Goldilocks Beverage Coaster Tells You When It’s Just Right

If you ask us, morning is the only excuse we need for a hot caffeinated beverage — weather be damned. Wherever [gokux] is, they may be experiencing actual winter this year, given that they are out there getting cozy with a hot cup of what-have-you. But how do they know it’s at the right temperature for drinking? Enter the temperature-monitoring smart coaster.

At the heart of this build is a GY-906 infrared temperature sensor, which senses the warmth (or lack thereof) and displays the degrees on a small OLED screen thanks to a Seeed Xiao SAMD21. To make things simple, there is also an ideogram that corresponds to the current temperature — snowflake for too cold, danger sign for too hot, and thumbs up for that just-right range. Although this coaster is mostly 3D-printed, the mug sits on a slotted piece of aluminium that is removable for easy cleaning. This would be a good-looking and useful addition to any desk.

This is isn’t the first temperature-indicating beverage coaster we’ve seen. The most recent one ultimately used a probe, which is likely about as accurate (and messy) as you can get with these things.

Beverage Coaster Indicates Ideal Drinking Temperature

When temperatures plummet, there’s nothing like a hot beverage to keep you warmed up inside. [Palingenesis] aka [Tim] sure does fancy a nice cuppa, but only within a certain temperature range is it ideal to drink. In an attempt to signal when the time is just right, he created various iterations of a hot beverage coaster.

To be clear, this is a plywood sandwich that does not keep the beverage warm, though that would be an interesting addition to the project. Rather, it indicates when the beverage’s temperature is just right using LEDs. When it’s too hot, the red LEDs are lit. The green LEDs flash while it’s just right, and once [Tim]’s tea has gone cold, the blue LEDs take center stage.

The brains of the operation is an STM8S103F module, aka the Blue Pill, which is paired with a DS18B20 temperature sensor. [Tim]’s original coaster has one in a TO-92 package embedded in the top layer, but ultimately he went with the probe version as it reads a truer temperature by virtue of being directly in the liquid. Be sure to check out the video after the break which covers planning the original version.

If you do want to keep you drink warm, here’s an ESP8266-based solution. If you’re more into looks, check out this blinkencoaster.

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Memorialize Your Favorite Chips In Slate

There’s no point in denying it — if you’re a regular reader of Hackaday, you’ve almost certainly got a favorite chip. Some in the audience yearn for the simpler days of the 6502, while others spend their days hacking on modern microcontrollers like the ESP32 or RP2040. There are even some of you out there still reaching for the classic 555. Whatever your silicon poison, there’s a good chance the Macrochips project from [Jason Coon] has supersized it for you.

The original slate RP2040

The idea is simple: get a standard 100 mm x 100 mm (4″ x 4″) slate coaster, throw it in your laser engraver of choice, and zap it with a replica of a chip’s label. The laser turns the slate a light gray, which, when contrasted with the natural color of the slate, makes for a fairly close approximation of what the real thing looks like. To date, [Jason] has given more than 140 classic and modern chips the slate treatment. Though he’s only provided the SVGs for a handful of them, we’re pretty sure anyone with a laser at home will have the requisite skills to pull this off without any outside assistance.

The page credits a post from [arturo182] for the idea (Nitter), which pointed out a slate RP2040 hiding out on the corner of [Graham Sanderson]’s desk back in 2021. We just became aware of the trend when [Jason] posted his freshly engraved RP1 on Mastodon in honor of the release of the Raspberry Pi 5.

3D-Printed Woven Coasters Save Tabletops In Style

When regular people think of 3D printing, they likely imagine semi-newfangled objects like twisty vases and useless trinkets. But there is so much more to 3D printing, as [andrei.erdei]’s printed, woven coasters demonstrate.

The design is based on the stake and strand basket weaving technique, which uses rigid strips called stakes in one direction and thinner strips called strands in the other. Since the flexibility of PLA is questionable, [andrei] printed the stakes already bent in a square wave pattern that accommodates the strands fairly easily. To tie the coasters together and make them look more polished and commercial, [andrei] designed a holder as well.

The awesome thing about this technique is that you can do so much with it, like varying the stakes’ widths or making them diagonal instead of square. [andrei] designed these in Tinkercad using Codeblocks; of course, they are open source. Be sure to check out the assembly video after the break.

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ESP8266 Coaster Keeps Your Drink Warm

Looking for the perfect winter desk accessory? [Wq] has created a beautiful coaster made out of PCBs  that can keep your drink warm with an internal heater. (Chinese).

An ESP8266 sits as the main controller, with an additional MQTT control option, where the whole unit is powered over a USB-C connection. On board PCB traces, in the shape of a Hilbert curve, create the heating element used to heat beverages placed on the coaster, where [Wq] reports a measured resistance of the PCB trace network at 1.2 ohms. [Wq] writes that an AON6324 MOSFET replaces the D4184 that was previously being used, but might need some testing to get working properly. There are two capacitive touch sensors which has a TTP223E capacitive touch controller attached to detect input, with a multi-colored FM-3528 RGB LED for user feedback.

We love the artistry that went into building the coaster. For adventurous hackers wanting to build their own, the bill of materials (BOM), source code and board files are all available. We’ve seen everything from coasters and to PCB reflow boards, so it’s nice to see experimentation with a combination of these ideas.

laser cut acrylic coaster with rgb leds inside

Your Mug Will Like This Glowy Coaster

[Charlyn] wanted to highlight their friends beautiful mug collection, so the Glowy Coaster was born.

The coaster is made up of six layers of laser cut acrylic. The top and bottom layer are cut out of clear acrylic, providing a flat surface for the coaster. A top pattern layer made of pearl acrylic has a thin piece of vellum put underneath it to provide diffusion for the LED strip sandwiched inside. The middle layers are made of peach acrylic and have their centers hollowed out to provide room for the electronics inside. The top pearl acrylic layer gives the coaster, as [Charlyn] writes, a “subtle touch of elegance”. The coaster itself is screwed together by an M3 screw at each point of the hexagon that feed through to heat-set inserts.

inside of glowy coaster with electronics exposed

The electronics consist of a short NeoPixel strip, cut to include 12 LEDs pointed in towards the center of the coaster. The LEDs are driven by a Trinket M0 microcontroller with a LiPo “backpack” to provide power, attachment points for the exposed power switch and recharging capability to the 110 mAh 3.7 V battery. The code is a slightly modified NeoPixel “rainbow” wheel loop (source available as a gist). The design files are available through Thingiverse.

Creations like these highlight how much care and work goes into a project with minimal beauty, where decisions, like the opacity and thickness of the acrylic or countersinking the M3 screws, can have huge consequences for the overall aesthetic. [Charlyn] has an attention to detail that brings an extra touch of professionalism and polish to the project.

Coasters are a favorite for laser cutting and we’ve covered many different types, including
coaster bots, coaster engravers and even a color changing, drink sensing coasters.

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Chatty Coaster Agitates, In A Friendly Way

Awkward silences can be highly uncomfortable. Thankfully, they’re a problem that can be solved by technology. Chatty Coaster aims to do just this, detecting pauses in conversation and interjecting with helpful questions to move things along.

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.

We’ll admit, when we were reading this one, we thought we had déjà vu. But this one’s a lot less blamey.

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