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Breadboarded Feather M4 Express safe to connect to my MacBoo
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Breadboarded Feather M4 Express safe to connect to my MacBoo

by s_k on Thu Aug 15, 2019 2:32 pm

If I breadboard a Feather M4 Express, a servo, and a RTC FeatherWing, is it safe to connect the Feather M4's USB port to my MacBook's USB port (so I can alter the CircuitPython script)?

If I use an external 5v supply can I leave it connected?

The servo is this one, which I gather the Feather M4 can power directly:
https://www.adafruit.com/product/169
The RTC FeatherWing is this one:
https://www.adafruit.com/product/3028

I am in the pre-planning stage. Trying to visualize how this is going to all go together. This will be my first micro controller project.

Thank you.

s_k
 
Posts: 16
Joined: Wed Oct 10, 2018 2:39 pm

Re: Breadboarded Feather M4 Express safe to connect to my Ma

by adafruit_support_carter on Thu Aug 15, 2019 3:24 pm

How will you connect the servo the Feather?

How will you connect the 5V power supply to the Feather?

adafruit_support_carter
 
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Joined: Tue Nov 29, 2016 2:45 pm

Re: Breadboarded Feather M4 Express safe to connect to my Ma

by s_k on Sat Aug 17, 2019 2:59 pm

For the Feather M4, should I follow the illustration for the Feather M0 on this page
CircuitPython Servo | CircuitPython Essentials | Adafruit Learning System
<https://learn.adafruit.com/circuitpython-essentials/circuitpython-servo>
or this page
Hardware | Using Servos With CircuitPython and Arduino | Adafruit Learning System
<https://learn.adafruit.com/using-servos-with-circuitpython/hardware>
They appear to be different?

For power I thought I would use either this 2x2 AA battery pack:
2x2 AA Battery Holder with Premium Jumper Header Wires ID: 3905 - $2.95
<https://www.adafruit.com/product/3905>
or this 5v power supply:
5V 2A Switching Power Supply w/ USB-A Connector ID: 1994 - $6.95
<https://www.adafruit.com/product/1994>
I have both on hand.

What do you think?

Eventually, I might add a backup battery so it could tolerate brief mains power interruptions, such as perhaps this one (which I have not yet bought):
Lithium Ion Polymer Battery Ideal For Feathers - 3.7V 400mAh ID: 3898 - $6.95
<https://www.adafruit.com/product/3898>

I probably should just start soldering on headers and get going with this, but I would like to have what I recently heard someone call a "mental model", before I plug in the soldering iron. :-)

s_k
 
Posts: 16
Joined: Wed Oct 10, 2018 2:39 pm

Re: Breadboarded Feather M4 Express safe to connect to my Ma

by adafruit_support_carter on Mon Aug 19, 2019 12:10 pm

The servo will need 5V power. However, the PWM control signal is often fine at the 3V level. So you can use either of those wiring diagrams shown. The one here:
https://learn.adafruit.com/circuitpytho ... thon-servo
is getting the 5V power from the USB port.
The wiring shown here:
https://learn.adafruit.com/using-servos ... n/hardware
is using an external battery pack to power the servo. Note that it is a 4xAA battery pack. A 2x pack would only be about 2x1.5 ~= 3V, so not enough to power the servo.

So in your case, you could the 5V/2A USB supply and wire as shown in the first link.

adafruit_support_carter
 
Posts: 12958
Joined: Tue Nov 29, 2016 2:45 pm

Please be positive and constructive with your questions and comments.