Introducing the osPID

About 5 months ago I sent an out-of-the-blue email to RocketScream electronics asking if they wanted to help me build an open source PID controller. It’s been far more challenging than I expected, but today I get to announce the release of my first open source hardware project: the osPID!

(pause for applause)

The goal was to make an open equivalent to the PID controllers you can currently buy. To do this we combined the Arduino, my PID library, some open-source auto-tune code, and RocketScream’s Reflow Oven Controller Shield.

In some areas we fell short: The case, for example, isn’t nema rated. If this thing becomes popular however, there’s no reason we couldn’t fix that.

In some areas we hit our mark: form factor, interchangable I/O cards, Autotune, onboard user interface.

…And in some cases we hit out of the park: It has a java trending/configuration Application, and it costs… wait for it… $85.

I’m really proud of the work we’ve done, and there’s more to come. Let me leave you with some videos I created to help introduce this release.




For more information check out the (slightly rough) website we’ve created at


flattr this!

Tags: ,

15 Responses to “Introducing the osPID”

  1. Jean-François Théorêt says:

    This is fantastic!! Auto-tune to boot!?!

    As an automation student (and former programmer), this will be an invaluable tool for learning.

    Thanks for all your efforts (and your fantastic description of the PID mechanism).

    I will pick one (maybe two??) when they are available.

    Any idea when the firmware and diagrams will be available for download?

  2. Brett says:

    Glad you like it! The firmware and schematics should be up within the next week or two. Everything will be posted here

  3. This is awesome. I pay $600 for Honeywell controllers for the lab I run. While I wouldn’t use this in a production setting (and I don’t think that’s what you’re shooting for), this would be fantastic for a pilot lab/R&D setting. Everytime I’ve used an industrial controller, I always think, “Man, I wish I could do xxx or yyy, but the controller isn’t set up to do that or I have to buy a separate model.” With something like this, I could customize it on the fly depending on the test I’m running.

    Well done!

  4. Brett says:

    While I wouldn’t use this in a production setting (and I don’t think that’s what you’re shooting for)

    as it currently stands, definitely not. We did think about production when designing the boards though. The firmware needs to be completely proven before I would even consider making a production-ready version however.

  5. Adam says:

    This is great! I’ve been using your PID library with the Smartec UTI for the RTD sensing in a massively over engineered sous vide controller.

    I’ll neaten up the firmware and release it, as it might be useful for those wanting to use Pt100 etc. instead of k-type. I’m guessing that’s throwback from the RS re-flow oven controller? I think that uses the MAX31855 too.

    The autotune function is awesome. Congrats on a great project.

  6. David says:

    Good job. I would like to jump in but the part that left me flat was a review someone made on 4 ovens that won’t work. How about the actual name and model number of one that works? Regards.

  7. Brian Doom says:

    The osPID looks very exciting!

    However there’s a piece I’m not quite getting: what do the components that you attach to the inputs and outputs look like? Is it a naked heating element you attach to the relay? What does the input sensor look like?

    Can you maybe post some pictures and description of a simple example?


  8. zippys123 says:

    Hi brett

    check this just my idea
    it would be very helpfull for beginers

  9. Brett says:

    @David, I’m not sure which review you’re talking about. as long as the oven draws < 10A you should be able to quite-safely control it using the osPID. beyond that and you're probably going to need an external Solid-State Relay

  10. Brett says:

    @zippys that looks great! we’re almost there. The firmware is essentially already created, as the osPID is an expansion of the Reflow Oven Controller Shield. Plans to incorporate this functionality are in the works.

    The integrated plug would be a bit trickier. the goal with the osPID was to replicate the 1/16 DIN form factor. this doesn’t really lend itself to a plug. there was talk briefly about having a powertail-style card, with cords sticking out the back. we dropped this idea, but maybe we should take another look.

  11. David says:

    Have the relays on the output card been tested yet? It seems like that could be quite a job for the relays if they are switching many times a second or do I have this wrong? I could figure out how to connect a ssr like your example elsewhere but does it need some kind of special cooling effort? And finally, will any software that runs on the osPid also run on the Reflow Oven Controller Shield? Thanks for you time. I am going to buy the shield or the osPid.

  12. Brett says:

    @David, the relay has had normal use during the development process without any overheating issues. one of the parameters in the firmware is the PWM window size. by default this is 5 seconds (user changeable). so, the relay is rated for 10 million cycles, at ~2 cycles every 5 sec… it should last for a while. As far as using an SSR, the manufacturer datasheet will tell you the cooling requirements. this will depend on the rating of the SSR and the load it’s attached to.

    the osPID and reflow shield firmware are similar but incompatible, due to the different hardware configurations.

  13. David says:

    Thanks for your very detailed answer.I can see you guys are quite busy and appreciate your answer.

  14. Carlito says:

    Hello Brett,
    This looks fantastic, thankyou for all your hard work, will the other output boards support 0-5v, 0-10v, 4-20ma etc? and can the pid library do ramp soak? autotune on ramp soak would be cool too. keep up the good work. I want one…where do I send my money?

  15. Brett says:

    @Carlito you can pre-order an ospid here:

    we are working on an analog output card that will support some, if not all, of those output formats.

    and yes. ramp-soak isn’t a problem for the pid library. just need to update to UI to allow the user to specify.

Leave a Reply