Archive for March, 2015

Raspberry Pi Data Acquisition & SPI Multiplexing

Saturday, March 21st, 2015

I’ve seen quite a few questions in the forums on how to add more SPI devices … so I decided to write up one of my Raspberry Pi based data acquisition projects.

SPIMux / Analog Data Acquisition @

(click on the image for larger version)

Currently there are 8 channels of 0-4.096V inputs with 1mV resolution, and 16 channels of 0-8.192V channels with 2mV resolution, article has the schematic and Python source.

I used three MCP3208’s, a 74HC138N, precision resistors and a precision voltage reference in order to add 24 channels of analog input to one of my Raspberry Pi’s.

Article Index:

  1. Introduction, Problems: Conversion Error, Number of Channels, Input Voltage Range, Schematic
  2. Software Support, Sample Code, Results, Conclusion

Banana Pi & Pro SATA and USB Hard Drive Tests and experiments

Sunday, March 8th, 2015

Did you even wonder if the SATA port on a Banana Pi, and a Banana Pro makes a difference?

Banana Pi & Banana Pro SATA and USB Hard Drive experiments @

(click on image for larger version)

Is it really that much faster than USB-SATA converters (like the ones needed for the Raspberry Pi)

I decided to find out, comparing an SD card, USB-SATA adapters, and SATA drives on a Banana Pi and a Banana Pro.

There are four drives competing here… a 5400rpm laptop drive, a 7200rpm 3TB desktop drive, a slow SSD and a fast SSD.


OOPS! Corrected URL for last tweet

Monday, March 2nd, 2015

My apologies, sometimes I type too fast.

I’ve fixed the title and link for my latest blog post. The corrected URL is:

Sorry about the double tweet!!!

Raspberry Pi 2 NAS Experiment HOWTO (with benchmarks)

Monday, March 2nd, 2015

How fast can a Raspberry Pi 2 file server be?

I thought I’d measure the performance of a Raspberry Pi 2 SMB server… with the on-board 10/100 Ethernet, and a USB Gigabite adapter.

Raspberry Pi 2 Model B Review @

(click on image for larger version)

There have been so many questions on the forums about using the Raspberry Pi 2 as a server – and some unrealistic hopes of gigabit performance – that I ran more tests than I originally intended to pin down the performance limits.

I welcome your feedback on my forums – or the Raspberry Pi Forums!

Article Index