The child node comes in two configurations, the Mesh router and the Leaf node configuration, each share the same hardware with the firmware being the only difference. The child node connects directly or indirectly to the border router where the remote sensors and/or the control unit interfaces are located. The physical hardware is very simple and just needs the following parts: the IPM module, the sensors and units to control connected to the IPM module via a local PCB bus, a power source (typically a small battery), the PCB, an antenna (either an external antenna or a PCB antenna), and the enclosure (the mechanical box). This design is very simple to do for an electronics engineer with some hardware experience. If a PCB antenna is desired, then an RF designer also needs to be involved.