hostingnuggets
Posts: 34
Joined: Fri Dec 28, 2012 5:52 pm

Two HATs together (PoE+Blinkt!)

Wed Apr 10, 2019 7:44 pm

Hello,

I have a Raspberry Pi 3b+ and would like to know if it is somehow possible to have two HAT on this single Raspberry Pi. The two HAT which I would like to have together are the following:

- PoE HAT: https://www.raspberrypi.org/products/poe-hat/
- Blinkt! HAT: https://thepihut.com/products/blinkt

As you can see none of these two HATs have additional pins which I could stack one HAT on top of the other one. Maybe there is a small extender board? Ideally I would not extend in the height but in the width as I plan to have a few of RasPi stacked on top of each other in a small rack.

Anyone know is there is any hardware for that or have an idea?

Regards,
John

Andyroo

Re: Two HATs together (PoE+Blinkt!)

Wed Apr 10, 2019 8:06 pm

You can get boards that will let you PHYSICALLY connect multiple HATs to one Pi such as https://shop.pimoroni.com/products/phat ... 8973392906

They may clash. The best way, other than contacting the manufacturer, is to use https://pinout.xyz and the Pimoroni checker at https://pinout.xyz/phatstack that may help.

Remember to check power needs :lol:

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HawaiianPi
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Location: Aloha, Oregon USA

Re: Two HATs together (PoE+Blinkt!)

Wed Apr 10, 2019 8:17 pm

This one adds a second right-angle GPIO header (kit: requires soldering).
Image


This one gives you 3 GPIO expansion headers (fully assembled).
Image
Pictures are links.

You can find similar products on eBay, AliExpress and some Pi dealers. Adafruit/PiMoroni sells a dual GPIO PCB similar to the one included in the first one if you want to roll your own (just the PCB, with connectors available separately).
My mind is like a browser. 27 tabs are open, 9 aren't responding,
lots of pop-ups...and where is that annoying music coming from?

Andyroo

Re: Two HATs together (PoE+Blinkt!)

Wed Apr 10, 2019 8:39 pm

It’s just dawned on me - does not the POE use pins on the main board of the Pi to provide power to?

In this case you will just need to connect the lights or expansion board to the top of the POE card.

Still check if there is any clash as both devices are linked to the Pi.

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rpdom
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Location: Chelmsford, Essex, UK

Re: Two HATs together (PoE+Blinkt!)

Thu Apr 11, 2019 5:09 am

The design of the PoE HAT makes it possible to put some long pin header extension on the Pi, then plug the hat on top (you will need some extensions for the four PoE pins as well). The pins will stick out the top of the hat and allow another HAT to be stacked on top.

The PoE HAT is the only HAT that (currently) supports another HAT being connected at the same time.

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B.Goode
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Joined: Mon Sep 01, 2014 4:03 pm
Location: UK

Re: Two HATs together (PoE+Blinkt!)

Thu Apr 11, 2019 8:06 am

rpdom wrote:
Thu Apr 11, 2019 5:09 am
The design of the PoE HAT makes it possible to put some long pin header extension on the Pi, then plug the hat on top (you will need some extensions for the four PoE pins as well). The pins will stick out the top of the hat and allow another HAT to be stacked on top.

The PoE HAT is the only HAT that (currently) supports another HAT being connected at the same time.


Picking up that latter point and expanding/emphasising (not contradicting)...

"The PoE HAT is the only HAT that (currently) supports another HAT being connected at the same time."


The specification for a genuine HAT includes a personality/configuration eeprom, accessed via physical pins #27 and #28. For that reason, HATs are not stackable. The PoE HAT is an exception as noted.


However.. the Blinkt add-on is not a HAT...

hostingnuggets
Posts: 34
Joined: Fri Dec 28, 2012 5:52 pm

Re: Two HATs together (PoE+Blinkt!)

Thu Apr 11, 2019 1:49 pm

First thank you all for your answer and suggestions.

The easiest and nicest way seems to be @rpdom's suggestion of using a long pin extension header on my RasPi and then stack the PoE and finally the Blinkt!.

Now I was wondering if this extension header would be long enough to do the job:

https://uk.pi-supply.com/products/40-pi ... ing-header

or else where can I find/buy a longer pin extension? I did not find anything longer on the pi-supply.

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