Author Archives: Sean Boyce

Shockingly, DARPA’s Brain Stimulator Might Not be Complete Nonsense

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Where does your mind jump when you hear the mention of electroshock therapy? The use of electrical current to treat various medical conditions has a long and controversial history. Our fascination with the medical applications of electricity have produced everything from the most alarming of patent medicines to life-saving devices like pacemakers and the Automatic External Defibrillator.

The oldest reference I could find is the use of the torpedo fish to allegedly cure headaches, gout, and so on in 43 CE. Incidentally, Torpedo torpedo is an awesome species name.

Much more recently, there has been interest in transcranial direct current …read more

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How Pure is this Cup of Joe? Coffee, Conspiracy, and Citizen Science

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Have you ever thought about coffee purity? It’s more something you’d encounter with prescription or elicit drugs, but coffee is actually a rather valuable commodity. If a seller can make the actual grounds go a bit further by stretching the brew with alternative ingredients there becomes an incentive to cheat.

If this sounds like the stuff rumors are made of, that’s because it is! Here in Ho Chi Minh City there are age-old rumors a coffee syndicate that masterfully passes off adulterated product as pure, high-grade coffee. Rumors are one thing, but the local media started picking up on these …read more

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Review: IoT Data Logging Services with MQTT

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For the last few months, I had been using Sparkfun’s Phant server as a data logger for a small science project. Unfortunately, they’ve had some serious technical issues and have discontinued the service. Phant was good while it lasted: it was easy to use, free, and allowed me to download the data in a CSV format. It shared data with analog.io, which at the time was a good solution for data visualization.

While I could continue using Phant since it is an open-source project and Sparkfun kindly releases the source code for the server on Github, I thought it might …read more

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Coffee, Conspiracy, and Citizen Science: An Introduction to Iodometry

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I take coffee very seriously. It’s probably the most important meal of the day, and apparently the largest overall dietary source of antioxidants in the United States of America. Regardless of whether you believe antioxidants have a health effect (I’m skeptical), that’s interesting!

Unfortunately, industrially roasted and ground coffee is sometimes adulterated with a variety of unwanted ‘other stuff’: corn, soybeans, wheat husks, etc. Across Southeast Asia, there’s a lot of concern over food adulteration and safety in general, as the cost-driven nature of the market pushes a minority of vendors to dishonest business practices. Here in Vietnam, one of …read more

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Manufacturing Your Own Single-Origin Tea

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It’s nice to take a break from hacking together the newest bleeding-edge technology, relax, and enjoy a beverage. It’s no surprise that hacks devoted to beer and coffee roasting are popular. We’ve also seen a few projects helping brew the perfect cup of tea, but none involving the actual production of tea. Today we’re going to take a short recess from modernity and explore this ancient tradition.

Consumption of tea is about equal to all other manufactured beverages, such as coffee and alcohol, combined. It is hands-down the most popular manufactured beverage in the world, and we thought it would …read more

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An Introduction to Solid State Relays

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When we think of relays, we tend to think of those big mechanical things that make a satisfying ‘click’ when activated. As nice as they are for relay-based computers, there are times when you don’t want to deal with noise or the unreliability of moving parts. This is where solid-state relays (SSRs) are worth considering. They switch faster, silently, without bouncing or arcing, last longer, and don’t contain a big inductor.

An SSR consists of two or three standard components packed into a module (you can even build one yourself). The first component is an optocoupler which isolates your control …read more

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The Electronics Markets of Ho Chi Minh City, Vietnam

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When we think about world-famous electronics markets in Asia, usually Shenzhen, Tokyo’s Akihabara, or Shanghai’s Beijing Road come to mind.

There’s another market that I’ve had my eye on for a few years: Nhật Tảo market in Ho Chi Minh City, Vietnam. It might not be as large or accessible as the more well-known markets, but it’s very much worth a visit if you’re in the area. I decided it was time to hop on my red motorbike (red things go faster) and give you a short tour of the central market, as well as some more hobbyist-friendly options.

Overview

…read more

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The Science Behind Lithium Cell Characteristics and Safety

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To describe the constraints on developing consumer battery technology as ‘challenging’ is an enormous understatement. The ideal rechargeable battery has conflicting properties – it has to store large amounts of energy, safely release or absorb large amounts of it on demand, and must be unable to release that energy upon failure. It also has to be cheap, nontoxic, lightweight, and scalable.

As a result, consumer battery technologies represent a compromise between competing goals. Modern rechargeable lithium batteries are no exception, although overall they are a marvel of engineering. Mobile technology would not be anywhere near as good as it is …read more

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Switching: from Relays to Bipolar Junction Transistors

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How many remote controls do you have in your home? Don’t you wish all these things were better integrated somehow, or that you could add remote control functionality to a random device? It’s a common starting point for a project, and a good learning experience for beginners.

A common solution we’ve seen applied is to connect a relay in parallel to all the buttons we want to press. When the relay is triggered, for example by your choice of microcontroller, it gets treated as a button press. While it does work, relays are not really the ideal solution for the …read more

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ESP8266 Adds Slick Touchscreen Controls to a Stretch Limo

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The popularity of the ESP8266 WiFi module has a lot to do with its ability to inexpensively connect to the Internet. However, [hwhardsoft]’s stretch limousine environmental control system explores another use for these modules: a simple way to tie together disparate systems with a common user interface.

On a basic level, the problem is one we’ve all faced: multiple devices with multiple control interfaces create an awkward user experience. Have you ever worked in an office with 6 brands of air conditioner requiring 6 different remotes? Because of its low-cost, support for Wi-Fi, serial, and GPIO, ESP8266 boards are a …read more

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