Cognex Support Hub
Script - Saving Energy In Presentation Application
Controlling light illumination based on timer and ToF sensor
16.04.2025
Skip to Main Content
Controlling light illumination based on timer and ToF sensor
In the current hands-free application, there may be instances where we need to reduce the energy consumption of our solutions.
In such cases, we can use a script that monitors the period of inactivity beneath the reader and turns off the lights after a specified time. If something is detected under the reader, the lights will be turned on again. These scripts are designed to work with readers equipped with HPIT lights.
To implement this, two scripts are required:
Data Formatting Script:
'use strict';
const ENTER = '\x0D\x0A';
function onResult (decodeResults, readerProperties, output) {
if (decodeResults[0].decoded)
{
// Just output the code
output.content = decodeResults[0].content + ENTER;
if(serialHandler !== null){
// We use the serialHandeler (COM1) to start a timer. ENERGY_SAVING_TIME is defined in the COMMS Script
serialHandler.setTimer(ENERGY_SAVING_TIME);
}
}
}
Communication Script:
'use strict';
const LOG = true;
/* Energy saving parameters */
const ENERGY_SAVING_TIME = 300;// The time (in seconds) after a last scan when the energy saving should be enabled
const MIN_DISTANCE_MM = 50; // Min distance from HPIT where the operator should wave his hands to re-enable the readers
const MAX_DISTANCE_MM = 1200; // Max distance from HPIT where the operator should wave his hands to re-enable the readers
const POLL_TIME = 0.1; // Poll the distance sensor every x seconds to see if we need to re-enable the reader
const SECONDARY1_IP = '192.168.1.101'; // Specify address of possible secondary reader.
// Define the DMCC commands to be sent to the secondary (if any is present)
const DMCC_LIGHTS_ON = '||>SET LIGHT.DIRECT ON ON ON ON\r\n';
const DMCC_LIGHTS_OFF = '||>SET LIGHT.DIRECT OFF OFF OFF OFF\r\n';
const DMCC_AIMER_ON = '||>SET LIGHT.AIMER 1\r\n';
const DMCC_AIMER_OFF = '||>SET LIGHT.AIMER 0\r\n';
// variables to control the behaviour
let serialHandler = null;
let secondaryHandler = null;
let energySavingMode = false
function CommHandler (localName) {
return {
onConnect: function (peerName) {
if (peerName === 'COM1') {
serialHandler = this;
// Start the energy save timer since we also want to go out when we start up but don't read
serialHandler.setTimer(ENERGY_SAVING_TIME);
return true;
}
const peerIP = peerName.split(':')[0];
if (peerIP === SECONDARY1_IP) {
secondaryHandler = this;
logMsg('Secondary Reader 1 Connected');
return true;
}
return false;
},
onDisconnect: function () {
if(this === serialHandler){
serialHandler = null;
logMsg('Serial Handler Disconnected');
} else if (this === secondaryHandler) {
secondaryHandler = null;
logMsg('Secondary Reader 1 Disconnected');
}
},
onError: function (errorMsg) {},
onExpectedData: function (inputString) {},
onUnexpectedData: function (inputString) {},
onTimer: function () {
if (this === serialHandler){
if(energySavingMode === false){
enableEnergySaving();
serialHandler.setTimer(POLL_TIME);
} else if(energySavingMode == true){
// Check the distance and see if we have to re-enable
let currentDistance = dmccGet('HEIGHT-SENSOR.CURRENT-MEASUREMENT').response;
//logMsg('Current distance ' + currentDistance);
if(currentDistance >= MIN_DISTANCE_MM && currentDistance <= MAX_DISTANCE_MM){
// re-enable the lights
disableEnergySaving();
} else {
// we aren't allowed to disable the energy mode.. restart the timer to check again later
serialHandler.setTimer(POLL_TIME);
}
}
}
},
onEncoder: function () {}
};
}
function enableEnergySaving(){
// Turn of the Aimer and HPIT lights
dmccSet('LIGHT.AIMER' , 0)
dmccSet('LIGHT.DIRECT','OFF OFF OFF OFF');
energySavingMode = true;
// Also send the commands to the secondary (if connected)
if (secondaryHandler !== null) {
secondaryHandler.send(DMCC_AIMER_OFF);
secondaryHandler.send(DMCC_LIGHTS_OFF);
}
logMsg("In Energy Saving mode");
}
function disableEnergySaving(){
// Turn onn the Aimer and HPIT Lights.
dmccSet('LIGHT.AIMER' , 1)
dmccSet('LIGHT.DIRECT','ON ON ON ON');
// Also send the commands to the secondary (if connected)
if (secondaryHandler !== null) {
secondaryHandler.send(DMCC_AIMER_ON);
secondaryHandler.send(DMCC_LIGHTS_ON);
}
energySavingMode = false;
if(serialHandler !== null){
// Restart the timer since we have disaabled the energy mode
serialHandler.setTimer(ENERGY_SAVING_TIME);
}
logMsg("Disabled energy Saving mode");
}
function logMsg (msg) {
if (LOG) {
console.log(msg);
}
}