement will continue to grow as the Hackaday Prize progresses, check back regularly to see the latest additions!

In the meantime, let’s look at a few notable examples that have already made the list:

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Programmable Air Makes Robotics A Breeze

May 24, 2018 by Kristina Panos 10 Comments

[Amitabh] was frustrated by the lack of options for controlling air pressure in soft robotics. The most promising initiative, Pneuduino, seemed to be this close to a Shenzhen production run, but the creators have gone radio silent. Faced with only expensive alternatives, he decided to take one for Team Hacker and created Programmable Air, a modular system for inflatable and vacuum-based robotics.

The idea is to build the cheapest, most hacker-friendly system he can by evaluating and experimenting with all sorts of off-the-shelf pumps, sensors, and valves. From the looks of it, he’s pretty much got it dialed in. Programmable Air is based around $9 medical-grade booster pumps that are as good at making vacuums as they are at providing pressurization. The main board has two pumps, and it looks like one is set to vacuum and the other to spew air. There’s an Arduino Nano to drive them, and a momentary to control the air flow.

Programmable Air can support up to 12 valves through daughter boards that connect via right-angle header. In the future, [Amitabh] may swap these out for magnetic connections or something else that can withstand repeated use.

Blow past the break to watch Programmable Air do pick and place, control a soft gripper, and inflate a balloon. The balloon’s pressurization behavior has made [Amitabh] reconsider adding a flow meter, but so far he hasn’t found a reasonable cost per unit. Can you recommend a small flow meter that won’t break the bank? Let us know in the comments.

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Repair Job Fixes Compressor, Gets It Online

November 5, 2017 by Dan Maloney 35 Comments

We’ll never cease to be amazed at the things people try to put on the Internet of Things. Some are no-brainers, like thermostats, security cameras, and garage door openers. Others, like washing machines and refrigerators, are a little on the iffy side, but you can still make a case for them. But an IoT air compressor? What’s the justification for such a thing?

As it turns out, [Boris van Galvin] had a pretty decent reason for his compressor hacks, and it appears that the IoT aspect was one of those “why not?” things. Having suffered the second failure of his compressor’s mechanical pressure switch in a year, and unwilling to throw good money after the $120 that went into replacing the first contactor, [Boris] looked for a cheaper and more interesting way to control the compressor. An ESP8266 dev board made interfacing the analog pressure sensor a snap, and while he was at it, [Boris] added a web interface with a nice graphical air pressure gauge and some on-off controls. Now he can set the pressure using his phone and switch it off in the middle of the night without going outside. That’s an IoT win right there.

No air compressor? No worries — build your own from an old fridge. The non-IoT kind, preferably.

Toy Car Pumps The Wheels With Balloon Power

March 16, 2017 by Mike Szczys 21 Comments

We’ve had our eye on [Greg Zumwalt]. He’s been working on some very clever 3D-printed mechanisms and his latest prototype is an air engine for a toy car. You can supply the air for the single cylinder with a compressor, or by blowing into it, but attaching an inflated balloon makes the system self-contained.

Last week we saw the prototype of the engine by itself, and wondered if this had enough power to drive a little train engine. We were almost right as here it is powering the front wheels of a little car.

This isn’t [Greg’s] first rodeo. He’s been working on self-contained locomotion for a while now. Shown here is his spring-driven car which you pull backwards to load the spring. It’s a common feature in toys, and very neat to see with the included 3D-printed spring hidden inside of the widest gear.

That print looks spectacular, but the balloon-powered prototype tickles our fancy quite a bit more. Make sure you have your sound on when you watch the video after the break. It’s the chuga-chuga that puts this one over the top. [Greg] hasn’t yet posted files so you can print your own (it’s still a prototype) but browse the rest of his designs as you wait — they’re numerous and will bring an even bigger smile to your face. Remember that domino-laying LEGO bot [Matthias Wandel] built a few years back? [Greg] has a printable model for it!

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