Want to know which way to point your WiFi antenna to get the best signal? It’s a guessing game for most of us, but a quick build of a scanning WiFi antenna using mostly off-the-shelf components could point you in the right direction.
With saturation WiFi coverage in most places these days, optimizing your signal might seem like a pointless exercise. And indeed it seems [shawnhymel] built this more for fun than for practical reasons. Still, we can see applications where a scanning Yagi-Uda antenna would come in handy. The build started with a “WiFi divining rod” [shawnhymel] created from a simple homebrew Yagi-Uda and an ESP8266 to display the received signal strength indication (RSSI) from a specific access point. Tired of manually moving the popsicle stick and paperclip antenna, he built a two-axis scanner to swing the antenna through a complete hemisphere.
The RSSI for each point is recorded, and when the scan is complete, the antenna swings back to the strongest point. Given the antenna’s less-than-perfect directionality — [shawnhymel] traded narrow beam width for gain — we imagine the “strongest point” is somewhat subjective, but with a better antenna this could be a handy tool for site surveys, automated radio direction finding, or just mapping the RF environment of your neighborhood.
Yagi-Uda antennas and WiFi are no strangers to each other, whether it be a WiFi sniper rifle or another recycling bin Yagi. Of course this scanner isn’t limited to WiFi. Maybe scanning a lightweight Yagi for the 2-meter band would be a great way to lock onto the local Ham repeater.
Continue reading “Simple Scanner Finds the Best WiFi Signal”
We so often hack for hacking’s sake, undertaking projects as a solitary pursuit simply for the challenge. So it’s nice to see hacking skills going to good use and helping someone out. Such was the case with this low-cost two-axis handheld camera gimbal intended to help a budding photographer with a motion disorder.
When [Tadej Strah] joined his school photography club, a fellow member who happens to have cerebral palsy needed help steadying cameras for clean shots. So rather than shell out a lot of money for a commercial gimbal, [Tadej] decided to build one for his friend. A few scraps of aluminum bar stock were bent into the gimbal frames and camera mount. Two hobby servos take care of the pitch and roll axes, controlled by an Arduino talking to an MPU-6050. Mounted to a handle from an angle grinder with the battery and electronics mounted below, the gimbal looks well-balanced and does a good job of keeping the camera level.
Hats off to [Tadej] for pitching in and solving a real world problem with his skills. We like to see people helping others directly, whether it’s building a gyroscopic spoon for Parkinson’s sufferers or vision enhancement for a nearly blind adventurer.
Continue reading “Scratch-built Camera Gimbal for Photographer with Cerebral Palsy”
What’s the best way to quickly move books from a vast underground archive to the library patrons who want to read them? For the New York Public Library (NYPL), it used to be an elaborate conveyor belt system. But the trouble with those is that the books will fall right off of them on a vertical run. What the NYPL’s gargantuan flagship library on 5th Avenue needed was a train to shuttle the books around. This week, as the majestic Rose Main Reading Room reopens after renovation, the train will leave the station.
From January to August 2016, workers retrofitted the existing conveyor belt infrastructure to support 950 feet of shiny, winding track. ‘Train’ is a bit of a misnomer because the cars travel singly. The double-track system traverses eight floors of library from the underground archive to any of the 11 designated stops. There are 24 book cars at present. Each one can hold about 30 pounds of books and travels at about 75 feet per minute.
In order to move between floors economically, some sections of track are completely vertical. How do the books stay in there? Simple—the cargo hold pivots on a gimbal. Sensors along the track make it easy to keep tabs on the cars, which are separated by a 15-second buffer to avoid collisions and mishaps. Click past the break for a sped-up demonstration. For you purists out there, we’ve also embedded the full, silent, real-time version that clocks in at nearly five minutes.
We like all kinds of trains around here, from the subterranean to the scientifically derailed.
Continue reading “The New York Public Library Built a Reading Railroad”
Warranty? We don’t need no stinking warranty! We’re hackers, and if you have access to a multi-million dollar CNC machine and 3D CAM software, you mill your own headphone replacement parts rather than accept a free handout from a manufacturer.
The headphones in question, Grado SR325s, are hand-built, high-end audiophile headphones, but [Huibert van Egmond] found that the gimbal holding the cups to the headband were loosening and falling out. He replicated the design of the original gimbal in CAM, generated the numeric code, and let his enormous Bridgeport milling machine loose on a big block of aluminum. The part was drilled and tapped on a small knee-mill, cut free from the backing material on a lathe, and bead-blasted to remove milling marks. A quick coat of spray paint – we’d have preferred powder coating or anodization – and the part was ready to go back on the headphones.
Sure, it’s overkill, but when you’ve got the tools, why not? And even a DIY CNC router could probably turn out a part like this – a lot slower, to be sure, but it’s still plausible.
Continue reading “High-end Headphones Fixed with High-end CNC Machine”
Sometimes, a person has a reason to track a target. A popular way to do this these days is with a camera, a computer, and software to analyze the video. But, that lends itself more to automated systems, like sentries. What if you want to be able to target something by “painting” it with a laser?
That’s exactly what [Jeremy Leaf] wanted to do, and the results are pretty impressive. He was able to track a .06 milliwatt laser at 2 meters. His design does this using three photodiodes in order to determine the position of a laser spot using triangulation.
Once the location of the laser spot has been determined, it can either simply be reported or it can be tracked. Tracking is achieved with a gimbal setup which updates quickly and accurately. Of course, it can only track the laser if the laser has something to be projected upon. If you need to track something in open 3D space, there are alternatives that would be better suited to the task.
Continue reading “Infrared Targeting On a Small Scale”
What can you do when you have a nice CNC machine, but build beautiful things like this 3-axis gimbal? We covered some of [Gal]’s work before, and he does not subscribe to the idea that hacks should look like hacks. If you’re going to spend hours and hours on something, why not make it better looking than anything you could buy off-the-shelf.
The camera is held stationary with three hollow shaft gimbal motors with low cogging. We weren’t aware of hollow shaft motors, but can think of lots of sensor mounts where such a motor could be used to make very compact and smooth sensor mounts instead of the usual hobby servo configuration. The brains are an off-the-shelf gimbal controller. The gimbal has a DB9 port at the back which handles charging of the internal LiPo batteries as well as giving him a place to input R/C signals for manual control.
The case is made from CNC’d wood and aluminum. There are lots of nice touches. For example, he added two buttons so he could fine tune the pitch of the gimbal. Each button is individually engraved with an up/down arrow.
[Gal] reverse engineered the connector on Garmin action camera he’s using so he can keep it powered, stream video, or add an external mic. Next he built a custom 5.8Ghz video transmitter based on a Boscam module. The transmitter connects to the DB9 charging port on the gimbal.
It’s very cool when someone builds something for themselves that’s far beyond anything they could buy. A few videos of it in operation after the break.
Continue reading “Very Pretty Gimbal With Long Feature List”
We’ve featured quite a few camera gimbals and steady cams here, but this one stands out. For one, [Daniel Rhyoo] was in his sophomore year when he built it. His 2-axis camera gimbal uses brushless DC motors, and is made out of carbon fiber.
[Daniel] machined the carbon fiber parts on a CNC desktop mill and some hand tools. And he also had to teach himself Solid Works to design it. In his slick DIY guide, he starts off by listing the parts and where to source them from, along with the tools needed. Most gimbals use servos for axis movements, which limits the range and do not provide very smooth motion. Brushless motors overcome these limitations allowing a nice, smooth moving gimbal to be built with a wide range of movement. When [Aleksey Moskalenko] introduced the AlexMos brushless motor controller, [Daniel] ordered it out, and then waited until he could get his hands on the right kind of motors. CAD files for all of the machined parts are available for download (.zip file).
He then goes on to blog his build progress, with ample photos to describe the machining and assembly. He does a couple of nice design choices along the way – like using press-nuts to make assembly and dis-assembly easy, and dismantling one of the motors and replacing its shaft with a custom, longer one instead of using a coupler to extend it. At the end, the result is not only a nice looking, light weight rig, but one that works very well thanks to the motors and controller that he used. Check out the video below to see it in action.
Continue reading “Homemade Camera Stabilizer”