Adding an RTC through a STEMMA shim

Moderators: adafruit_support_bill, adafruit

Forum rules
Talk about Adafruit Raspberry Pi® accessories! Please do not ask for Linux support, this is for Adafruit products only! For Raspberry Pi help please visit: http://www.raspberrypi.org/phpBB3/
Locked
User avatar
facets
 
Posts: 3
Joined: Mon Jul 05, 2021 11:02 pm

Adding an RTC through a STEMMA shim

Post by facets »

I apologize in advance if this is a question I could have answered by reading the docs.

I need to add an RTC to a raspberry pi in addition to a full HAT (specifically the Automation HAT). Could I combine the STEMMA shim with the STEMMA DS3231 breakout for an equivalent setup to the DS3231 PiRTC?

User avatar
dastels
 
Posts: 15653
Joined: Tue Oct 20, 2015 3:22 pm

Re: Adding an RTC through a STEMMA shim

Post by dastels »

There's already an I2C expansion connector on the back of the hat. It's not stemma, but it looks like https://www.adafruit.com/product/4209 would do the job.

Otherwise, yes, a shim should work as long as it doesn't interfere with mounting the hat. HOWEVER, I put no faith in the way the shim connects to the pi header. It's friction fit and assumes no dirt of corrosion. Ok, sure, so does the I2C connection on the hat, but it's a connector designed to be a good connector. It has more connecting surface area and is spring loaded to create a snug grab of the inserted pins.

Dave

User avatar
facets
 
Posts: 3
Joined: Mon Jul 05, 2021 11:02 pm

Re: Adding an RTC through a STEMMA shim

Post by facets »

Good point about the friction fit. Since my application is pretty rattly, I'll just have to carefully solder the shim on, and the permanent addition of an I2C expansion won't be a tragedy. The HAT doesn't expand the I2C bus, though; that silkscreen text that happens to be near the GPIO header is just telling the user the address for the analog channels (the ADC chip is an ADS1015 or ADS1115, address 0x48).

Thanks!

User avatar
dastels
 
Posts: 15653
Joined: Tue Oct 20, 2015 3:22 pm

Re: Adding an RTC through a STEMMA shim

Post by dastels »

Doah! I was looking at the Automation Hat Mini.

Your approach sounds reasonable.

Dave

Locked
Forum rules
Talk about Adafruit Raspberry Pi® accessories! Please do not ask for Linux support, this is for Adafruit products only! For Raspberry Pi help please visit: http://www.raspberrypi.org/phpBB3/

Return to “Adafruit Raspberry Pi® accessories”