Continuing his tradition of making bits of wire and scraps of wood work wonders, [HomoFaciens] is back with a unique and clever design for an electromechanical encoder.
There are lots of ways to build an encoder, and this is one we haven’t seen before. Not intended in any way to be a practical engineered solution, [HomoFaciens]’ build log and the video below document his approach. Using a rotating disc divided into segments by three, six or eight resistors, the encoder works by adding each resistor into a voltage divider as the disc is turned. An Arduino reads the output of the voltage divider and determines the direction of rotation by comparing the sequence of voltages. More resistors mean higher resolution but decreased maximum shaft speed due to the software debouncing of the wiped contacts. [HomoFaciens] has covered ground like this before with his tutorial on optical encoders, but this is a new twist – sort of a low-resolution continuous-rotation potentiometer. It’s a simple concept, a good review of voltage dividers, and a unique way to sense shaft rotation.
Is this all really basic stuff? Yep. Is it practical in any way? Probably not, although we’ll lay odds that these encoders find their way into a future [HomoFaciens] CNC build. Is it a well-executed, neat idea? Oh yeah.
Continue reading “Wheel of Resistors Form Unique Rotary Encoder”
On the surface, a cup of tea is a simple thing to make. Heat up some water, insert tea leaves, and wait for it to steep. The wait time is a matter of taste, and it is absolutely crucial to remove the bag or infuser before it’s too late. Otherwise, you end up with a liquid that’s almost, but not quite, entirely unlike tea.
[Adrian] and his son would often find themselves lost in conversation during the steeping process and let it go too long. But that was before they built ChaiBot, an automatic tea minder. This fine-looking machine uses an old CD drive to raise and lower the tea bags, which are held by a thin piece of stainless steel mesh. Once the bags are lowered, [Adrian] pours hot water into the cups. The weight of the water is detected by a capacitive sensor under the cup cutouts, and this triggers the timer to start counting down to the perfect cuppa.
One of the coolest features of ChaiBot is the built-in circulation. Every minute, the bags are lifted out briefly and reinserted, disturbing the water so the steeping is more uniform. Since the final step to making great tea is drinking it before it goes cold, ChaiBot sends a push notification to [Adrian]’s phone. Be sure to check out the demo after the break.
Here’s another CD drive-based tea bot we covered a while back. It’s not quite as pretty, but it gets the job done. If you’re not one to wander off while your tea steeps but prefer not to watch a clock, here’s a compact timer that’ll fit in your pocket.
Continue reading “ChaiBot: A Tea Robot Steeped in Utility”
One of the redeeming qualities of many modern cheap keyboards is the built-in volume control buttons. But this is Hackaday, and many of us (and you) have Model Ms or newfangled mechanical keyboards that only have the essential keys. Those multimedia buttons only adjust the system volume anyway. We would bet that a lot of our readers have sweet sound systems as part of their rig but have to get up to change the volume. So, what’s the solution? Build a color-changing remote USB volume knob like [Markus] did.
Much like the Instructable that inspired him, [Markus] used a Digispark board and a rotary encoder. The color comes from a WS2812 LED ring that fits perfectly inside a milky plastic tub that once held some kind of cream. When the volume is adjusted, the ring flashes white at each increment and then slowly returns to whatever color it’s set to. Pushing the button mutes the volume.
The components are pretty lightweight, and [Markus] didn’t want the thing sliding all over the desk. He took an interesting approach here and filled the base with the lead from a shotgun round and some superglue. The rotating part of the button needed some weight too, so he added a couple of washers for a satisfying feel. Be sure to check out the demonstration after the break.
Digispark board not metal enough for you? Here’s a volume knob built around a bare ATtiny85 (which is the same thing anyway).
Continue reading “Pump Up the Volume with Lead Shot and LEDs”
Rotary encoders are pretty interesting pieces of technology. They’re a solid way to accurately measure rotation including the direction. [David] recently wrote some software to handle these input devices, but unlike everyone else, his application can get by on only one microcontroller pin.
Most people will use three pins to handle a rotary encoder with a microcontroller: one to handle the switch and two to handle the quadrature inputs. With only one pin left available on his project [David] had to look for another solution, and he focused on the principle that the encoder pins behaved in very specific ways when turning the shaft. He designed a circuit that generates an analog voltage based on the state of those pins. He also wrote a program that can recognize the new analog patterns produced by his rotary encoder and his new circuit.
If you’ve been stuck on a project that uses a rotary encoder because you’ve run out of pins, this novel approach may help you get un-stuck. It’s a pretty impressive feat of circuit design to boot. Just think of how many other projects use these types of input devices and could benefit from it!
[via Hackaday.io Project Page go give it a Skull!]
When you look at the current methods of scanning 2D and 3D objects available today, you’re basically looking at an imaging process. Either you take a picture of a 2D object, or you grab a blob of point clouds with a 3D scanner and make a 3D object that way. It wasn’t always like this – real, hardware 3D digitizers were used all the way back in the 70s, and touch probes are standard equipment on high-end CNC machines.
[Nikolaj Møbius] needed a way to record points in physical space, and not wanting to deal with the problems of images, he made an open source DIY digitizer. It’s basically a laser cut arm with rotary encoders at each joint. By reading the rotary encoders with an Arduino, [Nikolaj] can digitize a few points on a workpiece – just enough to make a bracket, or find the critical dimensions of a part.
It’s a great tool for when you need a little more information than a set of calipers can provide, and a great example of some ancient tech made useful again.
Continue reading “An Open Source, DIY Digitizer”
[shantea] builds MIDI controllers, and after a successful first endeavor with a matrix of buttons and knobs, he decided to branch out to something a little bit cooler. It’s called Ceylon, and it’s effectively a turntable controller built from an old hard drive.
As a contrast to the first MIDI controller, this would be a stripped-down build, with just three faders, LEDs for eye candy, a pair of pots for gain control, and a hard disk surrounded by six anti-vandal buttons. The hard disk is the star of the show, acting as a rotary encoder.
When manually spun, the hard disk generates a few phases of sinusoidal waves. The faster you spin it, the higher the amplitude and frequency. These signals are far too weak to be sampled directly by a microcontroller, and for digital control – as in, MIDI – you don’t need to read the analog signals anyway. These signals were turned digital with the help of an LM339 quad comparator. With two of these comparators and signals out of the hard disk that are 90 degrees out of phase, quadrature encoding is pretty easy.
The software for this MIDI controller is based on the OpenDeck Platform, a neat system that allows anyone to create their own MIDI controllers and devices. It’s also a great looking board that seems to perform well. Video below.
Continue reading “The Hard Drive MIDI Controller”
[Patrick] was looking for an easier way to control music and movies on his computer from across the room. There is a huge amount of remote control products that could be purchased to do this, but as a hacker [Patrick] wanted to make something himself. He calls his creation, “Dial” and it’s a simple but elegant solution to the problem.
Dial looks like a small cylindrical container that sits on a flat surface. It’s actually split into a top and bottom cylinder. The bottom acts as a base and stays stationary while the top acts as a dial and a push button. The case was designed in SOLIDWORKS and printed on a 3D printer.
The Dial runs on an Arduino Pro mini with a Bluetooth module. The original prototype used Bluetooth 2.0 and required a recharge after about a day. The latest version uses the Bluetooth low energy spec and can reportedly last several weeks on a single charge. Once the LiPo battery dies, it can be recharged easily once plugged into a USB port.
The mechanical component of the dial is actually an off-the-shelf rotary encoder. The encoder included a built-in push button to make things easier. The firmware is able to detect rotation in either direction, a button press, a double press, and a press-and-hold. This gives five different possible functions.
[Patrick] wrote two pieces of software to handle interaction with the Dial. The first is a C program to deal with the Bluetooth communication. The second is actually a set of Apple scripts to actually handle interaction between the Dial and the various media programs on his computer. This allows the user to more easily write their own scripts for whatever software they want. While this may have read like a product review, the Dial is actually open source! Continue reading “Dial is a Simple and Effective Wireless Media Controller”