Sensor Testing - OilSlick/coffee_tree_monitor GitHub Wiki

Testing the unit will be in phases. Currently I don't have all of the sensors available to test so I'm working with what I have, which can be considered the base sensor group that all units will include.

Phase 1 Testing

February 8, 2017 The current unit includes sensors to collect the following data:

• Light in Lux
• Barometric pressure in hPa (1 hPa = 1 mbar)
• Internal temperature of unit, in centigrade

All data is recorded every sixty seconds to both micro SD card and to Adafruit IO. To view the online graphs linked below, you will need a free Adafruit IO account.

• Lux Graph
• Temp Graph
• Pressure Graph

In addition to testing data logging and recording, I am also running a battery test to see how long the battery lasts on a full charge in the unit's current configuration.

Test Goals

1. Does it log locally?
2. Does it log online?
3. Is the data within acceptible limits (i.e. appropriate and useful)?
4. How long does the battery last?

Test Results

February 8, 2017

• Data from all three metrics is successfully being written and graphed online.
• Battery life still being measured (it's only been ~16 hours)
• Will verify SD logs are being written once the battery has died
• The TSL2561's peak reading is 17,000 Lux and that threshold is exceeded in full sun (a reading of 65,536 is an error message indicating a saturated sensor)
• The sensor is currently configured for "autorange" for gain and 402ms for integration time.
• With full exposure to the sun, the unit heats up significantly (51°C). Will need to test with differnt enclosure.

February 10, 2017

Battery test ended prematurely after 46 hours. Battery voltage at the end of the test was 3.46v. The current sketch can last at least two days without recharging the battery.

February 19, 2017

I tested the battery again in Galway, Ireland—this time leaving it outside overnight, where the temperature could drop into single digits; around 7-8°C.

These tests showed that the Li-ion battery loses a lot of capacity in the cold weather. None of my overnight tests lasted the full night, even on a full charge.