How-To: Stack multiple ODROID-N2(+) Units for a Cluster
We had a customer write in and ask if it was possible to stack ODROID-N2+ units. We were pretty sure it was possible, but we thought we'd give it a shot to see how difficult it was.
There are four Phillips screws holding the N2+ mainboard to the N2 heatsink. Remove these and replace them with an M3 post, one at a time, to avoid getting the holes out of alignment or smearing the thermal paste between the mainboard and the heatsink.
There are two main methods. Both methods require M3 standoffs something like the standoff pictured to the right, but with a longer threaded end. If you're only mounting two on top of each other, like in the pictures below, you won't need the longer threaded end as it doesn't have to extend through and below the heatsink.
Cluster with Aligned Ports
The first method lines all the ports on the same side of the cluster, but requires a little more vertical space to do so.
For this method, we recommend a minimum of 22mm posts with a minimum of 12mm M3 threaded male end. Using these posts, you can make your cluster contain as many N2+ units as you'd like.
Cluster with Interlaced Port Orientation
The second method alternates which side the ports are facing (front/back) which allows shorter posts to be used for an overall shorter height.
For this method, we recommend a minimum of 15mm posts with a 12mm M3 threaded male end. Using these posts, you can make your cluster contain as many N2+ units as you'd like, and with a lower overall height than the above method.
For either method, we recommend a minimum of a 12mm M3 bolt to hold the top unit to the stack, unless you're happy using more standoffs as with the lower units.
3D Printed Method
If you want to create a cluster without any special screws, a 3D printed vertical plate at the back corners could be designed to allow the existing screws to hold the vertical plate in place. A simple spacer could be used to hold the front sides at the right distance from each other.
Of course, with 3D printing, the sky's the limit on what you can design.