Stacking MKR Connector Carrier with MKR Relay Proto Shield and MKR GSM 1400

Official Hardware MKR Family MKR Shields
1

Hi

I noticed MKR GSM 1400 requires an external power source to work since the USB port can provide only 500mA and a fully functioning board requires 2A due to GSM modules consumption.

In my project I need a power adapter from my 12-16 VDC power source to the Arduino MKR GSM 1400 that runs as the heart of my project. I also need a couple of relays and a connector for a sensor that in the future may increase in numbers and variety.

I would like to use the power adapter and a connector of the Connector Carrier. I would also like to use the relays and the features of the relay shield. The only alternative I could find is the overly expensive Controller edge that also includes the relays in latch mode that I really need (not just a relay).

But then I had an epiphany. I know they are not meant to be stacked since the bottom of the shields do not include the pins for the next one. But could it work if I do not use a couple of the connectors from the first shield and leave untouched the power source of the relay shield? I went through the pins but got lost. I am still in the beginners stage here.

Thanks!

2

I recommend you to find a solution without the Connector Carrier. You could use a 5 V 2 A phone charger

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There is no electricity (110-220VAC) at the installation place. We are using solar to get those 12 to 16 volts feeding the project.

4

Just in case it helps.

The relay board just uses pins D1 and D2 to command the relays, meaning I/O1 and I/O2 at the connector board are "used".

I cannot figure out the effect the resistors placed on pins A1 to A4 at the relay board, although for now I can just not use those connectors at the connector board.

But what puzzles me most is the bunch of resistor based voltage dividers connected there. Why? What would a voltage divider accomplish at an exposed pin to the outside of the board while connected in the missile to one of the analog I/O pins?

Thanks

5

I have the feeling I an over thinking this.

I could just stack the GSM 1400 on top, then the connector board in the middle, then the relay at the bottom letting only 3.3v, GND, D1 and D2 down to it for the top, right?

Still I wonder if there would be enough power coming out of the power stage of the connector board to make both shields work at the same time the GSM module sucks the juice for the GSM communications.

I apologise for answering my own questions but I still feel I am concluding something wrong along the way that just slips though my fingers.

Any hints?

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You are right. I am over thinking it. Connector board with a connected relay is cheaper and less troublesome. Thanks!

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