When interfacing with the real world, there are all kinds of sensors available which will readily communicate with your microcontroller of choice. Moisture, pH, humidity, temperature, location, light, and essentially every other physical phenomenon are readily measured with a matching sensor. But if you don’t have the exact sensor you need, it’s sometimes possible to use one sensor as a proxy for another.
[Brian Wyld] needed a way to monitor the level of a remote body of water but couldn’t use a pressure or surface-level sensor, so he used a sensor typically intended for geolocation instead. This particular unit, an STM-type device with a built-in accelerometer, is attached to a rotating arm with a float at one end. As the arm pivots, the microcontroller reports its position and some software converts the change in position to a water level. It’s also paired with a LoRa radio, allowing it to operate off-grid.
Whether there is a design requirement to use an esoteric sensor to measure something more common, or a personal hardware limitation brought about by a shallow parts drawer, there’s often a workaround like this one that can accomplish the job. Whatever the situation, we do appreciate hacking sensors into other types of sensors just as much as anything else.
Pivots for e-textiles can seem like a trivial problem. After all, wires and fabrics bend and flex just fine. However, things that are worn on a body can have trickier needs. Snap connectors are the usual way to get both an electrical connection and a pivot point, but they provide only a single conductor. When [KOBAKANT] had a need for a pivoting connection with three electrical conductors, they came up with a design that did exactly that by using a flexible circuit board integrated to a single button snap.
This interesting design is part of a solution to a specific requirement, which is to accurately measure hand movements. The photo shows two strips connected together, which pivot as one. The metal disk near the center is a magnet, and underneath it is a Hall effect sensor. When the wrist bends, the magnet is moved nearer or further from the sensor and the unit flexes and pivots smoothly in response. The brief videos embedded below make it clear how the whole thing works.
Continue reading “Three-Conductor Pivot For E-Textiles Is Better Than Wires”
A simple way to integrate physical feedback into a virtual experience is to use a fan to blow air at the user. This idea has been done before, and the fans are usually the easy part. [Paige Pruitt] and [Sean Spielberg] put a twist on things in their (now-canceled) Kickstarter campaign called ZephVR, which featured two small fans mounted onto a VR headset. The bulk of their work was in the software, which watches the audio signal for recognizable “wind” sounds, and uses those to turn on one or both fans in response.
The benefit of using software to trigger fans based on audio cues is that the whole system works independently of everything else, with no need for developers and software to build in support for your project, or to use other middleware. Unfortunately the downside is that the results are only as good as the ability of software to pick the right sounds and act on them. Embedded below is a short video showing a test in action.
Continue reading “Putting Wind In VR By Watching The Audio Signal”
This center pivot pen plotter is an interesting take on the idea, and manages to somewhat simplify the fabrication when compared to a gantry-style built.
Normally we’d see a gantry that travels on two rails, with a print head that moves along its length. Here the gantry is anchored on just one side, with a chain driven system to rotate it along the plotting surface. The print head uses a fine-point felt-tipped marker. It still travels along the arm as you would expect, and can be tilted away from the paper for repositioning.
What was made easier in hardware ends up adding to software complexity. The benefit of a traditional system is that it uses X and Y coordinates to plot a design. The pivot of this mechanism means that as the print head moves further from the center of the machine, the distance between each pixel is magnified. But the clip after the break proves that this issue has been solved.
Continue reading “Center Pivot Pen Plotter”