I have some questions regarding Intel’s RealSense camera and power consumption.
We are thinking to use Intel RealSense camera with Raspberry Pi. How much power will they consume and will the battery be enough for both of them and the motors?
Did someone used Intel RealSense before?
Our mentor told that in the match, there may be power restrictions, they may lower the power you draw because maybe there is a limit of it. He said what we test here might not work at the match because there can be a limitation. He said I should ask this if this is true or not.
Also our team tried to use Raspberry Pi 2 years ago and didn’t manage to put it in the robot because it consumed too much power. How are other teams using Raspberry Pi manage the power consumption?
Kauai Labs is working on getting our VMX-pi product (https://vmx-pi.kauailabs.com) working with RealSense. The big limitation is the RealSense wants a USB-C interface, which the Raspberry pi doesn’t have. So we are not there yet.
But, we anxiously await (fingers crossed) a RPI 4 that has a USB C interface!
The VMX-pi can now connect directly to the Power Dostribution Panel on a FRC robot and has a 3A power supply for the Raspberry Pi that should be able to power the RealSense.
But getting the RealSense data to RPI is the challenge. Take a look into that part of the puzzle.
We learned about RealSense from Greg McKaskle of National Instruments, He has been mentoring Team 2468 and might be a good contact on that sensor and have some ideas for you.
You need 2.4 Amps at 5V for Raspi 3 plus 0.7 Amps for realsense and you need to convert this directly from the robot battery or another 5V source. You can not plug the RasPi into the USB port of RoboRio. The problem also is that voltage at robot battery will drop low enough during full motor use that the RasPi might fail and reboot. One way to run RasPi is to use a battery pack of a phone charger or to add many capacitors to stabilize the 5 volt power supply. We used a 12v to 5V dc-dc converter and added large capacitors. We also used battery packs but for RasPi 4 as well as for RasPi 3 plus realsense camera you need to use USB-c type battery pack delivering at least 3 Amps at 5V. Micro USB is not made for 3 Amps but if you can get short usb cable with thick wires and it might work to deliver 3Amps. Dont use long and cheap USB cables. Get cables with small AWG numbers.
You can easily get away with using a raspberry pi on your robot. Many teams do this. What real sense camera are you referring to as some draw significantly more power than others. What applications are you planning of using the real sense in? I personally do not see any benefit of using the real sense in frc vision tracking applications.
R40. COTS USB battery packs with a capacity of 100Wh or less (20000mAh at 5V) and 2.5 Amp max output per port, or batteries integral to and part of a COTS computing device or self-contained camera (e.g. laptop batteries, GoPro style camera, etc.) may be used to power COTS computing devices and any peripheral COTS input or output devices connected to the COTS computing device provided they are:
A. securely fastened to the ROBOT.
B. connected only using unmodified COTS cables
C. charged according to manufacturer recommendations