Feather R3 Adapter

Details

This is a project for the Adafruit Feather series of boards. This dual purpose FeatherWing Arduino R3 adapter allows you to plug in your feather board and have the I/Os broken out to the Arduino R3 layout for use with other shields that are not available as Feather Wing shields. You can also run it backwards too. Meaning you could use a FeatherWing shield like a R3 shield for a different MCU! The shield supports the standard Feather pin-out so it should be compatible with all Feathers. It interconnects the I2C and SPI bus along with the analog and digital pins. It also features two switches for additional configuration (mainly for the Huzzah ESP8266 Feather) and also incorporates a voltage divider for monitoring the battery. The first switch ties, the Huzzah ESP8266 Feather, GPIO16 (wake pin) to RESET pin for use with deep sleep. The second ties the raw battery voltage to A0 via a voltage divider with a max output of 1.0v so the battery can be read if one wishes. Both can be switched off to free A0/GPIO16 for normal IO use. As of right now only supports 3.3v logic. Another version to come soon to support level switching.

Benefits

Make use of other shields/boards
Controllable battery voltage monitoring
Controllable reset to wake from deep sleep
Battery connection on shield, 3.7-4.2v batteries
Reset switch resets both board and shields
Shield power LED
AREF supported

Notes

Supports 3.3v shield powering via battery, 5v powering via usb on feather
Supports 5v & 3.3v MCU powering
Supports 3.3v logic currently
Digital pins 11, 12 & 13 not usable with SPI connection on ESP8266 Feather

Future Features...

Logic Level shifting ( supporting both 3.3v and 5v logic )
Disable/enable 3.3v LDO
Controllable power routing

Files

layout.sch

Board Schematic

sch - 297.53 kB - 12/29/2019 at 19:32

Download

layout.brd

Board Layout

brd - 64.44 kB - 12/29/2019 at 19:32

Download

Components

3 × Resistor 2 for voltage divider, one for led(depending on color)

1 × Dual Switch for selecting options

1 × Push button momentary switch for reset

1 × LED for power indicator

1 × JST-PH connector for battery connection

Project Logs

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Got Boards

Mitch • 01/08/2020 at 23:34 • 0 comments

Got the PCB today & uploaded a couple photos of it. Yay!

The waiting begins

Mitch • 12/28/2019 at 06:40 • 0 comments

ordered the PCB today. Can’t wait for it to get here!

Discussions

bobgreenwade wrote 08/31/2020 at 14:35

If one uses short headers to put the Feather on top of this Shield, can one stack another Shield on top?

Are you sure? yes | no

Mike Pate wrote 07/05/2020 at 15:08

Great project and was looking for this exact solution. I'm new to Hackaday so not sure where to obtain the details on the components (i.e. resistor values, LED, part numbers). Also what is the purpose of the 2-position switch?

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Mark Aldritz Dela Virgen wrote 12/27/2019 at 09:38

Suggestion: Add a 3.3V<--->5V level shifter. The UNO uses 5V logic, and the feather uses 3.3V logic.

I want to see if this thing can work both ways. (R3+FeatherWing and Feather+Shield)

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Mitch wrote 12/27/2019 at 10:06

I thought about implementing that but unsure the best way to do it. I need to think about it some more. I planned on using 3.3v logic shields with it or at least dual logic.

Thanks for the comment!

Are you sure? yes | no

bobgreenwade wrote 01/09/2020 at 00:22

Level shifting (and voltage shifting) will be a challenge to plan out, since it's impossible for a designer to predict which direction the board will be operating in (Feather to Arduino or Arduino to Feather), and whether there even will be 5V logic involved. For your own purposes, I think you're fine leaving it as it is; for a commercial venture, I'd recommend including the parts for all of the above, but requiring a solder jumper or some similar mechanism to make them active (it may require a pair of DPDT slide switches with a center-off position, or something even more funky).

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Ted wrote 03/24/2021 at 22:02

I think you could do it with something like: https://www.hobbytronics.co.uk/mosfet-voltage-level-converter

e.g. https://www.sparkfun.com/products/12009

It might not work for everything, but I expect it would work for most cases.

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Feather R3 Adapter

Description

Details