Explorer pHat intro documentation


#1

Hi, I have just started looking at the Pi Zero with Explorer pHat - got Pixel on it - boots fine with Explorer pHat attached - now I would like to do something with the Explorer pHat - but all the docs are for Explorer Hat/Pro - I don’t have much experience with wiring up circuits and really don’t want to fry my kit on the first attempt - is there any documentation/tutorial for the Explorer pHat?

Thanks,

Mark


#2

I’ve also started to try to hack my way through the Hat documentation and install to see how far I can get but… fatal flaw in the plan - the install requires internet connection - which the Pi zero does not have!


#3

I’ve now tried installing the required libraries by switching the os card to a Pi3 to do the curl and apt-get calls - then switched back to the Pi zero and tried importing explorerhat in python but I just get ‘i2c = SMBus(i2c_bus_id())’ FileNotFoundError No such file or directory :(

Is there any way to set this up without internet connection?


#4

There should be a way to set it up via your Pi 3. The error message you describe suggests that “i2c”, the protocol used to communicate with some of the devices on the pHAT, hasn’t been enabled. This should have happened automagically as part of the install process.

Try navigating into the Raspberry Pi menu, picking “Preferences” and then “Raspberry Pi Configuration”. Click the tab called “Interfaces” and make sure “Enabled” is checked next to “i2c”.

If you’ve just got a keyboard connected, then run “sudo raspi-config”, then go into “Advanced Options”, then “i2c” and confirm you’d like to be enabled.

Finally reboot, and you should hopefully be set up!


#5

Hi - thanks for that - I’m afraid I resorted to buying a wi-fi dongle - re-ran the install and everything is working now :) - all I need now is some info about wiring it up :O - I have to say this one is a bit of a trial to work out how to get going - once I have worked it all out I can see one of my ‘Getting Started’ videos for numpties getting made :)


#6

The main - well, bar leds, very much only - difference between the Explorer pHAT and the Explorer HAT (pro) is the absence of the cap touch.

The explorerhat library is meant to recognise which Explorer flavour you have hooked up (by probing the devices on the i2c bus), so there is nothing particular for you to watch out for when reading any learning material made for the HAT, from a wiring point of view.

The main catch with (any) Explorer is that the 5v tolerant output operates through a darlington array, so some ‘traditional’ circuits may/would have to be reversed… quoting from the documentation:

Outputs, via ULN2003A: Explorer HAT/pHAT has a ULN2003A output driver. When you turn one of these outputs on ( logic HIGH ) it will sink current to ground. Be mindful of this when connecting to the output driver- you’ll need to connect your device to a voltage supply, and then to the output pin.