The coaster is built around an Arduino Micro, which uses a microphone to detect audio levels in the room. When it detects an extended silence, it then fires off a sound clip using a SparkFun audio breakout board. The questions vary from plain to politically sensitive, so there’s a good chance you could get some spicy conversation as a result. Any talking device runs a risk of being more annoying than helpful, and there’s certainly a risk that Chatty Coaster could fall into this category. Choosing the right content seems key here.
Overall, while this may not be the ultimate solution to boring company, it could get a laugh or two and serves as a good way to learn how to work with audio on microcontrollers. Video after the break.
Infinity mirrors have been gaining in popularity recently, thanks in no small part to the availability of low-cost RGB LED strips to line them with. Generally such pieces are limited to wall art, or the occasional table build, which is what makes these infinity mirror drink coasters from [MnMakerMan] so unique.
Built from an ATtiny85 and a WS2812B LED strip nestled into a 3D printed enclosure, these coasters are relatively cheap and easy to assemble should you want to run a few off before the holiday party season. [MnMakerMan] mentions the LEDs can consume a decent amount of energy, so he’s included a module to allow recharging of the internal 3.7 V 1500 mAh battery over USB.
Of course, a couple of PLA pieces and a custom PCB doesn’t make an infinity mirror. To achieve the desired effect, he’s created a stack consisting of a 4″ glass mirror, a 1/8″ thick plexiglass disc, and one-way mirror tint film. The WS2812B strip mounted along the circumference lights up the void between the two surfaces, and produces a respectable sense of depth that can be seen in the video after the break.
Ah, the age-old question: at what temperature does one’s tea need to be for maximum enjoyment? It’s subjective, of course, but subjective in a way that makes everyone else’s opinion demonstrably wrong. What’s worse, the window of opportunity for optimum tea temperature is extremely narrow. What’s a tea drinker to do?
Throw a little technology at the problem, of course, in the form of this Internet of Tea smart coaster. Through careful experimentation, [Benjojo] determined the temperature of his favorite mug when the tea within was just right for drinking and designed a coaster to alert him to that fact. The coaster is 3D-printed and contains an MLX90616 IR temperature sensor looking up at the bottom of the mug. An ESP8266 lives inside the coaster too and watches for the Optimum Tea Window to open, sending an alert via Discord when the time is right. Yes, he admits that a simple blinking LED on the coaster would keep his tea habit metadata from being slurped up by the international tea intelligence community, but he claims he has nothing to hide. Good luck with that.
Whether or not you feel the need to laser cut custom drink coasters, you have to be impressed by the amount of thought that went into Coasty.
They say that justice is blind, and while we can’t promise you anything at your next court date, we can at least say with confidence that we’re not the kind of people who will turn down a good hack just because it’s held together with rubber bands and positive vibes. If it works it works, and it doesn’t matter what it looks like. Having said that, we’re blown away by how incredibly finished this particular project is.
Coasty, designed and built by [Bart Dring] is one of those projects that elevate a hack into something that looks like it could be a commercial product. It takes in a common pulpboard coaster and laser cuts any design you want. It’s just the right size, with just the right components because this is Coasty’s purpose. It has a slot to feed in the coaster, and uses this as one of the axes during the laser cutting process, with the laser’s left to right movement as the other. This method makes for a smaller overall footprint and means you never need to open the protective enclosure for normal operation.
One of the most striking elements of Coasty is how much of the hardware is 3D printed. If it isn’t a motor, smooth rod, or other mechanical component, it’s printed. We’re used to seeing 3D printed parts as brackets or mounts, but rarely do you see an entire chassis printed like this. Not only does it take a serious amount of forethought and design, but the print time itself can be quite prohibitive.
But by designing and printing the majority of Coasty, it really gives it a professional look that would have been harder to achieve if it was a bundle of aluminum extrusions.
The back of Coasty features an exposed PCB “motherboard” with a dizzying array of plug-in boards. Hardware like the stepper drivers, Bluetooth radio, and laser power supply are separate modules for ease of maintenance and development. There’s a few neat hardware features integrated into the motherboard as well, like the IR sensor for detecting the edge of the coaster.
The printed filter is an especially nice touch. Containing a scrap of commercially available carbon cloth intended for home air filters, Coasty is able to cut down on the smoke that is invariably produced when blasting cardboard with a 3W 450nm laser.
What’s better than a cool build? A cool build with valuable advice! Add a few flashy pictures and you have [Martin Raynsford]’s Reuleaux triangle coasters blog post. [Martin Raynsford] wanted to share his advice about the importance of using jigs and we’re sold. He was able to make 100 coasters in a single day and if he’s like us, after number ten, the work gets a little hurried and that is when mistakes are made.
Jig is a broad term when it comes to tooling but essentially, it holds your part in place while you work on it. In this case, a jig was made to hold the coaster pieces while they were glued together. [Martin Raynsford] didn’t need any registration marks on the wood so even the back is clean. If you look closely, the coaster is two parts, the frame and the triangle. Each part is three layers and they cannot separated once the glue dries. If any part doesn’t line up properly, the whole coaster is scrap wood.
Looking to use up some more of his flexible LED strip, Hackaday alum and Tindie writer [Jeremy Cook] tried for a funky accent to his dinner or coffee table: light up coasters.
Using his CNC router to carve out two pieces of translucent plastic to house four 3V CR2032 batteries, four pieces of LED strip, and some wire, [Cook] had created a pressure plate circuit that activated once a drink is set on it. The original layout of the circuit, however, didn’t work, and the space for the LED strips proved to be too small. A quick redesign and some more time with his router resulted in an almost working product. Initially intending to use screws to secure the coaster, hot glue provided the perfect amount of spring once he had thinned out the coaster top to allow it to more easily flex and complete the circuit.
Still looking for that perfect gift? [Joel Witwer] shows us how to make a log coaster set and holder on the cheap. He figures he spent just $5 on the project and from what we can tell that all went to some polyurethane which he used to finish the wood pieces.
It started with an interesting-looking and appropriately sized log which he found on the side of the road. We’re not sure about the ins and outs of drying stock to ensure it won’t crack, but we hope he took that into account. With raw material in hand he headed over to the band saw. The cutting starts by squaring up both ends of the log while cutting it to the final length. He then cut the bottom off of the holder. What was left was set upright so that he could cut the core out of the log. This is the raw material from which each coaster is cut. A spindle sander was used to clean up all of the pieces. The last step before applying finish is to glue the bottom and sides of the holder back together.
[Joel] gave some tips in his Reddit thread. He says you should hold on tight while cutting out the slices for coasters because the round stock will want to spin. He also mentions that some of the slices aren’t as flat as they should have been, something to think about if you’re cutting these for yourself.