D435 Power Management

[aardee]

The Realsense D435 draws 110mA from the USB port on connection, and while it's running as shown below using the "lsusb -v" command:

Bus 002 Device 003: ID 8086:0b07 Intel Corp.

MaxPower 110mA

Is there a way to get the camera to 'sleep' so as to draw lesser current?

Thanks!

[MartyG]

At the link below, you can find scripting for disabling the laser by setting its Laser Power to '0' or restoring its power by setting Laser Power to 'max'. For code that works with the D435's RealSense SDK 2.0, please look under the 'Librealsense2' heading.

https://github.com/IntelRealSense/librealsense/wiki/API-How-To# controlling-the-laser API How To · IntelRealSense/librealsense Wiki · GitHub

A more brute-force method of disconnection after a certain period would be to set power-saving on the USB port in your operating system.

[aardee]

Thanks for the link MartyG!

Is the laser turned on automatically when I connect the USB cable?

[MartyG]

I considered your question carefully. Power provided by USB initially goes to the Vision Processor D4 board in the camera, and is passed on to the depth module from there by the D4 board. Here are the power supply requirements of the D4:

Whilst I do not have definite technical knowledge of this subject, my unofficial expectation would be that the camera would draw a small amount of 'standby' power when inserted (like the light on the bottom of mice and lights on keyboard LEDs) but would not draw greater power until a stream is activated and the laser powers up.

The RealSense 400 Series cameras are very power-efficient though, more so than previous RealSense generations.

[aardee]

So is 110mA like a 'standby' current draw? I ask because the port draws 110mA even when I turn on realsense-viewer or use ROS to launch the camera node.

[MartyG]

I researched the 110ma power draw, and it seems to be a common power usage for a wide range of USB devices.

[aardee]

Then I guess it just needs 110mA generally, but can go up to 700mA?

[MartyG]

I thought about the question carefully but any statement I could offer would be speculation. A member of Intel Support on this forum will be better able to provide official guidance about max power draw when the camera is in standby.

[aardee]

Thanks Marty!

[MartyG]

Digging through my memory of electronics, I had the recall that 110 ma is equal to 5v output voltage. USB 3.0 provides power at 5v nominal.

[aardee]

That was very helpful MartyG! The 110mA was the 5V that the USB 3.0 provides. The current drawn by the Realsense is 440mA after launching.

Thanks again!