Adding an auto-shutoff to the simplest of drip coffee makers

[Jerry Pommer] and his wife have relied on a percolating coffee pot for years. We have fond memories of camping trips with these things; they make great coffee which tastes even better on a cold morning in the back woods. But a recent package from the stork means that they no longer have time to sit and watch the coffee perk. After several days of boil-overs [Jerry] switched to this very basic drip coffee maker he salvaged from the trash pile. It has one switch that turns it on and off and nothing else. In order to make sure he doesn’t forget to turn it off, he hacked together his own shut-off timer for the device.

His write-up is all back story, but the 34 minute video embedded after the break takes us through the hack itself. We like it that he starts by discussing the different options that he could have chosen. Of course it might have been a microcontroller, or a 555 timer keeping time. But in the end he went with a simple resistor-capacitor timer. The carefully calculated component pair drives a Darlington transistor which keeps a relay closed. When the slowly draining capacitor lets the voltage drop past a certain threshold it also kills the power to the hot plate. In this case it will only stay on for about a half hour.

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Securing your Keurig with RFID

keurig-hacking

[Andrew Robinson] and his co-workers are lucky enough to have a Keurig coffee maker in their office, though they have a hard time keeping track of who owes what to the community coffee fund. Since K-Cups are more expensive than bulk coffee, [Andrew] decided that they needed a better way to log everyone’s drinking habits in order to know who needs to cough up the most cash at the end of the month.

He started by tearing down the Keurig B40, making note of the various PCBs inside while identifying the best way to go about hacking the device. The coffee maker is controlled by a PIC, and rather than try to re-engineer things from the bottom up, he left the core of the machine intact and focused on the control panel instead.

He disconnected all of the unit’s buttons from the control board, routing them through an Arduino before reconnecting them to the machine. This essentially rendered the machine inoperable unless triggered by the Arduino, giving [Andrew] control over the brewing process. He wired in an RFID reader from SparkFun, then got busy coding his security/inventory system. Now, when someone wants coffee, they merely need to swipe their office access card over the machine, which enables the use of its control panel.

As you can see in the video below the system seems to work well. If we were to offer some constructive criticism, we would suggest ditching the laptop and rolling the RFID reading/verification into the Arduino instead – other than that, we think it’s great.

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Web-enabled coffee maker over-complicates your break time

Some think that grinding the beans and filling the coffee maker is part of the coffee-drinking ritual, but [Jamie] isn’t one of them. Instead, he’s been working to make this coffeemaker a web-enabled device. He built it as part of a class project, and has implemented most of what you need to make a cup of Joe automatically.

You can see a small pump attached to the back of the coffee maker. It sucks water from a pitcher (slightly visible to the left of the coffee maker) to fill the reservoir. He experimented with a couple of different water level sensing solutions. His most recent is a PCB with several traces of different length. As those traces are covered by water, a voltage can be read via ADC to establish water level.

He’s using an Arduino and Ethernet shield to add connectivity for the device. The problem is that there aren’t enough ADC pins left on the Arduino to read the water level sensor. Because of this, he added a self-build shield that uses a PIC to do the ADC measurements and push digital data across to the Arduino. A bit complicated, and it doesn’t load the grounds automatically (yet?). But that’s not to say we don’t appreciate complicated coffee hacks.

Can you develop film with coffee and vitamin C?

Are you feeling a little MacGyver-ish and have access to a film camera? Perhaps you want to try developing your pictures using coffee and vitamin C instead of a traditional developing solution. [Danish Puthan Valiyandi] does a great job of walking us through the steps he took, including precise measurements, temperatures, and timings involved in achieving great results. This is probably not for the first-timers, as he does use special equipment associated with traditional developing methods.

The process uses a couple of easily obtainable materials: instant coffee, vitamin C powder, and washing soda (sodium carbonate). Once the roll of film has been exposed, it’s put onto a jig for developing (Danish does this with the lights on to make the video after the break worth watching, but you’ll need to do it in the dark). Once nestled inside of the development container, he mixes up a batch of his diy developer and agitates according to a times schedule. When the development is finished, a chemical fixer–no diy alternative used here–is added to set the film. Dry out the strips and use a scanner to digitize your work. We’re surprised by the quality of the finished product, but we shouldn’t be… he certainly knows what he’s doing.

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Hackaday Links: September 28, 2011

Disposable coffee maker

[Sepehr] didn’t have a coffee maker, and the local coffee shops were all out of joe. He got his fix by making a drip coffee maker out of disposable cups and knives.

Flexible braille display

Thin film technology is being developed to help the visually impaired. This flexible OLED display has embedded muscle cells which create a braille display. [Thanks Aaron]

Printable iPhone tripod mount

Looking to make those iPhone videos a little more stable, and the pictures a little less blurry? Try out this printable tripod mount that [Chris] came up with.

Arduino macro photos

Speaking of photographs, [Daniel] wrote in to share some macro pictures he took of an Arduino. They’re sure to be of interest to those readers who love everything Arduino.

Carpeting a mouse

Add a unique texture to your mouse by covering part of the body with fabric. The lower half of the mouse case above is covered in a carpet-like material [translated]. [Thanks Clicker]

The joy of forums

[John Park] over at Make posted a short story about coming home from vacation to find his espresso machine non-functional. After beating his head against the wall for a while he joined a forum and posted a video. As has happened so many times, another user had seen this exact issue and was able to send him in the right direction.

We realize that this is just a simple capacitor replacement, though we understand his frustration, the original looks perfectly fine. The point here, is that there is usually someone out there on a forum that has experience with whatever your problem is. So don’t waste any time, go join the most awesome forum on the planet and get hacking!

Water-dosing coffee maker augmentation

[Arthur Benemann] has the worst part of making coffee licked. His add-on for a drip coffee maker fills the water to the proper levels for you, saving the drudgery of rinsing out the carafe, carefully filling it to the appropriate level, then pouring it into the machine without getting everything wet. This isn’t limited to a full pot, but is user selectable by the cup based on how many times in a row you hit that red button. One LED gives feedback on the selected mode, then the device uses a washing machine water valve to turn on the tap for the appropriate amount of time. We’re a little bit leery of connecting homebrew hardware to the water pipes in our house. Make sure you’ve done a good job of debugging so that an infinite loop doesn’t flood you out.