Raspberry Pi Data Acquisition & SPI Multiplexing

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 @ http://Mikronauts.com

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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

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 @ http://Mikronauts.com

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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.

See http://www.mikronauts.com/banana-pi/banana-pi-pro-sata-and-usb-hard-drive-tests/


OOPS! Corrected URL for last tweet

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:

http://www.mikronauts.com/raspberry-pi/raspberry-pi-2-nas-experiment-howto/

Sorry about the double tweet!!!


Raspberry Pi 2 NAS Experiment HOWTO (with benchmarks)

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 @ http://Mikronauts.com

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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

 


Raspberry Pi 2 runs nicely on a SATA hard drive using a USB/SATA enclosure

February 28th, 2015

After testing USB SATA adapter performance on the Raspberry Pi 2 Model B, I decided it would be nice to have a lot more disk space for Raspberry Pi 2 development work for RoboPi and my other projects.

http://Mikronauts.com Raspberry Pi 2 USB hard drive and adapter tests

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I used gdisk to re-partition the 3TB 7200rpm Toshiba SATA drive, making a 200GB ‘usbroot’ partition, and making a ‘usbdrive’ partition for the rest of the drive for files.

It will be interesting to see how it performs as a development box – will the extremely fast seek times of an SD card be more important than the (roughly) twice as fast disk read speed?

The Raspberry Pi 2 is quite capable of being used as a development system, so I’ve decided to make a dedicated RPi2 development box I can ssh and rdp into from anywhere in my network.

So far I can report that the system feels snappier, especially when loading large applications. I will probably do some more tests later.

The output from ‘df’ is also pleasing :)

(Please let me know if y’all would like an article/howto on how to set up such a box)

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