Home Brew Supercapacitor Whipped Up In The Kitchen

[Taavi] has a problem – a wonky alarm clock is causing him to repeatedly miss his chemistry class. His solution? Outfit his clock radio with a supercapacitor, of course! But not just any supercapacitor – a home-brew 400 Farad supercap in a Tic Tac container (YouTube video in Estonian with English subtitles.)

[Taavi] turns out to be quite a resourceful lad with his build. A bit of hardware cloth and some stainless steel from a scouring pad form a support for the porous carbon electrode, made by mixing crushed activated charcoal with epoxy and squeezing them in a field-expedient press. We’ll bet his roommates weren’t too keen with the way he harvested materials for the press from the kitchen table, nor were they likely thrilled with what he did to the coffee grinder, but science isn’t about the “why?”; it’s about the “why not?” Electrodes are sandwiched with a dielectric made from polypropylene shade cloth, squeezed into a Tic Tac container, and filled with drain cleaner for the electrolyte. A quick bit of charging circuitry, and [Taavi] doesn’t have to sweat that tardy slip anymore.

The video is part of a series of 111 chemistry lessons developed by the chemistry faculty of the University of Tartu in Estonia. The list of experiments is impressive, and a lot of the teaser stills show impressively exothermic reactions, like the reduction of lead oxide with aluminum to get metallic lead or what happens when rubidium and water get together. Some of this is serious “do not try this at home” stuff, but there’s no denying the appeal of watching stuff blow up.

As for [Taavi]’s supercap, we’ve seen a few applications for them before, like this hybrid scooter. [Taavi] may also want to earn points for Tic Tac hacks by pairing his supercapacitor with this Tic Tac clock.

[Thanks, Lloyd!]

Tic Tac Clock

tic-tac-clock

Here’s an excuse to eat a bunch of Tic Tac candies: once the container is empty it makes a nice little enclosure for your next project. This particular offering introduces a point-to-point clock project that’s a ton of fun.

[Danny Chouinard] did a lot with very little. You can get the gist of the circuit just by looking at the photos above. it uses a 3×5 Charlieplexed LED display (this is given away by the fact that there’s only a few resistors on the board. A bit difficult to see, but between the resistors and the ATtiny84 there is a clock crystal, and on the back is a little piezo buzzer. The one thing that isn’t completely obvious is the power source. Two AAAA batteries, salvaged from a 9V battery, are able to keep the unit running at an estimated 2 years of moderate use.

The video after the break is worth a look though. It shows the various characters and information that can be flashed on the LED matrix. At first it’s hard to tell that the single user input button is being pressed by [Danny’s] thumb.

If you don’t want to build a clock, there are still plenty of reasons to eat a whole container of these mints. You could replace them with a PIC programmer or a discreet camera.

Continue reading “Tic Tac Clock”

Tic Tac PIC Pack: A Pocket Programmer

Sure, mint tin housings are great. But you have to defend against shorts, and cutting out holes for ports and buttons is dangerous business. [Daniel] prefers plastic, and he tipped us off about a PICKit2 clone that he designed to fit inside of a tic tac box.

Almost all of the components were salvaged except for the microcontroller and the connectors. He wound his own inductor using the ferrite core from a CFL. [Daniel] had to make a few improvisations for this project. He didn’t have a 20MHz crystal, so he used a 12MHz crystal and tweaked the fuse bits after burning the firmware.

To save space on the board, he soldered wires to RESET, VCC, GND, PGD, and PGC to program the firmware and then removed the wires. The only trouble he had with it was more or less easily solved by replacing two transistors.

You may remember that we linked to his USBasp programmer in a mentos container a few months back. We figure [Daniel] must have some pretty fresh breath.