Latest Version: 1.0.0
The Si114x is an I²C proximity, UV and ambient light sensor. The Si114x library can be used with the Si1145, Si1146 and Si1147.
The Si114x interfaces over I²C, and works best with the clock rate set at CLOCK_SPEED_100_KHZ or CLOCK_SPEED_400_KHZ. If lower clock rates are used, you may need to add an imp.sleep() at the beginning of your forceRead() callbacks.
You can view the library’s source code on GitHub. Click here to see information on other versions of this library.
To add this library to your project, add #require "Si114x.class.nut:1.0.0" to the top of your device code.
The class’ constructor takes one required parameter (a configured imp I²C bus) and an optional parameter (the I²C address of the sensor):
| Parameter | Type | Default | Description |
|---|---|---|---|
| i2c | hardware.i2c | N/A | A pre-configured I²C bus |
| addr | byte | 0xC0 | The 8-bit I²C address of the sensor |
For example:
#require "Si114x.class.nut:1.0.0"
i2c <- hardware.i2c89;
i2c.configure(CLOCK_SPEED_400_KHZ);
als <- Si114x(i2c);
Enables (state = true) or disable (state = false) the ambient light sensor. You must enable the ambient light sensor before calling getALS() or forceReadALS()
als.enableALS(true);
Enables (state = true) or disable (state = false) the proximity sensor. You must enable the proximity sensor before calling getProximity() or forceReadProximity().
als.enableProximity(true);
Sets the data rate for the ALS and proximity sensor (how often the device wakes up and takes a reading). Settings dataRateHz to 0 will disable autonomous mode (the device will only take readings by calling forceReadALS() or forceReadProximity()).
Note Not all data rates are available and the setDataRate() method will return the actual data rate set.
// Collect data 10 times per second
local dataRate = als.setDataRate(10);
server.log("Data rate: " + dataRate);
Returns the actual data rate set in Hertz.
server.log("Data Rate: " + als.getDataRate() + " Hz");
Collects the most recent data from the ALS sensor and invokes the callback with a single parameter: a table containing the following keys:
| Key | Type | Description |
|---|---|---|
| visible | Integer | The visible light (in lux) |
| ir | Integer | The IR light (in lux) |
| uv | Float | The UV Index |
Note The uv value is returned as a UV index between 0 and 11.
Before calling getALS() you should pass true to enableALS() and call setDataRate() with a non-zero data rate.
als.enableALS(true);
als.setDataRate(2); // 2Hz
// Poll the ALS data every second
function poll() {
imp.wakeup(1, poll);
als.getALS(function(data) {
server.log("Visible: " + data.visible);
server.log("IR Light: " + data.ir);
server.log("UV Index: " + data.uv);
});
}
poll();
Collects the most recent data from the proximity sensor and invokes the callback with a single parameter: a table containing a single keys, proximity. This is an integer in the range 0—65535. The higher the proximity value, the closer the ranged object.
Before calling getProximity() you should pass true to enableProximity() and call setDataRate() with a non-zero data rate.
als.enableProximity(true);
als.setDataRate(2); // 2Hz
// Poll the ALS data every second
function poll() {
imp.wakeup(1, poll);
als.getProximity(function(data) {
server.log("Proximity: " + data.proximity);
});
}
poll();
The forceReadALS() method forces the IC to update the ALS sensor information and invoke the passed callback function when complete. The callback is invoked with the same table as getALSData().
Before calling forceReadALS you should should pass true to enableALS().
als.enableALS(true);
// Get a 1-shot reading
als.forceReadALS(function(data) {
server.log("Visible: " + data.visible);
server.log("IR Light: " + data.ir);
server.log("UV Index: " + data.uv);
});
The forceReadProximity method forces the IC to update the proximity sensor information and invoke the passed callback function when complete. The callback is invoked with the same table as getProximity().
Before calling forceReadProximity you should should pass true to enableProximity().
als.enableProximity(true);
// Get a 1-shot reading
als.forceReadProximity(function(data) {
server.log("Proximity: " + data.proximity);
});
The Si114x can generate interrupts whenever new data is available from the ALS and/or proximity sensor. The configureDataReadyInterrupt() method allows you to enable (state = true) or disable (state = false) the data-ready interrupt, as well as select what data should trigger the interrupt. To specify what channels to enable the data-ready interrupts on, you can generate a bit field with either or both the Si114x.DRDY_ALS (for new ALS data) and Si114x.DRDY_PROXIMITY constants.
als.setDataRate(2); // 2 Hz
als.enableALS(true);
als.enableProximity(true);
als.configureDataReadyInterrupt(true, Si114x.DRDY_ALS | Si114x.DRDY_PROXIMITY);
alsInt <- hardware.pinD;
alsInt.configure(DIGITAL_IN, function() {
if (alsInt.read() == 1) return;
local state = als.getInterruptTable();
if (state.als) {
als.getALS(function(data) {
server.log("Visible: " + data.visible);
server.log("IR: " + data.ir);
server.log("UV: " + data.uv);
});
}
if (state.proximity) {
als.getProximity(function(data) {
server.log("Proximity: " + data.proximity);
});
}
});
The getInterruptTable() method reads and clears the interrupt source register and returns a table with the following keys:
| Key | Type | Description |
|---|---|---|
| als | Bool | True if new ALS data is available |
| proximity | Bool | True if new proximity data is available |
See configureDataReadyInterrupts() for sample usage.
The Electric Imp Dev Center documents the latest version of the library. For past versions, please see the Electric Imp public GitHub repos listed below.
| Version | Source Code | Notes |
|---|---|---|
| 1.0.0 | GitHub | Initial release |
The Si114x class is licensed under MIT License.