Controlling a HVAC Relay With a NodeJS Web Server and a Raspberry Pi

9 months ago
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HowTo nodejs raspberry pi hvac relay

In this video I control a HVAC relay using a Raspberry Pi and a NodeJS web server.

Prerequisite:
https://rumble.com/v4auyje-controlling-a-type-b-plug-with-a-hvac-relay-and-a-raspberry-pi.html

Run your server at start up:
https://rumble.com/v4ayapn-how-to-run-a-command-at-start-up-on-raspberry-pi-os.html

<code>
#!/home/william/.nvm/versions/node/v20.11.0/bin/node
const http = require('http');//require HTTP
const querystring = require('querystring');//require query string
const url = require('url');//require url
const { exec } = require("child_process");//require EXEC
http.createServer((req, res) => {//CREATE WEB SERVER
let runcommand = (command) => {//CREATE A FUNCTION THAT CAN BE CALLED TO RUN COMMANDS
exec(`${command}`, (error, stdout, stderr) => {
if (error) {///CONSOLE LOG ERRORS
console.log(`error: ${error.message}`);
return;
}
if (stderr) {
console.log(`stderr: ${stderr}`);
return;
}
});
}
let htmlMessage = '';//THIS VARIABLE WILL CONTAIN THE MESSAGE THAT WILL BE DISPLAYED TO THE USERS
let getValues = querystring.parse(url.parse(req.url).query);
if(getValues.onoff == "on")//IF /?onoff=on is sent then run the code in the if block that will call the runcommand function
{
runcommand('echo "The pin was turned on "`date` >> ./log');//THIS COMMAND WILL LOG THE ACTION TAKEN USING THE ECHO COMMAND
runcommand('./on.py');//THIS COMMAND WILL TURN ON THE GPIO PIN
htmlMessage = "<h1>The pin was turned on!</h1>";//THIS IS THE MESSAGE THAT WILL BE SENT TO THE USER
} else if(getValues.onoff == "off"){//IF /?onoff=off is sent then run the code in the if block that will call the runcommand function
runcommand('echo "The pin was turned off "`date` >> ./log');//LOG THE ACTION WITH THE ECHO COMMAND
runcommand('./off.py');//THIS COMMAND WILL TURN OFF THE GPIO PIN
htmlMessage = "<h1>The pin was turned off!</h1>";//THIS IS THE MESSAGE THAT WILL BE SENT TO THE USER
}
res.setHeader('Content-Type', 'text/html');//SET THE HEAD FOR HTML
res.writeHead(200, { 'Content-Type': 'text/html' });//WRITE THE HEAD
console.log(htmlMessage);
//BELOW IS THE SIMPLE HTML IT ONLY HAS TWO LINKS, A H1 ELEMENT AND A LITTLE CSS. THE LINKS WILL SEND THE GET INFO TO TURN ON AND OFF THE PINS
let html = `
<!DOCTYPE html>
<html>
<head>
<style>
a {
display: block;
padding: 10px;
margin: 10px;
size: 70px;
background-color: pink;
}
</style>
</head>
<body>
${htmlMessage}
<a href="?onoff=on">ON</a>
<a href="?onoff=off">OFF</a>
</body>
</html>
`;
res.write(html);//WRITE THE HTML
res.end();//END
}).listen(3000);

</code>

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