The LED Controller example application controls up to two 3W RGB LEDs. Using the LED Controller application, you can control each LED directly or via the IzoT network using the demo Web pages, as shown in the LED Control Web page.  You can turn each LED on or off, dim each LED if it supports dimming, and set the color of each LED that supports color.

The LED Controller example application also supports up to two pressure sensors. Each corresponds to one of the two LEDs (sensor 1 to LED 1, sensor 2 to LED 2), and reads a pressure value from a hardware FSR sensor; when the detected pressure is over a given limit (configurable in the source code).  The corresponding LED brightness is dimmed up/down continuously. To stop dimming, let go of the pressure sensor. The pressure sensor value is not shared over the IzoT network.

While running the LED Controller offers a connection target for the first LED on the LED Controller that Keypad devices can use to create keypad to LED connections.

In a typical demo setup, each LED will be controlled in both brightness and (if an RGB led) color by the keypad script (see Touch Keypad) over the network from the Web pages, and optionally in brightness only by the corresponding local pressure sensor.

This section consists of the following:

Hardware

The led.py script will work with the following hardware:

1x Raspberry Pi (Rev.2)

1x Adafruit 16-Channel 12-bit PWM/Servo Driver - I2C interface - PCA9685 (https://www.adafruit.com/products/815)  to control the PMW LEDs (the Pi itself does not have enough PWM channels)

2x Star Controller - 3 Watt RGB Star LED Controller Kit with PWM input (https://solarbotics.com/product/60160/) to be used as main controlled LEDs

2x Round Force-Sensitive Resistor (FSR) - Interlink 402 (https://www.adafruit.com/products/166) to generate the pressure value that will be used to control the brightness of the LEDs

2x Simple PWM RGB LEDs (Adafruit 139) to be used as Connect lights

2x Pushbuttons to be used as Connect buttons

The schematics are available in Eagle and PDF format in the hardware directory within the LED Controller example directory.

Running the LED Controller Application

You can start the LED Controller example application as a service and optionally enable it to automatically run on boot, or you can run it from the command line. Running from the command line is useful for doing interactive testing and debugging. Running as a service is useful for setting up working networks and demonstrations.

To start the LED Controller example application as a service and enable it to run on boot, enter the following command:

izot_enable led

To stop the LED Controller example application and disable it from running on boot, enter the following command:

izot_disable led

To start the LED Controller example application without changing its boot status, enter the following command:

izot_start led

To stop the LED Controller example application without changing its boot status, enter the following command:

izot_stop led

To display the status of all IzoT services, enter the following command.

izot_stat

To run the LED Controller example application from the command line, change to the LED Controller example directory at $IZOT/izot/examples/led_controller and enter the following command at the Linux shell prompt:

supy led.py [-C] [-D] [-d DEVICE] [-h] [-I] [-i] [-L LED_TYPE] [-l LOG] [-m] [-N SCENES] [-n NVD] [-pPROGRAM_ID] [-s SENSOR] [-v] [-r RESET_TYPE]

The following table summarizes the command-line flags and options: