Author: iopadmin

  • Candle Flame Flicker

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    iopadmin
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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…

  • Pens for the Backs of Photographs, More Ink

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    I tested three new writing media for the backs of photographs. I recently went through some 2 or 3 year old pictures I had marked with Higgins Black Magic. In exactly one case I found one photo that had picked up pen marks from another. I do not know if I put them together while…

  • Hot-Smoked Salmon

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    iopadmin
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    This afternoon I made hot-smoked salmon in my father’s MasterBilt smoker. The Web did not provide me with good resources on smoking salmon in a MasterBilt. Or rather, it provided many different and vague recipes. My result was excellent but not perfect. This article details exactly what I did and exactly what I plan to…

  • Barbecued Ribs and Smoke Metrology

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    I made smoked ribs yesterday and tested out a new measurement system based on an Arduino, data logger shield, and a Sharp GP2Y1010 dust measurement unit. I didn’t have a long enough cable to get the smoke measurement unit inside the smoker, so I put it in my own contained pod above the smoker. By…

  • Raspberry Pi Character LCD Degree Symbol

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    iopadmin
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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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    iopadmin
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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…

  • I Don’t Tell You How to Do Your Job

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    iopadmin
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    This article begins with a story from my life, my fatherhood, about the time I was most afraid. The story ends happily with the birth of a healthy baby girl. The article, on the other hand, ends with an analysis showing how medical habit increased the threat to my daughter’s life by a factor of…

  • Does the Bathroom Fan Do Anything?

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    iopadmin
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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…