BLE without USB?

[ahd11]

Hi.  I apologize in advance if this question is in the wrong place or is too elementary for this location/audience.  I have prototyped a product using two Nano 33 BLE arduinos which are "based on" the NRF52840 board.  It's for a wearable product that needs BLE and the two boards draw between 15 mA and 20 mA each which is too much for my use case.  I have read that the USB port on an arduino is responsible for most of its power consumption, perhaps all but 1mA.  So, my question:  Is there a board that I can purchase for a production product that is like a Nano 33 BLE arduino without the USB port, and is programmable either via BLE or via an existing pin (maybe the SWD pin)?

[Edvin]

Perhaps you can use the nRF52840 dongle? If you don't connect the USB, and your app doesn't use USB, I it will not draw that much power.

Of course, the best option would be to have a custom pcb with only the HW that you need.

[ahd11]

Thanks, Edvin.  I guess I'm still confused.  Following the link and looking at the product brief, it looks like the dongle is intended to plug into the USB port of the nRF52840.  But it's the USB port that is power-hungry so I don't see how the dongle eases my problem.  I wonder if it's possible to disconnect the USB port (either physically or programmatically) after the board has been programmed and eliminate it's power draw?

[Edvin]

Hello,

It is possible to power the nRF52 Dongle without the USB. I guess if you are plugged in a USB port, then you have a lot of power, right? (If you are plugged in a computer). And if you are not, you can power it using the VDD out pin, as described here:

https://infocenter.nordicsemi.com/topic/ug_nrf52840_dongle/UG/nrf52840_Dongle/hw_description.html?cp=4_0_5_5

However, I am not familiar with the arduino board, and what's present on that board, and what may draw power. There are probably more devices that the nRF52 chip on the arduino. But on the nRF52 dongle, if your application isn't really using the USB for anything sensible, it will only be used to power the nRF, so I don't think it will draw as much power. 

BR,

Edvin