Author Archives: andy

EMI shielding

Posted on 2015/09/01 by andy

Close GSM antenna proximity to bare PCB was troublesome latching microSD. Using most resilient flash cards nearly solved the problem. Extra shielding would help to prepare for worst field conditions like area of weakest GSM signal leading to highest emission and … Continue reading →

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OSX mishandles SSID with @ sign

Posted on 2015/08/01 by andy

Lately at the airport so-called user-friendly Apple operating system  was stubbornly failing to log into WiFi without giving me any clues. Meanwhile Android phone was happily sucking data from the same hotspot. It turned to be an OSX (Yosemite 10.10.4) … Continue reading →

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GSM antenna freezes microSD

Posted on 2015/07/28 by andy

Dealing with RF is tricky part of electronic design, even though I never had significant issues with GSM in my prototypes. Advancing in WLS project however I discovered a nasty issue with micro SD prone to lock up on interference … Continue reading →

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External RAM and lost MCUCSR

Posted on 2015/06/18 by andy

Atmega’s MCUCSR status register gives info about restart reason like regular reset-pin shorted, watchdog initiated reset, or brown-out on low voltage from power supply. Pieces of valuable information for device defect tracking. Reading MCUCSR early in test program was fine, … Continue reading →

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100 articles

Posted on 2015/04/13 by andy

Shortest post ever: 100 articles published right after 4th blog anniversary, 4 most popular articles were viewed 100k times altogether, all articles 400k times (entry page does not count) and I still have no idea why I am doing this … Continue reading →

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Pimp my bus: from 8-bit AVR to 32-bit ARM

Posted on 2015/04/13 by andy

Going to newer architecture is unevitable evolution. ARM series is particularly good choice as knowledge of its core functionality is to large extent portable across manufacturers. While ARM Cortex-M chips are close to 8-bit AVRs in footprint size and price … Continue reading →

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Unf*cking my mac

Posted on 2015/03/25 by andy

Beer flushed thru air vents into Macbook mainboard killed it instantly. F-words came even faster as it was done by someone sitting next to me on the airplane from Germany to USA, a guy who called it an accident, not a … Continue reading →

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Water Level Logger – Firmware over-the-air

Posted on 2015/03/10 by andy

Over time firmware stabilizes but rework never entirely completes, either due to inevitable bugs or further enhancements. Manual firmware update applied to couple stations in the field has relatively low effort and is just dauting task. While number of stations … Continue reading →

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GSM workshop

Posted on 2015/01/27 by andy

Warmed up with HTC smartphone fix among other micro repairs I decided to give a chance and fix two other phones with accidently damaged displays. Both Sony Xperia Z2 and BlackBerry Z10 were given ridiculous cost estimates by authorised service and … Continue reading →

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Water Level Station – field tests

Posted on 2014/12/29 by andy

Solar panel, probe and main unit is part of my balcony landscape for over a year now. This setup is running from many weeks to several months uninterruptedly depending purely on firmware upgrades. Field tests being final proof are needed though … Continue reading →

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