When I start the board by connecting USB, the arduino pins (9, 10, 11) are HIGH, correctly. When I connect the board to the circuit with it's own external power supply, the pins are LOW, except pin 11 which is at 0.19V. I don't have the loads connected.
I measured the GND/VIN and it is correctly 5V. The VCC/GND is correctly 3.3V.
Materials:
MKR Zero
IRL8721 MOSFETs
Schottky Diodes 1N5819
100Ω Resistors
10KΩ Resistors
5V 1A Power supply
Here is a diagram. Note that the arduino is upside down here:
And my code:
#include <Arduino.h>
const int pins[3] = {9, 10, 11};
void setup() {
Serial.begin(9600);
Serial.println("Starting...");
for (int i = 0; i < 3; i++) {
pinMode(pins[i], OUTPUT);
digitalWrite(pins[i], HIGH);
}
}
void loop() {
Serial.println("nothing...");
delay(1000);
}
Thanks, I've added another schematic. Is this what you're looking for? The post you linked does give many details on what a proper schematic is:
A schematic is a drawing of what connects to what; please make one and photograph it. We don't mind if it's hand drawn, scruffy and does not use the correct symbols, but please make sure it is accurately and completely labelled.
You need Vin to be about 7.5V or greater. Vin is the input to the on board 5V regulator and it has a drop out voltage maybe a volt.
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No, that's not correct for most "Arduinos". Vin is likely way too low.
"Arduino" is not precise enough for the controller. Which one out of plenty?
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I mention in my original post it’s the MKR Zero.
Thanks for the info. When I say “correct” I mean that it matches the voltage of the power source I’m using.
When you say “that’s not correct” what do you mean? Where can I find more info on this?
You need Vin to be about 7.5V or greater. Vin is the input to the on board 5V regulator and it has a drop out voltage maybe a volt.
Ok. Then how is VCC showing correct 3.3V? Maybe I’m misunderstanding. Can I use a 5V power source for the arduino MKR zero?
It's a USB power source which is 5.1VDC commonly called 5VDC. Is your 'external power supply' a wall wart? That is a device that plugs into mains power and can charge a phone or similar using 5VDC at about 1 to 2 amps with a few nwer models as high as 3A. What is on the label of your device?
Yes the wall wart is 5V 1A. model: ALT 0501
That is weird. Do you have another wall wart? We often see where a project will not work when no longer connected to the PC USB power due to a weak battery, but a wall wart is always the sure fire solution so I am mystified. One thing to check is how many amps the circuit needs, the PC can supply a lit more than the 1A wall wart, try to find a 2A or more.
Yeah it’s weird. The loads are not connected when the issue happens so I don’t think amperage is the issue.
Use a meter and measure it, assumptions can be flawed.
Use a meter and measure it, assumptions can be flawed.
Thanks, yeah I've measured with a multimeter. Is there something specific you're asking about?
Here are some measurements that I've taken:
Arduino connected to USB, no circuit:
5V: 5V
VIN: 0V
Pin: 2.09
Arduino connected to powered circuit:
5V: 5.29V
VIN: 5.27V
Pin: 0V
Turning the MKR Zero on and then connecting it to the circuit works like the first case. In that case, the MOSFET module works correctly
I was referring to the current. If there is too much demand on the wall wart it may cause a problem.
TBH, I am not sure what you are showing re the voltage measurements, why is the first set 0V on VIN?
Because it's powered by USB.
Ok, I don't really like your diagrams so I can't contribute, good luck.
Ah I misunderstood. Where are you looking for a current reading?
Sorry, is there a way I could improve? I laid it out the way I need it physically on the perfboard.
For the main 5V feed. For USB I have a meter that plugs into the USB socket, for the wall wart if it ends in a USB then use the same thing, otherwise use a VOM. Here is a sample on Amazon.ca. Get one or more depending on USB version. I have USB-A to USB-C converters.
https://amz.cx/3RVD
