Category Archives: Uncategorized

IKEA couch spring repair

About a year ago we purchased and assembled an IKEA sectional sofa for our living space.   A few months later, we notice one of the springs under one of the cushions had sprung loose. And another. By nearly a year … Continue reading

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Scout’s vigil and the beginning of the aftermath

Note: A friend asked if I’d share this FB post more widely.  I refuse to make it global on FB, as it would then invite the inevitable cesspool of comments if it was shared widely.  But feel free to link … Continue reading

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RFID-activated High-Current Power Supply Switch

More details forthcoming. Notes: 2N3904 transistors were replaced by ones with a much lower VCE voltage. The 220uF decoupling capacitor is critical to avoid odd slow powerup oscillations (likely due to relay inductance). Schematic at EasyEDA PDF schematic The enclosure … Continue reading

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Backslash line continuation in code comments

I spent several hours this weekend tracking down a bug that highlights something I never knew about GCC (and the Arduino IDE, which uses GCC). At first I was inclined to blame the limited Arduino IDE, but that in itself … Continue reading

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Arduino Class Sunday July 24 2016

This is a reference post for the Intro Arduino class I am teaching at Decatur Makers on July 24, 2016, from 6pm-9pm.   See the Decatur Makers website for cost and registration info. Getting Started with the Arduino! Low-cost user-friendly microcontrollers … Continue reading

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Tontec 480×320 touchscreen display with Raspberry Pi

Last December, I purchased a Tontec 480×320 touchscreen display for use with a Raspberry Pi.  Complete with case (amazon link).  I bought it along with a Raspberry Pi Model B in order to play with software-defined radio (SDR), motivated by … Continue reading

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Serial communication with a Kenwood TS-570D

I am setting up an amateur radio station at my local maker space, Decatur Makers.  Our transceiver is a Kenwood TS-570D. I have spent a lot of time debugging how to get serial communications working between the Kenwood and a … Continue reading

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KX3 as a (good enough) antenna analyzer

So I am working on a DIY antenna analyzer/impedance meter.  But I need to validate my design against a known antenna analyzer.  I do not own one. But I do — my Elecraft KX3 can calculate SWR.  If you know … Continue reading

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I2C LCD Shield for Arduino – save wires!

The standard character-based display used on many Arduino projects are based on the Hitachi HD44780 chip.  They are available quite inexpensively, as little as $2.59 on eBay shipped from China for a 16×2 display.  Sizes go up to 20×4 (what … Continue reading

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Arduino Class Sunday Dec 13

This is a reference post for the Intro Arduino class I am teaching as part of the Atlanta Radio Club’s 2nd Sunday Tech series.  More info on the series at http://secondsunday.tech. Getting Started with the Arduino! Low-cost user-friendly microcontrollers have changed … Continue reading

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