Internet Of Smells: Giving A Machine The Job Of Sniffing Out Spoiled Food

Has the food in your pantry turned? Sometimes it’s the sickening smell of rot that tells you there’s something amiss. But is there a way to catch this before it makes life unpleasant? If only there were machines that could smell spoiled food before it stinks up the whole place.

In early May, I was lucky enough to attend the fourth FabLab Asia Network Conference (Fan4). The theme of their event this year was ‘Co-Create a Better World’. One of the major features of the conference was that there were a number of projects featured, often from rural areas, that were requesting assistance throughout the course of the conference.

Overall there were many bright people tackling difficult problems with limited resources. This is how I met [Yogesh Kulkarni] who runs a FabLab in Pabal, a farming community not far from Pune, India. [Yogesh] has also appeared on TED Talks (video here). He explained to me that in his area, vendors sell milk-based desserts. These are not exactly refrigerated, and sometimes people become ill from eating them. It would be nice if there was a way for the vendors to avoid selling the occasional harmful product.

I’ve had similar concerns with food safety in my area (Vietnam), and while it has been fine nearly all of the time, a few years ago I nearly died from a preventable food-borne illness. I had sufficient motivation to do a little research.

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Accurate Coffee Billing Through Reverse Engineering

If you’ve ever worked in a stingy office, you’ve become familiar with the communal coffee maker that runs on some variant of the honor system. There’s bits of paper, a coin jar shabbily sealed with sticky tape, and the routine note every six months telling people off for not paying for their daily brew. It all gets a bit much. Thankfully, if you work with [Fabian], it’s no longer a problem (PDF link).

The project forms the basis for [Fabian]’s thesis, in which a DeLonghi coffee maker is reverse engineered. This is undertaken with the explicit goal of properly metering the amount of consumables (coffee beans) used per beverage, to more fairly charge users depending on their brew of choice. This involves breaking down and understanding the coffee maker’s internal communications, as well as implementing a system to record and handle billing. For reasons of simplicity, [Fabian] decided that this should be handled using his colleague’s existing computer accounts. Easy!

It’s a highly academic approach to what we’re sure was a very stimulating project with lots of delicious aromas. Coffee’s a popular topic among hackers, that’s for sure – check out this roaster to take your game to the next level.

 

Serial Connection Over Audio: Arduino Can Listen To UART

We’ve all been there: after assessing a problem and thinking about a solution, we immediately rush to pursue the first that comes to mind, only to later find that there was a vastly simpler alternative. Thankfully, developing an obscure solution, though sometimes frustrating at the time, does tend to make a good Hackaday post. This time it was [David Wehr] and AudioSerial: a simple way of outputting raw serial data over the audio port of an Android phone. Though [David] could have easily used USB OTG for this project, many microcontrollers don’t have the USB-to-TTL capabilities of his Arduino – so this wasn’t entirely in vain.

At first, it seemed like a simple task: any respectable phone’s DAC should have a sample rate of at least 44.1kHz. [David] used Oboe, a high performance C++ library for Android audio apps, to create the required waveform. The 8-bit data chunks he sent can only make up 256 unique messages, so he pre-generated them. However, the DAC tried to be clever and do some interpolation with the signal – great for audio, not so much for digital waveforms. You can see the warped signal in blue compared to what it should be in orange. To fix this, an op-amp comparator was used to clean up the signal, as well as boosting it to the required voltage.

Prefer your Arduino connections wireless? Check out this smartphone-controlled periodic table of elements, or this wireless robotic hand.

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