Connect the STELLA-Q instrument according to these instructions: How the connectors work: The connectors on these components and cables are polarized, so you can only plug them together in the proper orientation. In photo SQ-C1, we see the metal of the connecting sockets in the cable. The other side of the connector, seen in SQ-C2, is solid. The solid side must face you when connecting to a board with a flat connector, as in SQ-C2 and SQ-C3. When connecting cables to vertical connectors, as in SQ-C4 and SQ-C5, the solid face of the cable connector faces the flat side of the board connector, while the exposed metal side of the cable connector faces the four exposed solder points on the circuit board. Connecting the components: Print the STELLA-Q flat layout drawing, at 100% scale on an 8.5 x 11" piece of paper. Lay the components on the layout drawing, as in photo SQ-A1. The square red components are the spectral sensors. Those sensors are marked on the back with a dot of black ink to indicate whether the sensor is responsive to visible light or to infrared light. The near infrared spectral sensor must be connected to Port 0 on the multiplexer, and the visible spectral sensor must be connected to Port 1. You can see the ink spot indicators in photo SQ-A3. In photo SQ-A2, we lay out the cables we will use to connect the components. SQ-A3 shows the components connected properly. It doesn't matter which device connects to any of the 5 ports on the hub, as the connections are all identical. Connect the power connectors as shown. They are also polarized, so you cannot connect them incorrectly. Safety Note: Never cut or strip wires that are attached to the battery, as shorting those wires together can start a battery fire. The key switches for the 1x4 keyboard plug into the switch contact points indicated in photo SQ-A4. Install all four switches, and then press four clear key caps onto the switches to make them more comfortable to press. You may wish to put a drop of glue on the center pin of each key where it contacts the circuit board, to stop the keys falling out. How to mount the components: Using velcro, or double stick foam tape, arrange the components on a flat stick, as shown in the completed instrument photos. The spectral sensors must point in the same direction, so they will observe the same spot at the same time. We generally mount the SHT40 air temperature sensor in the same direction, to put it in the shadow of the mounting stick, so it isn't heated by direct sunlight. The display and keyboard should point in the other direction, so that you can interact with the controls and readouts while pointing the sensors where you wish to. There is also an LED indicator on the top of the microcontroller, which should face you. That indicator will flash red when the instrument saves a datapoint to the datafile on the SD card. The indicator will glow continuously red to indicate a problem with the SD card, such as a missing card or a full card. With the two spectral sensors, we can make meaningful measurements of plant photosynthetic activity. To gather information about evapotranspiration, we need to measure the surface temperature of the leaf, which we can do remotely with a thermal infrared sensor. This sensor is not available already assembled to a connector, so if you want to add that capability to the STELLA instrument, find someone who can make four solder joints for you, as shown in SQ-A8 and SQ-A9, and connect it to the STELLA as shown in SQ-A10. It's important to get the four leads connected to the correct terminals on the adapter, and also important to get it to point perpendicular to the rear surface of the board, so it will point in the same direction as the spectral sensors. Finally, insert a CR1220 coin cell battery in the PCF8523 hardware clock module, according to the polarity marked on the battery and the battery holder, and insert a micro SD card into the slot on the back of the microcontroller. Push it in to seat it, push it again to eject it.