When it comes to logging some data over a long period of time, RRDtool is a convenient solution. Creating and updating the RRD database is simple, graphing is fairly easy as well. To make the graphs available over the web, I chose to install the lighttpd web server.
In this tutorial I’ll show you how to acquire analog data with the BeagleBone Black using the ADS1248 analog-to-digital converter IC. Although the BeagleBone has an onboard 8-channel 12 bit ADC, you might need either more channels or a better resolution. The ADS1248 has 4 differential/7 single-ended inputs and a resolution of 24 bits. Furthemore, the ADS1248 has a built-in current source which can be multiplexed to an analog input or a dedicated pin making a ratiometric resistance measurement pretty straightforward (however, in this introductory post I will not make use of this).