Selection of Raspberry Pi to work with Adafruit Sensor Hats

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adafruit_support_carter
 
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Re: Selection of Raspberry Pi to work with Adafruit Sensor Hats

Post by adafruit_support_carter »

Regarding the eInk display; what is the general rule of thumb for the interval between updates for these displays?
There really isn't one. Perhaps maybe 10s of minutes? Since eInk displays retain the display once power is removed, they pair nicely with applications that also go to sleep between updates. A good example is a daily weather forecast, which would run daily. Or maybe something that only updates hourly.

They're just a little more specialized in general. So having one as your *only* display option may be limiting in what you can do overall. You may want something that can update faster as part of the development or learning process, even if your final intent is something that only updates infrequently.

Are these easier/harder/comparable as far as programming them to display the data outputs?
Probably about the same. Since the libraries for each take care of the lower level details.
Other question regarding the Feather microcontroller; is it possible to get the data output to automatically get uploaded to an online database for data aggregation?
Yes. Checkout Adafruit IO as one option:
https://learn.adafruit.com/adafruit-esp ... ceive-data

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Re: Selection of Raspberry Pi to work with Adafruit Sensor Hats

Post by MRMayer »

You are the man, Carter. Thanks so much.

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Re: Selection of Raspberry Pi to work with Adafruit Sensor Hats

Post by MRMayer »

Carter,

Would this be the correct CircuitPython process/library to use in order to get readings from this SEN0129 sensor from DigiKey?
https://www.digikey.com/short/dw02d7bn

Write-up I found for Analog-In Sensors:
https://learn.adafruit.com/circuitpytho ... -analog-in

This is the sample Arduino code that their spec sheet includes:
SEN0129 Sample Code.jpg
SEN0129 Sample Code.jpg (52.43 KiB) Viewed 107 times
Also, I assume it's ok to share the ground and the USB (5v DC) outputs with the PM25 sensor and this SEN0129 sensor? The other pin I would need with this sensor is the A0 pin, I believe.
SEN0129 Sensor Pinout.jpg
SEN0129 Sensor Pinout.jpg (43.47 KiB) Viewed 107 times
For reference, this is my current board set-up/layout:
Current Board Layout.jpg
Current Board Layout.jpg (279.13 KiB) Viewed 107 times
Thank you!

-Matt
Current Board Layout.jpg
Current Board Layout.jpg (279.13 KiB) Viewed 107 times

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Re: Selection of Raspberry Pi to work with Adafruit Sensor Hats

Post by adafruit_support_carter »

Looks generally OK. One thing to be careful of is the mixed 5V and 3.3V level logic. The Feather is 3.3V but the SEN0129 is 5V. It's OK to power the SEN0129 with 5V, but you'll want to make sure the output signal, which is connected to an ADC pin on the Feather, does not exceed 3.3V. You could use a voltage divider to reduce the value if needed.

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Re: Selection of Raspberry Pi to work with Adafruit Sensor Hats

Post by MRMayer »

adafruit_support_carter wrote: Thu Mar 16, 2023 11:57 am Looks generally OK. One thing to be careful of is the mixed 5V and 3.3V level logic. The Feather is 3.3V but the SEN0129 is 5V. It's OK to power the SEN0129 with 5V, but you'll want to make sure the output signal, which is connected to an ADC pin on the Feather, does not exceed 3.3V. You could use a voltage divider to reduce the value if needed.
Carter,

Does Adafruit sell a voltage divider? I looked on the site but didn't see anything listed as a voltage divider. And just to be clear; was the link I supplied previously for the Analog-In the correct way to get the readings from this sensor with the correct libraries/etc?

Lastly, what are your thoughts on using WipperSnapper for this? I got there from when you previously suggested that I look at Adafruit IO and it seems like the WipperSnapper would *replace* the code I currently have in the code.py file and then it would automatically identify the sensors and write the code to use to get the data off of them and up into the Adafruit IO dashboard?

Thanks again!

-Matt

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Re: Selection of Raspberry Pi to work with Adafruit Sensor Hats

Post by adafruit_support_carter »

A voltage divider is just two resistors:
https://en.wikipedia.org/wiki/Voltage_divider
so generally won't be anything sold as a separate item.

The SEN0129 sensor's output is analog, so does not require any special library. Reading an analog input is a generic function. The only special treatment needed would be to turn the raw analog reading value (counts) into a value of interest (some gas value), which would just be math and something the sensor maker would provide.

By comparison, the SDC41 communicates over I2C. So a library is used to take care of all the I2C details and provide you with simple functions you can call to get the sensor reading.

WipperSnapper has the tradeoff of providing a no-code option, but only for supported boards and sensors.

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Re: Selection of Raspberry Pi to work with Adafruit Sensor Hats

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Carter,

Would this display work? The options you suggested are out of stock both on Adafruit and through Digikey.

Thank you,

-Matt

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Re: Selection of Raspberry Pi to work with Adafruit Sensor Hats

Post by MRMayer »

Carter,

I'm just realizing I didn't include the link to the display that was hoping you could tell me would work or not. Unfortunately, the other ones you previously suggested are still not in stock.

https://www.adafruit.com/product/2050

Thank you!

-Matt

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Re: Selection of Raspberry Pi to work with Adafruit Sensor Hats

Post by adafruit_support_carter »

Yep, that display should work. It's the same TFT that is on the FeatherWing (PID 3651). It will just require more work to make all the connections for the breakout version (PID 2050). The associated guide covers the necessary connections:
https://learn.adafruit.com/adafruit-3-5 ... n-breakout

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Re: Selection of Raspberry Pi to work with Adafruit Sensor Hats

Post by MRMayer »

Thank you, Carter. I have placed an order for one. Fingers crossed I can stumble my way through it again.

S/F,

-Matt

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