Archive for the 'Raspberry Pi' Category

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 @ https://Mikronauts.com

(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

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:

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

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 @ https://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

Saturday, 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.

https://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)

Related Links:

Raspberry Pi 2 USB hard drive and adapter tests article posted

Thursday, February 26th, 2015

I test two SSD’s, two hdd’s, and four USB2&3 adapters in order to find out how USB drives perform with an Raspberry Pi 2!

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

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I was pleasantly surprised with the test results. Click on the link below for the tests, results, and analysis.

Raspberry Pi 2 USB hard drive and adapter tests

Article Index

  1. Introduction, Test Equipment, Software Setup, Benchmarks, hdparm
  2. dd Read, dd Write, dd Copy, Conclusion