Struggling a bit with Rockpool



Apologies if this has already been asked. Me and my 11 year old have been playing with Rockpool a bit. We got it to change the colours on the rainbow based on which button we pressed, and that made sense. We’re now trying to get it to display a different colour based on the temperature, but can’t quite figure out how that’s supposed to work. We put in “less than” under conditions, and that forks off another set of inputs. I can’t work out how I’d put a value in at this point? I just seem to get the same list of inputs. I can’t use a variable as these are just a bunch of colours.

Am I missing something here? Any clues?

BTW, ** great project ** and perfect for someone like me who can use a soldering iron a bit but tends to melt things and is super fuzzy when it comes to what resistor to use, etc.

Many thanks!



I share your confusion! A Rockpool walk-through would be very handy. Some of it is very intuitive, but some of it is bewildering if, like me, you’re completely new to it and don’t know what it can do. Have you had a go at this? - doesn’t answer your question, though!


There are a lot of clever data flow possibilities in Rockpool, but indeed setting thresholds is rather convoluted currently, mostly due to the relative lack of granularity, and the range of values you get out of the modules in a ‘typical’ environment.

… what I mean by that is that the data flow required for a trigger will be wildly different depending on whether you use a temp reading or a light reading.

Still, I guess what you are looking for here will be using the ‘%’ as a comparative value to the Input from weather, possibly with some converters along the way.


I am unforunately a bit dissapointed with Rockpool. Mainly because I feel it reacts slow when I click things.

I’m using an RPi2 and the default web browser, is there anything to try to make it react faster?


Hi, Use a PC instead of the browser on the Pi and you’ll find it’s MUCH faster. If you don’t know the IP address of your Pi you can fire up a terminal and type “ip a” and grab that IP address. Put that into your browser along the lines of :-

Hope that makes sense, if not I can give you step-by-step instructions.


Thanks. It’s a workaround, but unfortunately not a very convenient one for me.

Back, to your original post…

I think it can be done using ‘+’ and the slider/dial to create an input threshold at 500 which will output to one of the three colours.

(Hopefully it makes sense?)


If the temperature passes the limit you set with the dial, the led goes red.

381 is less than 386 so output is 0, if it gets a bit hotter (over 386), output is 1000 --> led turns red


Work is still in progress, but the latest update should make it feel more responsive on Pi 2 by dispensing with some unnecessarily overzealous redrawing.

The whole system is receiving something of a turbo-boost.


Thank you Phil.

Will there be an official announcement for people to go ahead and upgrade?

Also, three targeted bits of feedback:

  1. If you add one input (say for the dial) and you start going up and down, you get a smooth transition between the 0 and 1000 values. However, if you add a second input for the same module, the transition is not smooth at all. (I’ll use this as a test scenario for the next version :-) )

  2. is there a way to “branch” the same one input to multiple outputs in one “line”? (In the same way that I have “branched” multiple inputs to the same output in one “line”.
    (is is called a “line” or something else?)



We call the “lines” in Rockpool, “Rules” or “Flows” - I like the name “Flows” better since it’s a lot less jarring. Line is fine, too, I know what you’re talking about.

At the moment the only way to branch a flow is to output it into a variable, and then use that variable as an input on subsequent lines. There are a couple of reasons why we went this route:

  • It gets visually confusing really quickly
  • It’s not necessary in many cases since you can just re-use the same input

If you want to try the absolutely bleeding-edge software you can find it here:

Rockpool on the Raspberry Pi 2 will always be slower than running it on a desktop, but we’re eager to make it at least usable. Epiphany browser isn’t the most forgiving of targets, either.