boomshockpow
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Joined: Tue Dec 27, 2016 3:42 pm

Using Pass-through for GPIO on pi zero / B+

Tue Dec 27, 2016 3:59 pm

I'm looking to make a portable GPS unit using my Pi zero or Pi B+. I already have Navit running smoothly and installed properly. I have a serial GPS unit on the way which I'm going to wire into the usb (or just plug in if I use the b+). I want to use a TFT touchscreen (probably the 3.5 inch) from adafruit. These things are not of any concern. The issue is that I want to have a small speaker that is powered by the pi itself. I think either way, if I want an internal speaker I need to use an amplifier like this one: https://www.adafruit.com/products/2130. But how can I use the screen AND the amp if I only have 40 pins? I don't understand how to make this work. Can I use passthrough headers? I just worry that If I use the passthrough, some functions of the TFT may not work.

jksmith
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Joined: Mon Mar 14, 2016 10:00 pm

Re: Using Pass-through for GPIO on pi zero / B+

Mon Jan 09, 2017 8:34 am

The amp you listed seems to require a regular audio signal. So you would just use a jack connector. You just need to provide 5V and GND and it should work. AFAIK, you can't get an audio signal directly from the GPIO pins.

alphanumeric
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Location: Sydney, Nova Scotia, Canada

Re: Using Pass-through for GPIO on pi zero / B+

Mon Jan 09, 2017 2:13 pm

The board you linked to appears to use an analog input. With any Pi other than a zero you use a cable like this, https://www.adafruit.com/products/1700 And solder the appropriate wires to the A+ A- connections on that board. Plus the 5V and ground from somewhere like the GPIO pins. If your using a Pi Zero that complicates things, it doesn't have an audio jack, and adding one is bit complex. https://learn.adafruit.com/introducing- ... io-outputs

One way around getting access to the GPIO pins and wanting to attach a Hat is to use a Proto Hat, https://www.adafruit.com/products/2310 Just swap out the header that comes with it for this one. https://www.adafruit.com/products/1979 Then plug the proto hat into your PI, and your hat on top of that. I have one between my Pi A+ and my Sense Hat. I have a DS3231 Real Time clock breakout board mounted to my Proto Hat, and thus connected to my Pi via GPIO. Wiring was easy as all the required GPIO pins are brought out and labeled. +5V, +3.3V and Ground too.

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aTao
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Location: Howlin Eigg

Re: Using Pass-through for GPIO on pi zero / B+

Mon Jan 09, 2017 2:22 pm

What sort of sound do you want the audio to do? beeps or voice or music?
>)))'><'(((<

hackware
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Joined: Thu Nov 19, 2015 4:13 am

Re: Using Pass-through for GPIO on pi zero / B+

Sat Jun 23, 2018 2:26 pm

I want another version of the pass through (stacking) connector...



I just bought a "justboom" hat for the pi-zero (hi-fi audio stereo), which has a female pass through connector...



used with extra tall header pins, you could put 2 or 3 hats on a pi...



I've tried various searches on google/ebay/adafruit/element14/arrow/etc... with no luck...



william...

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davidcoton
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Location: Cambridge, UK

Re: Using Pass-through for GPIO on pi zero / B+

Sat Jun 23, 2018 3:19 pm

hackware wrote:
Sat Jun 23, 2018 2:26 pm
used with extra tall header pins, you could put 2 or 3 hats on a pi...
If the boards conform to the HAT specification, they have an EEPROM on board that means they cannot be stacked.
Many Pi expansion boards are not actually HATS, in which case they can be stacked as long as they don't compete for the same i/o pins.
See https://pinout.xyz/ for some information about which boards use which pins.
"Thanks for saving my life." See https://www.raspberrypi.org/forums/viewtopic.php?p=1327656#p1327656
“Raspberry Pi is a trademark of the Raspberry Pi Foundation”

alphanumeric
Posts: 1499
Joined: Tue Jan 19, 2016 2:17 pm
Location: Sydney, Nova Scotia, Canada

Re: Using Pass-through for GPIO on pi zero / B+

Sat Jun 23, 2018 10:25 pm

Add to that that there are pHats, shims, bonnets, etc, all unofficial standards. And Hats that aren't officially Hats (no eprom). :? I'm fine with that actually, as I often stack more than one device on my Pi.

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