Argon power connection


I am looking for the preferred way to power the Argon using an external power source. We will not be using LiPo or USB.

On the Photon we would connect a 5v supply to Vin. I don’t see a Vin pin on the Argon. Do we use the Vusb pin at 5v? It it written in the docs as it’s output only. Or is it preferred to use the 3.3v pin and disable onboard regulator?

Please advise and thank you!


According to diagram in the docs, Vusb is your best bet. Just note, there is no protection for the USB port so don’t connect USB and Vusb at the same time.


Thank you. That was my thought as well (it is a bus after all), though a confirmation would remove all doubt.

Yes, 5V to VUSB is the best option. However, be careful because unlike the Photon, there isn’t a Schottky diode between the USB connector and VIN, so you should not power by VUSB and USB at the same time.


Thank you for the confirmation! Yeah, I see that being a problem. I inevitably forget to connect the power at times.

Hi, I ran into some issues connecting a 5V PSU to the VUSB pin. Oddly enough, my argon device always ‘reset’ itself in listening (blinking blue) mode when I cycled the power of my PSU. I can setup the device again, but setup is reset ever time the power cycles.
Any ideas? (of would investing in a 3V3 PSU be the better option here…)

What kind of 5V PSU? A true switching PSU or just a voltage regulator? How do you power cycle that PSU? How much current does the PSU draw at power-up? Do you have any additional capacitance added the the Vusb pin? Do you have another power source attached to the device such as a USB cable from a PC or something? A schematic would go a long way.


I’m using a 5V switching PSU, which I’ve used for some years to power cores and photons without any issues. As you’re hinting towards, I’m guessing there’s probably a current peak on power up, unfortunately I don’t have the tools at had to get good measurements right now.
I’ll try adding a 1000 µF capacitor to the vusb pin and see where that ends up.


Hi Folks!
I had an issue which matched @driesderoeck 's situation and the root cause for me was the breadboard.
The breadboard with issues had higher resistance everywhere but specifically the negative rail was 0.7 Ω vs typical 0.1 Ω.

Power Supply: Adafruit MPM3610 5V Buck Converter Breakout - link

External Power Input: 12V

OK: DEYUE breadboard Set Prototype Board - link
NG (No Good): ELEGOO 3pcs Breadboard 830 Point Solderless Prototype PCB Board Kit - link

No issues with OK breadboard: (Video)

Argon Continuous Resetting with NG breadboard: (Video)