Weather Station with Light, Humidity, Temperature: More Data QA/QC

Test Components

Testing component:

The setup to test each component is simple. The photo below shows the tesing with 1kohm and different LDRs.

ldr test

The printout from Serial Monitor:

ldr reads

The LDRs at Pin 2 and 3 performed similarly.

Unexpectedly, some DS18B20 is not aligned with others. I have two batches of this sensor, one branded with DALLAS and one with 7Q-Tek. I did not compare against two brands. I picked two 7Q-Tek in the end.

ds18b20s

Ideally, with two sensors configuration, the test should be performed in every type of sensor. Next photo is to compare the reading of two TMP36 temperature with a more precision MCP9908.

readouts

Maintaining a precision 3.3V supply to TMP36 is the key. This outcome underlines one weakness of analog devices with ESP8266. It comes with low-capacity voltage regular than Arduino;s (AMS1117). Also, I decided to add a 3.3V voltage regulator to supply to other sensors and not share the load from 3.3V onboard.

ADS1115 ADC is a nice board expansion since it can cover the voltage change of an analog device from -6V to +6V. For analog devices with the change is much smaller voltage, ADS1115 can adapt to even a very small voltage change. The reading below is done with a potentiometer. The voltage readout is equal to the resolution (2mV with 1X gain). Other setting available on ADS1115 is 2/3X to 16X with each increment of the output number represents 0.1875mV down to 0.0078mV.

ads1115