Normally, client computers and devices receive their addresses from Open-Mesh nodes via DHCP.  But in some cases, such as with wireless printers or cameras, it can be helpful to use a static IP address.

This can be done, but currently requires setting a unique SSID for each node in your mesh network.

On the dashboard, uncheck "AP Isolation" on the advanced tab, and select "Use Node Name" on the SSID#1 tab.  This will let you associate the camera or other wireless device with a given node.  Associate your wireless device with the SSID of the closest node to it.

Then, look at the IP address for that node on the "network status" page of the dashboard.

The IP a node will issue to client devices is 101.x.y.n where x,y are the last two quads of the node's IP.  So, if the node has IP 5.88.99.168, it will issue client computers addresses in the range 101.99.168.n, where n is 10 and up.

So, you can use IPs 2-9 for static devices. 

For your device in the above example, you could set it up as:

IP:  101.99.168.5

MASK: 255.255.255.0

Default Gateway:  101.99.168.1

DNS:  101.99.168.1