topic Re: D435 Power Management in Items with no label

D435 Power Management

aardee — Wed, 22 Aug 2018 16:37:04 GMT

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!

Re: D435 Power Management

MartyG — Wed, 22 Aug 2018 17:03:02 GMT

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.

Re: D435 Power Management

aardee — Wed, 22 Aug 2018 17:24:25 GMT

Thanks for the link MartyG!

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

Re: D435 Power Management

MartyG — Wed, 22 Aug 2018 17:48:11 GMT

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.

Re: D435 Power Management

aardee — Wed, 22 Aug 2018 18:06:42 GMT

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.

Re: D435 Power Management

MartyG — Wed, 22 Aug 2018 18:23:09 GMT

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

Re: D435 Power Management

aardee — Wed, 22 Aug 2018 18:29:33 GMT

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

Re: D435 Power Management

MartyG — Wed, 22 Aug 2018 18:48:26 GMT

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.

Re: D435 Power Management

aardee — Wed, 22 Aug 2018 18:52:30 GMT

Thanks Marty!

Re: D435 Power Management

MartyG — Wed, 22 Aug 2018 19:16:22 GMT

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.

Re: D435 Power Management

aardee — Wed, 22 Aug 2018 20:11:22 GMT

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!