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Java Developer / Linux Sysadmin. * Android location sharing app - https://graticule.link/ https://graticule.link/ * HN "Who's Hiring?" thread search frontend

Java Developer / Linux Sysadmin. * Android location sharing app - https://graticule.link/ https://graticule.link/ * HN "Who's Hiring?" thread search frontend - https://hnjobs.emilburzo.com/ https://hnjobs.emilburzo.com/ * DIY home monitoring - http://ambient.emilburzo.com/#overview http://ambient.emilburzo.com/#overview * SMS enabler for crippled Nexus 7 2013 LTE tablets - https://play.google.com/store/apps/details?id=com.emilburzo.nexus7sms https://play.google.com/store/apps/details?id=com.emilburzo.... * A webapp for browsing the top 1000 indebted companies from Romania - http://datoriistat.emilburzo.com/top1000 http://datoriistat.emilburzo.com/top1000 (it's in Romanian) * A paragliding exam refresher/quiz (not online yet)

hyperenergy 10y ago
What are you using for monitoring individual rooms?
- emilburzo 10y ago
  Right now I have the following on a breadboard (see [1] for the illustrated version) * ATTiny84 * DHT22 temp/humidity sensor * 433 MHz TX module * 3 x AAA batteries * LED used for signalling (like booting up) Initially I was using an Arduino Nano, but I couldn't optimize it enough so that it can live only on batteries, so I went with the ATTiny which is pretty impressive. My oldest sensor node has been running for over 6 months on the same batteries and it still has some juice left (3.9V currently, it should work until it gets below 3.7V) After I've settled with a final design I'm planning to solder it on a perfboard. The DHT22 sensor accuracy is my only issue left, specifically the humidity measurement part (see [2] for some extensive research by someone smarter than me). Everything is on github[3] but it's pretty messy at the moment (hardcoded and such) because there's never enough time for everything. [1] - https://raw.githubusercontent.com/ambient-monitoring/node/master/node_breadboard.png https://raw.githubusercontent.com/ambient-monitoring/node/ma... [2] - http://www.kandrsmith.org/RJS/Misc/Hygrometers/calib_dht22.html http://www.kandrsmith.org/RJS/Misc/Hygrometers/calib_dht22.h... [3] - https://github.com/ambient-monitoring https://github.com/ambient-monitoring

hyperenergy 10y ago

What are you using for monitoring individual rooms?

emilburzo 10y ago
Right now I have the following on a breadboard (see [1] for the illustrated version) * ATTiny84 * DHT22 temp/humidity sensor * 433 MHz TX module * 3 x AAA batteries * LED used for signalling (like booting up) Initially I was using an Arduino Nano, but I couldn't optimize it enough so that it can live only on batteries, so I went with the ATTiny which is pretty impressive. My oldest sensor node has been running for over 6 months on the same batteries and it still has some juice left (3.9V currently, it should work until it gets below 3.7V) After I've settled with a final design I'm planning to solder it on a perfboard. The DHT22 sensor accuracy is my only issue left, specifically the humidity measurement part (see [2] for some extensive research by someone smarter than me). Everything is on github[3] but it's pretty messy at the moment (hardcoded and such) because there's never enough time for everything. [1] - https://raw.githubusercontent.com/ambient-monitoring/node/master/node_breadboard.png https://raw.githubusercontent.com/ambient-monitoring/node/ma... [2] - http://www.kandrsmith.org/RJS/Misc/Hygrometers/calib_dht22.html http://www.kandrsmith.org/RJS/Misc/Hygrometers/calib_dht22.h... [3] - https://github.com/ambient-monitoring https://github.com/ambient-monitoring