MicroSD Cards Performance

I read about this “A1” specification on microSD cards: it’s supposed to be “App Performance” and is technically a minimum read and write IOPS. So I got one to find out how much of a difference it makes in an OrangePi Zero running Armbian. Simple test: Prepare an existing microSD card (I-O Data, Class 4,Continue reading “MicroSD Cards Performance”

Reading Temperatures from many DS18B20 via Node.js

The easiest way: harald@opz2:~$ cat /sys/bus/w1/devices/28-*/hwmon/hwmon/temp1_input 21812 22375 23375 The problem is that each sensor takes about 800ms (750ms according to data sheet) conversion time. Making this better and reading them concurrently via Node.js: That’s reading all in parallel (plus about 600ms startup time): harald@opz2:~$ node read-temp.js hwmon0 (28-80000004215e): 23.312 hwmon2 (28-0316884578ff): 21.812 hwmon1 (28-0316884fabff):Continue reading “Reading Temperatures from many DS18B20 via Node.js”

OrangePi Zero + DS18B20

Making my OrangePi Zero useful (again) with updating it to the latest Armbian and connecting a 1-Wire DS18B20 temperature sensor to it. Installing Get a microSD card and install the latest Armbian image for your Zero. Boot and do the usual setup: set root password, create a new user, copy ssh keys etc. Hardware RelatedContinue reading “OrangePi Zero + DS18B20”

Logging via ElasticSearch

The Elastic Stack is a simple way to log “things” into ElasticSearch and make them nicely visible via Kibana. Since ELK can handle logs as well as time series data, I’ll use it for my own logging incl. performance logging. For pure time series data I’d use the TIG stack: Telegraf, InfluxDB and Grafana. InstallingContinue reading “Logging via ElasticSearch”

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