Failure modes

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[ Date | 2020-04-30 22:32 -0400 ]
[ Mod. | 2021-10-15 11:48 -0400 ]

I have a small bunch of little network-connected projects at home. They were all fun to set up, but having software and hardware in "production" means handling failures in a way or another. One way is to tolerate flakiness, when bearable, another is to increase robustness.

Network usage bargraph

Setup: Adafruit 24-segment bi-color bargraph display, I²C on Raspberry Pi, display-side REST server a simple Python program waiting for numbers getting pushed to it by machine that has network interface to monitor. Number-pushing service is handled by supervisord.

Failure modes:

I discarded the device after perhaps four years of use, because the LEDs had become dim by then, and replacing it did not seem worth the price of more than USD10 when larger, 32x8 matrix displays are readily available for about CAD10 all-included.

Hygrometer & thermometer

Setup: ESP8266, DHT22 temperature and humidity sensor, optional I²C OLED display.

Failure modes:

"Smart" light scheduling

Setup: off-the-shelf smart plugs and smart switches, cron jobs on a local machine.

Failure modes:

Light switch repeater

Setup: ESP8266, relay module controlled by separate power supply, off-the-shelf smart plug.

Failure modes:

Motion detector

Setup: ESP8266, PIR motion sensor.

Failure modes:

ESP8266-based clock

This has worked fine for months, requiring no maintenance; the only glitch:


ESP8266-based Kodi time remaining display

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