KE1THA
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Using Sense HAT with other HATs

Thu Mar 16, 2017 12:38 am

I am planning to use my Sense HAT along with four relays (on another HAT).
The project is to make a portable satellite tracker. I have most of the hardware on hand, RPi, Sense HAT, Pan/Tilt head, and misc support items. Preparing to purchase a relay HAT to drive the Pan/Tilt unit when I realized I'm missing some info...

I cannot find what IO the Sense HAT is using. I have just located the Python code to access it.
I'm concerned there may be GPIO conflicts between multiple HATs.
Can anyone provide the actual pin-out usage of the Sense HAT?

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DougieLawson
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Re: Using Sense HAT with other HATs

Thu Mar 16, 2017 7:19 am

HATs are not stackable. That's been the fundamental part of the the design since the B+ came out.

You can probably work out which pins (I²C, SPI, etc.) are used by starting at https://pythonhosted.org/sense-hat/api/ then reading the supplied python code behind that API.
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scotty101
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Re: Using Sense HAT with other HATs

Thu Mar 16, 2017 7:56 am

The pin out for the Sense HAT pin out and many more HATs can be easily found on the following website.

https://pinout.xyz/pinout/sense_hat
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Pi Interests: Home Automation, IOT, Python and Tkinter

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DougieLawson
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Re: Using Sense HAT with other HATs

Thu Mar 16, 2017 8:46 am

scotty101 wrote:The pin out for the Sense HAT pin out and many more HATs can be easily found on the following website.

https://pinout.xyz/pinout/sense_hat
Ah ha, I forgot they'd done that useful stuff on there.
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davidcoton
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Re: Using Sense HAT with other HATs

Thu Mar 16, 2017 1:31 pm

DougieLawson wrote:HATs are not stackable.
That is true for a full HAT implementation with eeprom on board -- the sense hat is such. The eeprom enables the OS to identify the hat and configure drivers. Butr the hardware can only handle one eeprom at a time -- two will cause conflict.
The relay board probably does not have eeprom on board, no problem there. After that you just need to know what GPIO pins are used by each board, and whether any of them conflict (the i2c bus is designed for sharing, but most GPIOs are not).
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KE1THA
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Re: Using Sense HAT with other HATs

Thu Mar 16, 2017 2:24 pm

Thanks to all for the info. I will build my own relay interface to use the open gpio and set this in between the rpm and hat with a pass through header.

alphanumeric
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Re: Using Sense HAT with other HATs

Thu Mar 16, 2017 7:59 pm

I used this, https://www.adafruit.com/products/2310 and swapped the header that comes with it for this one, https://www.adafruit.com/products/1979 I have a RTC breakout board wired to it. I have it between my Pi and sense hat. Just make sure to get the one with no eprom. The GPIO pins are all nicely brought out to solder pads and labeled for you.

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