Author Archives: andy


Modern microelectronics assembly requires clockmaker or robotic precission; sub-millimeter discrete components or pinout of integrated-circuits is nothing unusual. Building such highly integration devices from scratch at home is a virtually impossible, sometimes though fixing them with entry-level tools is still … Continue reading

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Water Level Station – rain gauge

Measuring water level is fundamental goal of WLS experiment, hence its code-name (Water Level Station). Early summer 2014 hardware and software system had enough base services to make addition of entry-level pluviometer easy. Prior to PCB redesing for chinese factory I … Continue reading

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Visiting Jordan three years ago I was thrilled by the outstanding Dead Sea. Choosing seaside I had no time for Petra. Once I was requested to get there again I instantly knew where to go this time. Attracted by ancient city with … Continue reading

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Power cycling slave on I2C bus

With the advent of 2nd revision of WLS experimental hardware I got nasty system freezes on ported firmware. As they happened always close to power cycling of probe section I suspected new ADC chip using I2C bus. Past experience with I2C … Continue reading

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SIM900A fixed for Europe

So you got SIM900A, cheaper version of SIM900 with the same pinout/functions and 2-band instead of 4-band GSM radio, just to stumble on logging to network. While its great for Asian GSM infrastructure in different places in the world you … Continue reading

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3D printing at home

These days turning imagination into reality at home is more real than ever. RepRap movement made fused deposition modeling technology affordable. Turning a figurine or mathematical object into physical object is exciting and funny and using 3D printer to fabricate … Continue reading

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PCB from Chinese factory

Working prototype device made of modular PCBs let me go for the next step. Learning the process of professional PCB production in factory and making short series to scale out number of devices in the field. I had to get … Continue reading

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Water Level Logger – insufficient RAM

For prototype I estimated that 128kB or flash would suffice and I was right; firmware took 75kB even though fatten up by embedded strings used across the code for tracing. On the other hand 4kB RAM of Atmega128 turned to … Continue reading

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Powerslide Metro 2011 vs 2013

When I found inner part of liner torn in many places it was time to look for new skates. Powerslide Metropolis 2011 was good pair of boots already proven in urban stroll in dozen places on four continents. Getting new … Continue reading

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Water Level Logger – voltage level conversion

Digital subsystems with different supply voltages have to align their logical states if they want to talk to each other. It can be done with variety of discreet components as well as dedicated integrated circuits. It is simple task these … Continue reading

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