Board Farm

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Here is some information about board farms.


At the Embedded Linux Conference Europe 2017 Andrew Murray held a BoF session titled Farming Together. The purpose of this BoF was to bring together people that are actively working on board farms to create a community, to knowledge share and to start a collaborative effort.

Add your name and contact information if you would like to be notified when an e-mail list is created, or are generally interested in this topic:

  • Andrew Murray - <amurray (at)> *
  • Tim Bird - <tim.bird (at)> *
  • Robert Schwebel <r.schwebel (at)> *
  • Arnout Vandecappelle - <arnout at mind dot be> -- doesn't have a board farm but is interested
  • Mirza Krak - <mirza.krak (at)> *
  • Alan Bennett - <alan (at)>
  • Geert Uytterhoeven - <geert (at)> *
  • Andrea Scian - <andrea.scian (at)>
  • Kieran Bingham - <kbingham (at)> *
  • Jan Lübbe - <j.luebbe (at)> *
  • Marco Cavallini - <m.cavallini (at)>
  • Kevin Hilman - <khilman (at)>
  • Bill Mills - <wmills (at)>
  • Tom Gall - <tom.gall (at)>
  • Stephano Cetola - <stephano.cetola (at)>
  • Mike Holmes - <mike.holmes (at)>
  • Matteo Vit - <matteo.vit (at)>
  • Attie Grande - <attie.grande (at)>
  • Roland Hieber <r <dot> hieber <at> pengutronix <dot> de>
  • Tim Orling <ticotimo (at) gmail (dot) com>
  • Ryan Arnold <ryan <dot> arnold <at> linaro <dot> org>
  • Behan Webster <behanw (at) converseincode (dot) com> *
  • Michal Simek <monstr (at) monstr (dot) eu>
  • Krzysztof Kozlowski <krzk (at) kernel (dot) org>
  • Jagan Teki <jagan (at) openedev (dot) com>
  • Heiko Schocher <hs (at) denx (dot) de>
  • Khiem Nguyen <khiem.nguyen.xt (at)>
  • Amit Kucheria <amit.kucheria (at)>
  • Harish Bansal <harish.bansal (at)>
  • Chris Paterson <chris.paterson2 (at)>
* = have seen this person on the e-mail list, or already subscribed.

Mailing list

Discussions on this topic have started at on the "Automated Testing" mailing list of the Yocto Project

Next meeting

To be determined.

Maybe at Plumbers 2018, Connect, or ELCE 2018

See Automated Testing Summit



If you know of a presentation on this topic, please add it below:

  • "Test Standards - Can Fuego, Lava and others agree?" by Tim Bird at Linaro Connect SFO 2017
    • description: Tim proposes several areas of standardization collaboration between different Linux test initiatives
    • Slides and Video
  • "Herd Your Boards, Become a Farmer" by Geert Uytterhoeven at ELCE2016
  • "Automation beyond Testing and Embedded System Validation" by Jan Luebbe (Pengutronix) at ELCE2017
  • Introduction to
  • Piece of cake - testing remote embedded devices made easy with MuxPi by Paweł Wieczorek at FOSDEM 2018

Best Practices


Misc / Tools


SD muxers

Kevin Hilman mentioned (at ELCE 2017) wifi SDCards as a way to handle the SD mux problem. Was he referring to something like these?

power control


Here is some information from a discussion in October 2022 about a simple relay used as part of board bootup process:

Shelly relays

Cliff Brake: I've used the Shelly relays to do simple automation projects here (cycle power to boards under test, etc): See

They are low cost, and are very open and have documented REST, MQTT, etc APIs, so I think it would be pretty easy to trigger one of these from a script using curl or something ...

USB relays

Andrew Murray: We often use USB relays (less than £10) - for example this one: - they're typically controlled via a very simple hidraw interface. Applications are available for controlling them (e.g.

However that particular brand appears to have been removed from Amazon - though I've noticed this one which looks like it would be suitable -

These are all slightly overkill as these relays can switch mains voltage and currents, however they are cheap. It is possible to buy solid state relays for lower voltages, but I haven't found a cheap board with one on.

Slightly related, has a lot of useful boards - for example their "USB Switch and Multiplexer" - this appears to be sourced from which also has lots of other goodies.

Michal Sojka: If you can use USB, I'd recommend cheap USB relays found on Ebay, e.g. I use to control them. Over the years, I had about 20 boards controlled with these relays and it always worked well. One such board can be seen at

Bill Mills: If I only need a couple relays I use these: (NOYITO 2-Channel Micro USB Relay Module USB Smart Control Switch USB Intelligent Control Switch)

  • Available from Amazon with free one day shipping. $15
  • USB bus powered with a micro USB connector (I hate full sized B).
  • Uses a simple serial port based protocol
  * The FTDI GPIO or HID ones are a PITA IMHO
  • Works with anything, Linux PC or a BBB or RPI etc.

gpio relays

Heiko Schocher: If you already have a hw and only need a "gpio relay" ... I use for example:

around 9 euros each or

Works fine for me to switch for example bootmode on imx6 based boards...

And may this is also interesting, if you need a cheap standalone solution

You will find similiar on amazon to ... you can run Tasmota on it

custom electronics

Geert Uytterhoeven: There are two approaches to handling this:

 1. Automatically trigger a button press after power is applied.
    I.e. you want to generate a delayed pulse of N ms that happens
    M ns after the power comes up.  I guess than can be implemented
    with a 555 timer. This will require some (fun? ;-) elektronics
    work, though.  See [1]

 2. Control the button remotely.
    As several people, this can be handled through a relay, but IMHO
    that's overkill.  As you already have spare pis and bones, all you
    need is a resistor (e.g. 220 or 270 Ohm) and an opto-coupler (e.g.
    HCPL-181), to be driven from 3.3V GPIO.

Personally, I'd go for the second approach, as such a button is typically also used for other purposes (power-off, suspend, wake-up), so you probably want to have full control over it.


USB mega-ports

A few people are using these:

USB switchers

gpio controllers

HDMI testing

unsorted LAVA hardware helpers


Possibly to control various buses (via FPGA).




  • spend money on USB serial adapter cables - cheap adapters sometimes drop connections and are a pain to debug
    • FTDI cables seem to work well.

Farm Survey

Tim Bird is conducting a survey of Farm hardware (DUT controllers). See this page: Board Farm Survey