3

FORGE

explanation is included with the complete sketch
at hsmag.cc/lDAiDE.

void watchForMessage() {

WiFiClient client = myserver.available();

if (client) {

while (client.connected()) {

if (client.available()) {

String req = client.readStringUntil(‘\r’);

client.flush()

if (req.indexOf(messageTag) != -1) {

value = 100.0/dashFSD *

dashCollectValue();

// using the coordinates create the web
page
client.println(“HTTP/1.1 200 OK”);
client.println(“Content-Type: text/html”);
......
}
}
}
}
}
The standard setup function calls the specific setup
functions for the serial monitor, the I^2 C interface,
the WiFi connection, the web server, and finally the
solar sensor.

void setup()

{

Serial.begin(115200); // used for testing

delay(10);

Wire.begin(SDA,SCL); // set up I2

startWIFI();

setupWebServer(); // start the web server

setup_solarirradiance(); //start solar sensor

}

The main control loop is very simple, just continually
calling the function watching for a request from a client
over the WiFi.

void loop()

{

watchForMessage();

}

The sketch, IOT-solarWeb.ino, contains additional
comments to aid understanding, and can be
downloaded from hsmag.cc/VmLxHn.

PUT ON THE SUNGLASSES
As the TLS2561 is designed for indoor use, it can be
overloaded in bright sunshine and a filter is required to

reduce the light falling on the sensor. PTFE is a good

filter material, as it reduces the light across all relevant

wavelengths uniformly. A cheap source of PTFE is the

tape used for sealing threaded joints by plumbers. This

tape is non-conducting, so it can be wrapped around

the module. The thickness of the tape is not always the

same, so it is difficult to be precise about how many

layers are required.

Set up the device and run the IOT-solarWeb.ino

sketch detailed above, as you add layers of tape. The

Serial Monitor in the Arduino IDE will display the raw

counts, while a client accesses the solar web server.

The maximum count returned is 65 535 and is returned

when the device is overloaded. Wrap layers round the

sensor to reduce the count in bright sunshine to less

than 32 000.

With the sensor mounted in its final configuration,

note the maximum count, Cmax, when it points directly

at the sun in a clear sky, around midday. The solar

irradiance under these conditions will be approximately

1000 W/m^2 , Imax. This value and the maximum reading

provide the calibration:

Imax / Cmax

This is used in the sketch so that output will be

in W/m2 and should be the value assigned to the

constant solcalib.

To see the solar dashboard, on a device connected to

the same WiFi network, type:

192.168.0.186/ESPsolar

...into the address box of a web browser. You should

now see the dashboard. The display will update

every second.

Above

A sensor mounted

outside, protected

by a glass cover