Hackaday Prize Entry: Wirelessly Charged Self-Heating Coffee Mug

Many productive hackers bleed a dark ochre. The prevailing theory among a certain group of commenters is that they’re full of it, but it’s actually a healthy sign of a low blood content in the healthy hacker’s coffee stream. [Bharath] is among those who enjoy the caffeinated bean juice on a daily basis. However, he’d suffer from a terrible condition known as cold coffee. To combat this, he built an app-enabled, wirelessly chargeable, self-heating coffee mug.

We know that most hackers don’t start off planning to build objects with ridiculous feature lists, it just happens. Is there an alternate Murphy’s law for this? Any feature that can be added will? The project started off as some low ohm resistors attached to a rechargeable power bank. A insulated flask with a removable inner stainless steel lining was chosen. The resistors were fixed to the outside with a thermal epoxy.

However, how do we control the resistors? We don’t want to burn through our battery right away (which could end up more literally than one would like), so [Bharath] added a Linkit One microcontroller from Seeed Studio. With all this power at his disposal, it was natural to add Bluetooth, a temperature sensor, and app control to the cup.

After getting it all together, he realized that while the insides were perfectly isolated from the liquids held in the flask under normal use, the hole he’d have to cut to connect to the charging circuit would provide an unacceptable ingress point for water. To combat this he added the wireless charging functionality.

With his flask in hand, we’re sure the mood boost from not having to slog through the dregs of a cold container of coffee will produce a measureable improvement in productivity. Video after the break.

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Hot plate stirrer dissolves support material in 3D printed objects


When you want to print a 3D object you run into problems if there is a part that has nothing below it. The hot, soft filament coming out of the extruder will droop with gravity if not given something to rest on while it hardens. The solution is to use a second material as a support. But then you’ve got to find a way to remove the support structure when the printing is done. That’s where this beauty comes in. It’s a heated stir plate for dissolving PLA.

The PLA is printed using a second extruder head. Once the part is cooled [Petrus] puts it into a heated bath of sodium hydroxide (lye). The solvent will remove the PLA but not harm the ABS. Speaking of ABS, [Petrus] also mentions that this can double as a temperature controlled hot plate for polishing ABS prints using acetone vapor.

There’s all kinds of good stuff inside of this beast so do check out the full plans to learn more. Our favorite part is the stir bar which is a piece of threaded rod and a couple of nuts. To make it safe to submerge in the chemicals he 3D printed a pill-shaped enclosure for it.

[Thanks Matt]

Electric poncho keeps you warm on the go


With the mild winter and spring we have had, it might seem strange to think about ways to keep yourself warm, but there’s no better time than the present to prepare for chilly weather down the line.

In his blog [Berto] was thinking about how to keep warm when things cool off again, and decided that a heated poncho would be great to have on hand. He found a dead simple way to craft his heated poncho, requiring little more than a bit of wiring, some thread and cloth, as well as a pair of scissors.

[Berto] picked up a 12V-powered electric blanked, then proceeded to cut a head-sized slit in the middle of it, avoiding the heating coils. He sewed a bit of cloth around the hole to ensure it didn’t end up ripping over time, then he wired the blanket up to a 12V battery he tucked away in his backpack.

The result is a variable-temp poncho that you can use to keep warm in a variety of situations. [Alan Parekh] from Hacked Gadgets says that he thinks the poncho would be awesome on a full-day snowmobiling trip, and we think he’s right!

Continue reading to see a short video where [Berto] explains how to put one of these heated ponchos together.

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Heated aluminum bed for MakerBot

[Keith] built this aluminum-plate heated build stage for his MakerBot 3D printer. We just saw a different MakerBot heated build stage yesterday that relied on glass as the printing surface. Keith’s design is similar to the aluminum RepRap bed but scaled down for the MakerBot. He had a piece of aluminum machined the to correct dimensions, and perfectly flat to use as the printing surface. The yellow surface is caused by Kapton tape applied to the top of the plate. This heat-resistant covering is perfect to print on, resulting in glossy smooth surfaces that are easy to remove once the printed part has cooled. He’s working on improving his mounting technique to achieve prefect level so that he can print without a raft.

[Keith’s] writeup is phenomenal. He’s sharing knowledge in a way that is useful even if you’re not building the exact same kind of project. Follow his lead with your own write-ups, then let us know once you’ve posted them.

[Thanks Marty]

DIY Heated vest/clothing

[Jared] sent in his experiment in building his own heated vest for motorcycle riding. He used some of the ever so common enamel coated wire and some surplus teflon tape in place of Teflon coated wire. So far he’s been testing things out with a bench power supply, but it seems to be working. Despite my love of building my own stuff, I’d probably just pony up for a commercial product. His site is hosted on his DSL, so I’ve put up a mirror here. (with some tweaks to the thumbnails to make them load faster.)