Category: Making

  • The Giving Tree and An Arduino Clock

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    When we bought our house we hired an electrician to install ceiling fans and lights. He worked, worked, and worked. My illusions of electrician’s work dissolved. Their work is a great deal more like laying bricks than solving equations. Oddly, the truth for electricians is also the truth for electronics. Nearly two years after starting,…

  • Wiring an Arduino to a Five-state Guitar Switch

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    I am rebuilding my Arduino-based data collection system. Named the RIMU for some long-forgotten and pointless acronym. My old one used a momentary switch—a button—to change which sensor is displayed on the LCD. It is awful because if the Arduino is busy when you push the switch then nothing happens. I’m fixing it with a…

  • Monsoon

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    In the desert it almost never rains. I know, you know. When I lived in upstate New York, in my foolish youth, I bought a motorcycle in the beginning of April. I was anxious to learn to ride. Too bad, because it rained every day for an entire month. Now I live in New Mexico.…

  • Arduino Flickering Candle

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    Update December 24, 2013: Mokus refined his code so that the distribution is now well-behaved (nearly normal) and the PSD no longer turns up at high frequencies). The plots and post have been updated to reflect this change. He will push code to the same link as available. In my previous post on Candle Flame…

  • Candle Flame Flicker

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    For a project I wanted to make an LED flicker like a candle. I searched for the signal statistics of candle flicker, and I found no data. One student web site suggests that candle flame flicker is a 1/f-type random signal with roll-off of 20 dB per decade increase in frequency. Similar processes are typical…

  • Raspberry Pi Character LCD Degree Symbol

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    It is inevitable that you will want to write the degree symbol to your 16×2 character LCD once you have it wired to the Pi. My son wired it up, and then wanted to display the degree symbol. In the past I have solved that problem for the Arduino using the Adafruit character LCD Arduino…

  • That Noisy Fan–Calibrated Measurement

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    I am working with the freetronics microphone module, which is described as having a sensitivity of “-40 dB typical”—let us assume it is dB (SPL) referenced to 20 micropascals root mean square (rms) at 1 KHz. When I think of an electronic element’s sensitivity, though, I’m thinking volts per micropascal and this is not provided.…

  • Arduino Analog Sample Rate

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    The Arduino Uno is not the ultimate signal processing machine, but it can do some light duty work on burst data. I had trouble finding the maximum sample rate the Uno can support, which is totally critical for most kinds of work. With native prescale Samples, type casts into floats, and stores in an array…

  • Glue on Paper

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    Last summer I assigned my son, then six years old, to do an “inquiry.” Inquiries are guided studies of something, and empirical inquiries are like mini science fair projects. At the time I asked him to pick a topic he selected “how does glue work?” Exploring this at the chemistry level seemed like too big…

  • Does the Bathroom Fan Do Anything?

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    Other than make noise, that is. I built the most recent version of my Arduino-based data logger (the RIMU), and was looking for something to log. I’ve had this question for many, many years—does the bathroom fan actually do anything? It makes noise, deafening Niagara falls thundering noise. The mirror still gets foggy, though, and…