• Adafruit IR Break Beam

    Tony Kambourakis02/15/2016 at 01:19 2 comments

    The Adafruit IR Break Beam sensor comprises two components; an emitter that generates an IR beam and a receiver that is sensitive to the IR beam. When the beam from the emitter is broken the receiver pulls its digital output low. The receiver's digital output is open collector therefore the input mode for D4 and D6 were set to INPUT_PULLUP to keep them normally high.

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  • DFRobot Digital Vibration Sensor V2

    Tony Kambourakis02/07/2016 at 14:26 1 comment

    The DFRobot Vibration Sensor uses the same type of coil mechanism inside to detect vibration. This sensor has a normally-high digital output which goes low during a vibration. I took the MCU with the sensor out for a field test with my letterbox. An LED was wired to switch on when a vibration was detected. Whilst knocks and taps were detected, inserting letters and pamphlets into the top tray did not cause a strong enough vibration to be detected by the sensor. Power was supplied by 2xAA batteries.

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  • Migrating to Platform.io IDE (Atom)

    Tony Kambourakis01/31/2016 at 01:08 0 comments

    More structured details to come. Some quick notes:

    • Copy the original Arduino .ino file to Platform.io IDE on Atom may cause build issues. Create a new .ino file using PIO IDE and then copy/paste source code from Arduino .ino file to new .ino file.
    • The packet size of the MQTT client needed to be increased from 128 to 256. This is in the PubSubClient.h header file located in .pioenvs/nodemcu/PubSubClient_ID89
    • The following libraries were added:
      • 19 Adafruit-DHT
      • 89 PubSubClient

  • Vibration Switch

    Tony Kambourakis01/08/2016 at 01:12 1 comment

    Tried the Adafruit vibration switch (purchased from Core Electronics) to see if it can be used to detect the insertion of a letter/package in the letterbox. It comprises a metal pin with a soft spring coiled around it. When it is moved the coil touches onto the pin, essentially behaving as a switch.

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