Author Topic: How to power both the fan and the RTC  (Read 1771 times)

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Offline kbellis

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How to power both the fan and the RTC
« on: January 14, 2019, 08:14:58 AM »
The case I'm getting for the 3B+ has a little fan that gets pinned to the board using what looks like the same pins as the RTC sits on - is it possible to get both items connected to the RPi and if so how?

Thanks.

Kelly

Offline Storm017

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Re: How to power both the fan and the RTC
« Reply #1 on: January 14, 2019, 09:39:09 PM »
RPI3B+ GPIO Pins:
Pin 1 ---- 3.3 Volts
Pin 2 ---- 5 Volts
Pin 4 ---- 5 Volts
Pin 6 ---- GND
Pin 14 ---- GND

I2C Pins
Pin 3 ---- SDA
Pin 5 ---- SCL

https://www.theengineeringprojects.com/2018/07/introduction-to-raspberry-pi-3-b-plus.html

I wired my fan to GPIO Pins 4 and 6.  I'm using a DS3231 RTC which is mounted on a breadboard.  Wired GPIO Pin 2 to the power rail and Pin 14 to the ground rail of the breadboard, which in turn are wired to the appropriate pins on the DS3231 RTC. Wired GPIO Pin 3 to the SDA and GPIO Pin 5 to the SCL pins on the DS3231 RTC.  If I want to add additional I2c sensors, I just need to extend the I2c bus on the breadboard.





Offline kbellis

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Re: How to power both the fan and the RTC
« Reply #2 on: January 15, 2019, 06:23:42 AM »
Thank you for the link. I'll study it more intently after my kit arrives later this week.

The original question is contained within the case without an external breadboard. The RTC rests on the pins.

Offline Storm017

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Re: How to power both the fan and the RTC
« Reply #3 on: January 15, 2019, 07:42:31 AM »
No problem, I realized that later; Mine is just a module in which I installed the header.

Offline nincehelser

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Re: How to power both the fan and the RTC
« Reply #4 on: January 15, 2019, 07:57:26 AM »
I'm not sure I understand your question.

The RTC module you specified provides a pass-through connection so you can hook up the fan, too.

If your question is if that particular case provides enough clearance, I don't know.

Personally, I've never found fans or heat sinks necessary for my projects. 

Offline Bushman

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Re: How to power both the fan and the RTC
« Reply #5 on: January 15, 2019, 10:15:53 AM »
I  use the included heat sinks (even tried a couple of copper ones) but a fan for a Pi?
« Last Edit: January 15, 2019, 10:36:47 AM by Bushman »
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Offline vreihen

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Re: How to power both the fan and the RTC
« Reply #6 on: January 15, 2019, 12:13:41 PM »
I  use the included heat sinks (even tried a couple of copper ones) but a fan for a Pi?

Fans are generally only needed by those using the Pi as a video streaming receiver, where decompression of the stream really taxes the CPU.....
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Offline kbellis

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Re: How to power both the fan and the RTC
« Reply #7 on: January 16, 2019, 06:46:21 PM »
Thank you all who replied.

Is there something akin to consensus on whether an RTC is even necessary?

Offline kbellis

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Re: How to power both the fan and the RTC
« Reply #8 on: January 16, 2019, 07:00:31 PM »
You bring up an excellent point, and I don't think both items will fit within the case.

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I'm not sure I understand your question.

The RTC module you specified provides a pass-through connection so you can hook up the fan, too.

If your question is if that particular case provides enough clearance, I don't know.

Personally, I've never found fans or heat sinks necessary for my projects.

Offline vreihen

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Re: How to power both the fan and the RTC
« Reply #9 on: January 16, 2019, 07:22:06 PM »
Is there something akin to consensus on whether an RTC is even necessary?

If you are planning to use your Pi for capturing weather data with weewx, there is a whole page in the weewx wiki on the subject.  I never used an RTC module on any Pi before reading that, and now put them into all new Pi's just to have them.....
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Offline kbellis

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Re: How to power both the fan and the RTC
« Reply #10 on: January 16, 2019, 07:30:20 PM »
Yes, for capturing wx data; however, am uncertain about the downstream client just yet.

Thanks.

Offline nincehelser

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Re: How to power both the fan and the RTC
« Reply #11 on: January 16, 2019, 08:29:59 PM »
Thank you all who replied.

Is there something akin to consensus on whether an RTC is even necessary?

It depends on your application.

If you are on a solid network with access to reliable time servers, you can get by without an RTC easily.

However, with my first Pi/Weewx installation how found how useful a RTC can be during severe weather.  Without an RTC, if the system resets while the network is down, your recorded data can get really screwed up.  While there are other ways to mitigate this problem, falling back on the RTC is typically the best.