Computing System Assembly - LoCO-AUV/loco_config GitHub Wiki

Raspberry Pi 4 and Pixhawk

The Raspberry Pi and Jetson physical assembly is pretty simple. First, you should make sure that your Raspberry Pi has any heatsinks you plan to use installed. We're currently using a small active fan that fits below the Pixhawk, but if you just want to use the passive aluminum heat sinks, that's fine too.

Other things that are recommended to have on your RPI before mounting it to your MDF are:

  • The MicroSD card. It's possible to remove it once mounted, but it is difficult.
  • The network adaptor (in the ethernet port).
  • The USB storage device, especially if you're using a thumb drive like us.

Once you've got the Pi's heatsinks all set up, it's time to mount the Pixhawk on top. We use a simple 3D printed part with velcro strips for this, as you can see here.

This leaves 2 mounting holes free to mount the RPI to the MDF, using M3x10 bolts and nuts, which is sufficient. At this point, the Pixhawk merely needs to be mounted to the RPI by the veclro strips.

Nvidia Jetson TX2

The Jeton's setup is slightly more difficult. Firstly, your Jetson needs to be removed from its dev board (assuming that you have one), attached to the Orbitty Carrier board, and have its fan cable plugged in. Additionally, make sure that you remove the WiFi antennae if you haven't by this point. It is a good idea to mount the Orbitty board properly using standoffs, but you can get by in the short term with just the GPIO (make sure you have standoff mountings in to stabilize everything before you actually put this in the robot). We attach the 3D printed mounting to the Orbitty (and therefore the Jetson) with M3x10's and hex standoffs, as can be seen in the below images.

It is important to attach any and all cables to the Jetson before mounting it on the MDF. The power cable and any GPIO cables (in our case serial cables for the OLED's microcontroller) will be inaccessible after mounting the Jetson to the MDF. Additionally, make sure that your SD card is in the Orbitty carrier board before mounting, as it's a bit of a pain to remove and insert after mounting.

The power cable is simply attached by the green screw-in terminals, visible in the bottom picture. Be careful not to reverse the polarity.