We’ve just received our Jetson Nano Devkits and are now busy setting up the devices. Doing so I inevitably ran into some hordes to overcome, and I thought to give some feedback or help others out it would be nice to write my experiences on this forum.
- Power supply
There are already numerous topics regarding this topic, so I think Nvidia has some lessons to be learned there ;). Anyways, when wanting to use the DC barrel jack, don’t forget to place a jumper on J48 (beside the camera input connector)!
My first thought was, why does the board need a 5V supply and no range like 5~9V is defined? Then I looked at the board and saw they simply haven’t had/made room available to design a proper DC/DC supply. So, I guess, the 5V you connect at the power inputs simply goes straight to the components that need it, which indeed don’t allow a wide input range.
I wanted some length on the cable to be able to move around the Nano on my desk a bit, so I used a voltage drop calculator to calculate what type of wire I would need for approx. 2 meters in length. I remember reading somewhere on the forums that 4,75V is the absolute minimum, so I took that as a parameter to decide the wire size (AWG) needed. I ended up using 2 meters of 2x1,5mm² (15AWG). This gives a negligible drop to 4,83V at the rated maximum current of 4A.
Next up is the connector. This makes things tricky, as the size of the DC barrel simply barely fits thick wires like the 1,5mm². I ended up using this connector, which gives some room to separate/isolate the plus from the minus with some heat shrinking tube. I did have to bore out the back side a bit to make 2x1,5mm² fit through.
Finally the power supply itself. Nvidia recommends a power supply from Adafruit, but that beeing an American company concludes to quite high shipping costs to here in the EU. For now I’m using the benchtop power supplies we use at work anyways, but I also bought a Nano for private use and I’m still on the search for a proper, efficient power supply at a reasonable price. I will update on this when I’ve found one.
- Cooling fan
Although I haven’t fully used the board yet, it’s always better for a device to remain cool. Nvidia advises the uses of the good quality yet pricey Noctua NF-A4x20-PWM. On the search for a 5V 40x40cm fan I quickly found at that there is quite a variety available, but very little with a 4-wire PWM connection. I did find one at Mouser, but it isn’t much cheaper anyway. Please also note that you need to buy self-tapping M3 screws with enough length to go through your fan and the holes in the heat sink.
- First power up
After flashing the SD-card I could finally power up the board. As I didn’t have a spare monitor, I was starting it headless. First thing I noted, the ethernet LED’s aren’t blinking…? But I did see LED’s blinking at my switch, so I assume the board did indeed power up. This started me looking for a MAC-address to trace the device on our network, but I found out that the Nano devkit doesn’t have a MAC-address sticker as the TX2 devkit has. Eventually it was easier to hook up a monitor, after which I was able to find the IP address through the GUI.
However, the ethernet LED’s still aren’t blinking on the devkit itself, so don’t mistake this for a non-functioning device!
That’s it for now, we’ll probably run into some more things later on :)