Operating instructions: When you turn on the STELLA-Q, it will boot in about 10 seconds. The keys will then light up; orange, yellow, green, and blue, and the display will show a 3 or 4 digit number. That number is the UID (unique identifier) for this specific microcontroller, so that every STELLA-Q will have different UID. To press the keys, you'll need to hold them down for a fraction of a second while the microcontroller gets around to checking the keys. The color light will go out, indicating that the program has seen that key and will respond accordingly. Press the orange key until its light goes out, and then let go. The display will show the hours and minutes set on the real time clock module. Those will be wrong until we set the time, so let's do that now: Look up the exact time and date, at https://time.is/UTC or equivalent. On the STELLA, hold down the orange key for a full two seconds. The display will show a UtC- message, that lets you know it's ready to set the date and time, and reminds you to set it to Coordinate Universal Time, usually known as UTC. Press and release the orange button, and the display will show the calendar year (YYYY). To set the year, press the yellow key. The display will flash, letting you know it is available to be set. The green key adds one, the blue key subtracts one. Press the yellow key when you are done setting the year, and the display will stop flashing. To skip to the next field, press the orange key. The fields all work the same. Press the orange key to select the field (year, month, day, day name, hour, minute, seconds). Press the yellow key to toggle between set (flashing) and check only (not flashing). When flashing, use the green key to add one to the value, and use the blue key to subtract one from the value. When you press the orange key after setting the seconds, the program stores the new date and time information to the real time clock, and the display shows the minutes and seconds, so you can check your setting against your reference clock. (MM:SS) Press the orange key, and again hold it a little until the light goes out. The display will show the version number for the STELLA-Q software. Press it again, and it will cycle between UID, current time in HH:MM, measurement batch number, and software version: UID HH:MM b xx v2.0.2 From any display message, press the yellow key to measure and record a single datapoint, containing the spectral and environmental measurements from the sensors. The instrument will update the batch number, so that you can associate a particular measurement with a particular observation. The measurements will be are recorded into a file called data.csv, on the SD card. Record observational descriptive data in a notebook or on a computer as the STELLA-Q is not equipped to record descriptive data. The batch number will increment by one, until the end of the calendar day, at which point the batch number will restart at 0. Batch 1, measuring the bare table. Batch 2, grass in direct sun. Batch 3, white reference card in direct sun. and so on. Perhaps you would like to take a bunch of measurements and average them. Press the green key to do that. It will count down from 3, and then take 20 measurements as fast as the instrument can. The display will show donE, and then show the batch number associated with those measurements. It will record all this information in a special file, one file for each time you activate the sample and average mode. You can change the number of measurements, and the countdown count and interval, in a file called STELLA_config.txt on the SD card. Maybe you prefer to take a long sequence of measurements, at a specific interval. Press the blue key to start a sequence, and press it again to stop. You can tell that the measurements are being recorded because the red LED on the microprocessor will flash each time data is recorded into the data.csv file. You can set the desired sample interval, in seconds, in the same STELLA_config.txt on the SD card. The instrument has a minimum interval of about 0.75 seconds, so set the interval to that value or to something longer. It's best practice to turn off the STELLA when removing the SD card, and leave it off until you have reinserted the SD card. If you forget to turn it off when you take out the card, turn it off before you put the card back in. Bringing up a fresh boot each time you install the SD card will help keep the file system stable.