If you are unfamiliar with Dune, then you may not know what the pain box is. The pain box is a fictional device that produces an excruciating burning sensation without causing any actual damage. [Bryan] has been working on a project to duplicate this effect in the real world. It sounds like he may be on the right path by using the “thermal grill illusion”.
The thermal grill illusion is a sensory trick originally demonstrated back in 1896. The trick is made up of two interlaced grills. One is cool to the touch, and the other is warm. If the user touches a single grill, they won’t experience any pain because neither temperature is very extreme. However if the user places their hand over the interlaced grills simultaneously they will immediately experience a burning heat. This usually causes the person to pull their hand away immediately. It’s a fun trick and you can sometimes see examples of it at science museums.
The thermal grill illusion sounded like the perfect way to make the pain box a reality. [Bryan] has set specific constraints on this build to make it more true to the Dune series. He wants to ensure the entire package fits into a small box, just big enough to place an adult hand inside. He also wants to keep safety in mind, since it has the potential to actually cause harm if it were to overheat.
[Bryan] has so far tried two methods with varying success. The first attempt involved using several thermoelectric coolers (TECs). [Bryan] had seen PCBs etched a certain way allowing them to radiate heat. We’ve seen this before in 3D printer surfaces. He figured if they could become hot, then why couldn’t they become cold too? His idea was very simple. He etched a PCB that had just two large copper pours. Each one branched out into “fingers” making up the grill.
Each side of the grill ultimately lead to a flat surface to which a TEC was mounted. One side was cold and the other was hot. Heat sinks we attached to the open side of the TECs to help with performance. Unfortunately this design didn’t work. The temperature was not conducted down to the fingers at all. The back side of the PCB did get hot and cold directly under the TECs, but that wouldn’t work for this illusion.
The latest version of the project scraps the PCB idea and uses small diameter copper tubing for the grill. [Bryan] is working with two closed loop water systems. One is for warm water and the other is for cold. He’s using an aquarium pump to circulate the water and the TECs to actually heat or cool the water. The idea is that the water will change the temperature of the copper tubing as it flows through.
While the results so far are better than the previous revision, unfortunately this version is having problems of its own. The hot water eventually gets too hot, and it takes over an hour for it to heat up in the first place. On top of that, the cold water never quite gets cold enough. Despite these problems, [Bryan] is hopefully he can get this concept working. He has several ideas for improvements listed on his blog. Maybe some Hackaday readers can come up with some clever solutions to help this project come to fruition.
Here’s a skill we should all probably have for after the apocalypse—the ability to build a cheap peristaltic pump that can transport highly viscous fluids, chunky fluids, or just plain water from point A to point B with no priming necessary. That’s exactly what [Jack Ruby] has done with some fairly common items.
He started with a springform cake pan from a thrift store, the kind where the bottom drops out like that centripetal force ride at the carnival. He’s using 2″ casters from Harbor Freight mounted to a block of wood. The casters go round and squeeze fluid through the hose, which is a nice length of heat-resistant silicone from a local homebrew shop. He’s currently using a drill to run the pump, but intends to attach a motor in the future.
[Jack]’s write-up is very thorough and amusing. Stick around to see the pump in action as well as a complete tour. You can also pump colored goo if you’re out of beer materials.
Continue reading “Peristaltic Pump Moves Fluids Uphill Both Ways”
You would think Hackaday would see more projects from public art exhibitions. They really do have everything – the possibility to mount electronics to just about anything in a way that performs interesting but an ultimately useless function. So far, though, [Richard Schwartz’s] Flow of Time is on the top of a very short list of public art installations we like.
The idea behind the build is a German phrase that means something similar to ‘time trickles away’. [Richard]’s project implements this by printing the current time onto the surface of a flowing river in [Richard]’s native Innsbruck.
The build uses five micro piezo pumps to dispense food coloring from a bridge. Every minute, an Arduino pumps this food coloring in a 5×7 pixel digit to ‘write’ the time onto the surface of a river.
Surprisingly, [Richard]’s installation doesn’t require much upkeep. The pumps only use about 70ml of food coloring a day, and the entire device – including the Raspi WiFi webcam – is solar powered with a battery backup.
You can see a video of the time printing on a river below.
Continue reading “The Flow Of Time Draws On A River”
Check out the tomato plants [Devon] grew using a monitoring system he built himself. It’s based around a Raspberry Pi. As far as grow controllers go it falls a bit short of full automation. That’s because the only thing it can actuate is the black water line seen hovering above the plants. But [Devon’s] work on monitoring and collecting sensor data should make it easy to add features in the future.
The moisture sensors pictured above monitor the soil in which the plants are growing. But he also has temperature and light sensors. These are very important when growing from seed and could be used in conjunction with a heating mat for plants that require higher soil temperatures (like pepper plants). The tomatoes are also pretty leggy. Now that he’s monitoring light levels it would be good to augment the setup with a grow light. A long term goal could even be a motorized bed which could raise the plants right up to the bulbs so they don’t reach for the light.
Don’t let the stars in our eyes distract you though. He’s done a ton of work on the project both with the physical build, and in plotting the data collected by the system. Great job!
Continue reading “Raspberry Pi automates your tomato farm”
This hack makes the virtual real by displaying your video game character’s health meter as a column of illuminated water.
The build video, which you’ll find embedded after the break, is really quite remarkable. The column is a clear piece of pipe anchored at one end by hand-tightened plumbing drain fittings. This allows [Bfayer] to attach a flexible bladder which he constructed for the project. An actuator pushes a hinged board up against the bladder to raise and lower the water level in the tube.
Alone that’s pretty impressive, but [Bfayer] went the extra mile and then some. He uses a four-way fitting at the bottom of the meter. One fork connects to the bladder, another allows air to be injected using an aquarium pump. The bottom of the fitting has a clear window so that an RGB LED array can shine into the water which was doped with highlighter ink to pick up the colored glow. To pull the whole thing together he coded the custom control interface seen above.
Continue reading “Life meter gives a real life measure of video game health”
[Ed] got pretty creative with a hack that adds a pressurized water tap to his Jeep Wrangler. The tap on the rear passenger bumper now lets him hose off the vehicle after mudding, rinse his SCUBA gear after a dive, and just generally comes in handy.
If you want running water you’ve got to have a place to put it. This is actually what sparked the idea for the project. [Ed] noticed that the bumper was hollow and had some drain holes on the bottom. After plugging those and adding a fill hole to the top he found that he had a reservoir for about seven gallons. To get the water out he added a pump deigned to be used on an RV. It’s got features that make it work perfectly for this application: it runs off of battery voltage, it will turn on and off automatically when the tap is opened based on water pressure, and it will shut itself off if the reservoir runs dry. He designed a bezel to give the spigot a professional look. Just out of frame in the image above is an attachment for pressurized air. His next planned project for the Jeep is to add an air compressor.
After the break you can see a demo of the installed system, as well as a water pump test.
Continue reading “Jeep Wrangler gets pressurized water right out of the bumper”
[Joel] made a brilliant improvement to his shop. If you think about it, most folks would hear a loud vacuum pump and either tolerate it or put in some ear plugs. But [Joel] heard a loud vacuum pump and thought: hey, I can fix that! His solution was to design and print his own muffler.
He did a bit of research on the topic and found that design complexity runs the gamut based on the application. For instance, you don’t want to affect the airflow of a vehicle’s exhaust too much or you will take a horsepower (and efficiency) hit for it. In this case the vacuum pump making all the noise has a relatively low airflow so that is not a concern. What he ended up doing is designing a baffle that will help cushion the vibrations in the airy by piping it through a maze of channels. The end result drops from about 92 dB to 82 dB. That might not seem like much, but decibel measurements aren’t linear so it ends up having a great effect. Hear for yourself in the video after the break.
Continue reading “Printed vacuum pump muffler quiets the lab”