Piface 2

Hi, I want to be able to control more Outputs and I thought using Piface 2. Before buying it I have a couple of questions:

  1. does it work without any programming from my side (I mean code) ?
  2. any suggestions about a relay board to connect to the outputs and control lights, for example ?

Thanks for your help

Hi Rogerio,

No programming skill is necessary to use the Piface / Piface 2 boards from Cayenne, once the board is added to your Raspberry Pi, you can add it to Cayenne via Add New > Device / Widget > Extensions > GPIO Port in the Cayenne UI.

If the two Relays on that board aren’t enough for you, I’m tagging @HighTech who frequently posts here on this thread, he probably has a custom relay board he can suggest that would satisfy your needs, if you let us know a little more about how many relays you’re looking for, feature requirements, etc.

whatcha controllin’?

H, thank you and let me explain.

I bought a couple of remote relays and I replaced my manual control of the blinds with them. Then I “hacked” the buttons of the remote controls (brown on the photo) to make the blinds go up, down and stop as well as schedule the movements in the morning and afternoon. This alone takes 6 out of the 7 analog ports of the rasp.

I also installed a light sensor which connects to the white remote in the photo which is able to control 3 220V switches. When the illumination in my study goes below a certain value I turn on the light. And the last analog output port is gone.

I want to be able to control more blinds as well as other lightning so what I basically need is a board which allows me to expand my analog ports so as to be able to control anything at low voltage (3.3V) or directly a 220V plug. Here is where the Piface 2 and the relays board come in.

Any comments, ideas or suggestions ?

Thank you and regards


Well, I got the PiFace 2, inserted it, added it, and, in the dashboard I can control On/Off each of the Outputs (I see the LEDs go On/Off). Perfect.

Until now I control directly the GPIO pins but, when I change the state of the GPIO pin, I don not see it reflected in the PiFace. So, and I could not find any documentation on how to map the GPIOs to the PiFace. How do we progam the PiFace ?

Thanks for the help

Hi, is anyone able t o help on this ?


PiFace is connected to the Raspberry Pi using SPI.
On PiFace is MCP23S17 chip (16 INPUT/OUTPUT).

Hi, I am talking about Raspberry B and PiFace Digital 2.

Can you please elaborate a bit more your answer ? As said, I can change the Led status but I cannot use it otherwise.


You have Piface connected to a Raspberry Pi as an extension?

Yes, I connect it to the GPOI bus and, in Cayenne, I put it as an extension. From there I can change the status of the output (I see the LED changing) but I cannot connect it and use any of the outputs the way I am using now, to trigger an output.

When adding a new widget, you can choose whether you want to connect to the GPIO or Piface or more

Yes, I did that but I will retry it this afternoon. As said, from the interface I can switch the Led, meaning that I am arriving to the PiFace. I just cannot associate a PiFace channel to a trigger instead of the GPIO channel.

If I understand correctly, so you do not have any outputs on them?
I am sorry, my English is not good.

I can see all the In + Out columns, I can switch the status of the Outputs but I cannot see how to movean Output I currently have in GPIO to the PiFace. How do I say that this output in no longer in the GPIO but in the PiFace ?

This is what I have

So, how do I map a trigger, on the left side for GPIO, to the PiFace channel ?

I can create a Widget but, when it appears on the dashboard, it says Unreachable.

Should I remove the Widgets that deal with the GPIO ? Could these be messing with the control ?

Try removing one widget, and then replace it with piface widget and refresh the page.

Hi Rogerio,

I’m trying to follow along with you, and I have a PiFace Digital 2 at my desk here (I hope you have the same one). I’m curious what ‘Board Number’ you selected when adding it to Cayenne. When I add mine I’m not able to associate any widgets on it, so trying to figure out what I’m doing wrong.

So that is my caveat that I’m working blind with this response, and I can add more when I get this working :slight_smile:

I believe you should be able to click on the individual widgets on your GPIO list on the left, and it will open a settings dialog where you can change them from the integrated GPIO to the PiFace GPIO. Then you should be able to pick those widgets when building an if/then trigger.

Well, despite the board has the default baser address (0), only if I chose the last PiFace Digital (from top to bottom), I manage to change the output (LED On/Off) so I imagine that the bottom PiFace is address 0. Any other wont change the LED. A way to identify which one is available would be great.

I did what you suggest (change from GPIO to PiFace on the left), it moved to PiFace on the left but did not work, says Unreachable. I did a reboot and, Puf, all the widgests disapperead. Also if I try to create one, most of the times it gives an error and when, finally, it does create and appears in the Dashboard, again, Unreachable.

Also, when I try to add a Widget under Actuators, it returns an error stating Failed to add Sensor but I am clearly under Actuators.

Any ideas ?

Once I can get ahold of someone on our team who has more experience with how we implemented this extension I should have something to offer. It may end up that we have a bug but I’d like to reproduce it before concluding that. I’ll post here as soon as I know more.

Thanks, I appreciate that.