04 Hotspot Display Setup & Configruation
What is the role of the dvmhost_monitor?
- Display pertinent information on the I2C display attached to the MMDVM hat. Such information can include, but is not limited to:
- Connect status or network addresses of adapters such as eth0, wlan0, tun0
- FNE network addresses
- System Identity Name
- Site name
- Last message received details
- Radio ID
- Talkgroup ID
Prerequisites
- An Internet connect Raspberry Pi running Raspbian 12 (Bookworm) with a MMDVM hat flashed with the latest firmware from the DVMProject.
- This guide will assume it is a Raspberry Pi Model 3B+
- This guide will assume that there are no
iptablerules or other firewalls currently installed within Raspbian 12.
- The latest
dvmhost_monitorsource from GitHub. - A configured
dvmhostwith a validconfig.ymlthat associates with an FNE.
Connect to the Raspberry Pi & Download The dvmhost_monitor Release
cd /opt/dvm/
git clone https://github.com/DVMProject/dvmhost_monitor.gitInstall Node.js & NPM
sudo apt update
sudo apt install nodejs npm -yVerify the installation(s)
node -v
npm -vInstall I2C Bus Node.js Module
cd /opt/dvm/dvmhost_monitor/display/
sudo npm install i2c-busConfigure Raspberry Pi I2C Interface
sudo raspi-configEnable I2C
Within raspi-config, navigate using the arrow keys and enter key:
Interface Options → I2C → Yes (To Enable)
This step directly enables the I2C hardware interface on your Raspberry Pi, making it available for use by connected devices and software.
Verify I2C Device
ls /dev/i2c-1Update configuration in run.js
cd /opt/dvm/dvmhost_monitor/display/
nano run.jsThe run.js file contains the main script for the dvmhost_monitor and requires specific configuration updates for your environment. You'll need to edit this file to provide the correct paths and display names for your system.
Within run.js, locate and update the following variables:
const wlaninterface = 'wlan0';This line specifies the name of your wireless local area network (WLAN) interface. Common examples include wlan0. The monitor uses this to display WLAN-related information.
const ethinterface = 'eth0';This line specifies the name of your Ethernet interface. Common examples include eth0. The monitor uses this to display Ethernet-related information.
const vpninterface = 'tun0';This line specifies the name of your Virtual Private Network (VPN) interface. Common examples include tun0 or ppp0. The monitor uses this to display VPN connection status if applicable.
const sysName = ' NODE-NAME ';This line sets the display name for your system, which will be shown on the monitor's screen. Choose a descriptive name to easily identify your system.
Example run.js
/**
* Digital Voice Modem - Host Monitor
* GPLv2 Open Source. Use is subject to license terms.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* @package DVM / Host Monitor
*
*/
/*
* Copyright (C) 2022 Steven Jennison KD8RHO
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; version 2 of the License.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
// CONFIGURATION
// Location of dvmhost YML file
const ymlLocation = "/opt/dvm/config.yml";
// WLAN interface name
const wlaninterface = "wlan0";
// Ethernet interface name
const ethinterface = "eth0";
// VPN Interface name
const vpninterface = null;
// System name
// const sysName = centerLine("MY HOST");
/**
* DO NOT MODIFY BELOW THIS POINT
*/
const i2c = require('i2c-bus'),
i2cBus = i2c.openSync(1),
font = require('oled-font-5x7'),
yaml = require('js-yaml'),
fs = require('fs'),
readline = require('readline'),
rl = readline.createInterface({
input: process.stdin,
output: process.stdout,
terminal: false
});
var oled = oled = require('oled-i2c-bus');
class BigDecimal {
// Configuration: constants
static DECIMALS = 18; // number of decimals on all instances
static ROUNDED = true; // numbers are truncated (false) or rounded (true)
static SHIFT = BigInt("1" + "0".repeat(BigDecimal.DECIMALS)); // derived constant
constructor(value) {
if (value instanceof BigDecimal) return value;
let [ints, decis] = String(value).split(".").concat("");
this._n = BigInt(ints + decis.padEnd(BigDecimal.DECIMALS, "0")
.slice(0, BigDecimal.DECIMALS))
+ BigInt(BigDecimal.ROUNDED && decis[BigDecimal.DECIMALS] >= "5");
}
static fromBigInt(bigint) {
return Object.assign(Object.create(BigDecimal.prototype), { _n: bigint });
}
add(num) {
return BigDecimal.fromBigInt(this._n + new BigDecimal(num)._n);
}
subtract(num) {
return BigDecimal.fromBigInt(this._n - new BigDecimal(num)._n);
}
static _divRound(dividend, divisor) {
return BigDecimal.fromBigInt(dividend / divisor
+ (BigDecimal.ROUNDED ? dividend * 2n / divisor % 2n : 0n));
}
multiply(num) {
return BigDecimal._divRound(this._n * new BigDecimal(num)._n, BigDecimal.SHIFT);
}
divide(num) {
return BigDecimal._divRound(this._n * BigDecimal.SHIFT, new BigDecimal(num)._n);
}
toString() {
const s = this._n.toString().padStart(BigDecimal.DECIMALS+1, "0");
return s.slice(0, -BigDecimal.DECIMALS) + "." + s.slice(-BigDecimal.DECIMALS)
.replace(/\.?0+$/, "");
}
}
rl.on('line', function(line){
console.log("DVMHOST:" + line);
// [I: 2022-02-27 23:01:17.598 RX Frequency: 900974976Hz]
if(line.includes(" RX Frequency: "))
{
// [I: 2022-02-27 23:01:17.598 RX Frequency: 900974976Hz]
let frq = line.replace(/.*RX Frequency: /g,"");
// [900974976]
frq = frq.replace("Hz","");
// in Hz
// Round to clean up dvmhost interpretation
let tempNum = Math.round(frq/1000);
// Make bigdec
let frequency = new BigDecimal(tempNum);
// Divide by 1000 to get mhz
frequency = frequency.divide(1000);
// Ensure frequency is a string for manipulation
let freqString = frequency.toString();
// Check if there's a decimal point
if (freqString.indexOf('.') === -1) {
// No decimal point, so add .000
freqString += '.000';
} else {
// Decimal point exists, check how many digits are after it
const parts = freqString.split('.');
const decimalPart = parts[1] || ""; // Get the part after the decimal, or empty string if none
if (decimalPart.length === 0) {
freqString += '000'; // e.g., "123." becomes "123.000"
} else if (decimalPart.length === 1) {
freqString += '00'; // e.g., "123.4" becomes "123.400"
} else if (decimalPart.length === 2) {
freqString += '0'; // e.g., "123.45" becomes "123.450"
}
// If decimalPart.length is 3 or more, it already has enough decimal places.
}
//rxFrq = centerLine("R:"+frequency.toString()+" MHz");
rxFrq = centerLine("R: "+freqString.toString()+" MHz");
}
if(line.includes(" TX Frequency: "))
{
// [900974976Hz]
let frq = line.replace(/.*TX Frequency: /g,"");
// [900974976]
frq = frq.replace("Hz","");
// in Hz
// Round to clean up dvmhost interpretation
let tempNum = Math.round(frq/1000);
// Make bigdec
let frequency = new BigDecimal(tempNum);
// Divide by 1000 to get mhz
frequency = frequency.divide(1000);
// Ensure frequency is a string for manipulation
let freqString = frequency.toString();
// Check if there's a decimal point
if (freqString.indexOf('.') === -1) {
// No decimal point, so add .000
freqString += '.000';
} else {
// Decimal point exists, check how many digits are after it
const parts = freqString.split('.');
const decimalPart = parts[1] || ""; // Get the part after the decimal, or empty string if none
if (decimalPart.length === 0) {
freqString += '000'; // e.g., "123." becomes "123.000"
} else if (decimalPart.length === 1) {
freqString += '00'; // e.g., "123.4" becomes "123.400"
} else if (decimalPart.length === 2) {
freqString += '0'; // e.g., "123.45" becomes "123.450"
}
// If decimalPart.length is 3 or more, it already has enough decimal places.
}
//txFrq = centerLine("T:"+frequency.toString()+" MHz");
txFrq = centerLine("T: "+freqString.toString()+" MHz");
}
if(line.includes("(HOST) Host is up and running"))
{
controlStatus = true;
rptStatus = true;
}
if(line.includes("(NET) Connection to the master has timed out, retrying connection"))
{
LNK = false;
}
if(line.includes("(NET) Logged into the master successfully"))
{
LNK = true;
}
if(line.includes("P25 RF unit registration request from"))
{
var reg = line.replace(/.*from /g,"");
alertLn = centerLine(`R:${reg}`)
}
if(line.includes("P25 RF group affiliation request from "))
{
// 121501 to TG 50101
let data = line.replace(/.*from /g,"").split("to");
let unit = data[0].trim();
let tg = "TG"+data[1].replace("TG ","").trim();
alertLn = centerLine(`A:${unit}>${tg}`);
}
if(line.includes("P25 RF group grant request from "))
{
// 121501 to TG 50101
let data = line.replace(/.*from /g,"").split("to");
let unit = data[0].trim();
let tg = "TG"+data[1].replace("TG ","").trim();
alertLn = centerLine(`C:${unit}>${tg}`);
}
if(line.includes("P25 Net network voice transmission from "))
{
// 121501 to TG 50101
let data = line.replace(/.*from /g,"").split("to");
let unit = data[0].trim();
let tg = "TG"+data[1].replace("TG ","").trim();
alertLn = centerLine(`ID:${unit}>${tg}`);
}
})
var opts = {
width: 128,
height: 64,
address: 0x3C
};
oled = new oled(i2cBus, opts);
var statusLn1 = "NET:OK LNK:!! CC:!!"
var statusLn2 =[
" OFFLINE ", // [ CC lcn 00-0000 ]
" OFFLINE ", // [ MODE: P25T-CC ]
" OFFLINE ", // [ T:123.456mhz ]
" OFFLINE ", // [ R:123.456 ]
"WLAN OFFLINE ", // [WL:111.111.111.111 ]
"ETH OFFLINE ", // [ET:111.111.111.111 ]
"VPN OFFLINE " // [VP:111.111.111.111 ]
]
var alertLn = " ";
var siteName = ""
var rxFrq = "";
var txFrq = "";
var NET = false;
var LNK = false;
var control = false;
var controlStatus = false;
var rptStatus = false;
var FNE = "";
function getConfigData()
{
try {
const doc = yaml.load(fs.readFileSync(ymlLocation, 'utf8'));
return doc;
} catch (e) {
console.log(e);
}
}
var statusLineCurrent = 0
// Update Status Line
setInterval(()=>{
var newLine = "";
newLine+="NET:";
if(NET)
{
newLine+="OK";
}
else
{
newLine+="!!";
}
newLine+=" LNK:";
if(LNK)
{
newLine+="OK";
}
else
{
newLine+="!!";
}
if(control)
{
newLine+=" CC:";
if(controlStatus)
{
newLine+="OK";
}
else
{
newLine+="!!";
}
}
else
{
newLine+=" RPT:";
if(rptStatus)
{
newLine+="OK";
}
else
{
newLine+="!!";
}
}
statusLn1 = newLine;
},1000) // Dispay scroll speed in MS
function centerLine(name)
{
while(name.length<19)
{
name = " "+name;
if(name.length<19)
{
name=name+" ";
}
}
return name;
}
// Update LCN/Mode
setInterval(()=>{
let config = getConfigData();
let mode = "";
let status = "";
if(config.protocols.p25.enable && config.protocols.p25.control.enable && config.protocols.p25.control.dedicated)
{
mode = " MODE: P25T-CC ";
status = ` CC LCN ${config.system.config.channelId}-${config.system.config.channelNo} `;
control = true;
}
else if(config.protocols.dmr.enable && config.protocols.dmr.control.enable && config.protocols.dmr.control.dedicated)
{
mode = " MODE: DMRT-CC ";
status = ` CC LCN ${config.system.config.channelId}-${config.system.config.channelNo} `;
control = true;
}
else if(config.protocols.p25.enable && config.protocols.dmr.enable)
{
mode = " MODE: DMR/P25 VC ";
status = ` VC LCN ${config.system.config.channelId}-${config.system.config.channelNo} `;
}
else if(config.protocols.p25.enable)
{
mode = centerLine("MODE: P25");
status = centerLine(`CH ID: ${config.system.config.channelId} CH No: ${config.system.config.channelNo}`);
}
else if(config.protocols.dmr.enable)
{
mode = " MODE: DMR VC ";
status = ` VC LCN ${config.system.config.channelId}-${config.system.config.channelNo} `;
}
statusLn2[0] = status;
statusLn2[1] = mode;
statusLn2[2] = txFrq;
statusLn2[3] = rxFrq;
siteName = centerLine(`${config.system.config.rfssId}-${config.system.config.siteId} ${config.system.identity}`);
FNE = ` ${config.network.address}`
},5000)
// Update IP info
setInterval(()=>{
const { networkInterfaces } = require('os');
const nets = networkInterfaces();
const results = Object.create(null); // Or just '{}', an empty object
for (const name of Object.keys(nets)) {
for (const net of nets[name]) {
// Skip over non-IPv4 and internal (i.e. 127.0.0.1) addresses
if (net.family === 'IPv4' && !net.internal) {
if (!results[name]) {
results[name] = [];
}
results[name].push(net.address);
}
}
}
if(wlaninterface==null)
{
statusLn2[4] = centerLine(`${wlaninterface}: DISABLED`);
}
else
{
statusLn2[4] = centerLine(`${wlaninterface}: OFFLINE`);
try{
if(results[wlaninterface]!==undefined && results[wlaninterface].length>0) {
statusLn2[4] = centerLine(`${wlaninterface}: ${results[wlaninterface][0]}`);
}
}
catch {
//
}
}
if(ethinterface==null)
{
statusLn2[5] = centerLine(`${ethinterface}: DISABLED`);
}
else
{
statusLn2[5] = centerLine(`${ethinterface}: OFFLINE`);
try{
if(results[ethinterface]!==undefined && results[ethinterface].length>0) {
statusLn2[5] = centerLine(`${ethinterface}: ${results[ethinterface][0]}`);
}
}
catch {
//
}
}
if(vpninterface==null)
{
statusLn2[6] = centerLine(`VPN: DISABLED`);
}
else
{
statusLn2[6] = centerLine(`${vpninterface}: OFFLINE`);
try{
if(results[vpninterface]!==undefined && results[vpninterface].length>0) {
statusLn2[6] = centerLine(`${vpninterface}: ${results[vpninterface][0]}`);
}
}
catch {
//
}
}
require('dns').resolve('www.google.com', function(err) {
if (err) {
NET=false;
} else {
NET=true;
}
});
})
let inversion = 0;
let inverted = false;
setInterval(()=>{
inversion++;
if(inversion === 4)
{
inversion = 0;
inverted = !inverted;
oled.invertDisplay(inverted);
}
var status = "";
if(statusLineCurrent>statusLn2.length-1)
{
statusLineCurrent = 0;
}
if(alertLn.length>0)
{
status = statusLn2[statusLineCurrent];
}
statusLineCurrent++;
oled.clearDisplay();
oled.setCursor(1, 1);
oled.writeString(font, 1, `${statusLn1}`,1,false);
oled.drawLine(1, 8, 128, 8, 1);
oled.setCursor(1, 10);
oled.writeString(font, 1, `${status}`, 1, false);
//oled.setCursor(1, 20);
//oled.writeString(font, 1, ``, 1, false);
oled.setCursor(1, 30);
oled.writeString(font, 1, `${alertLn}`, 1, false);
//oled.setCursor(1, 30);
//oled.writeString(font, 1, `${siteName}`, 1, false);
oled.setCursor(1, 40);
oled.writeString(font, 1, `${siteName}`, 1, false);
oled.setCursor(1, 50);
oled.writeString(font, 1, `FNE:${FNE}`, 1, false);
},1000)My modified configuration makes some UI changes and introduces some additional code to make output look neater and more uniform. Notably, if you using frequency pairs that end in 000 such as 464.000 the script would originally display this as RX: 464. mhz. The code I added will display this as RX: 464.000 MHz. My configuration also adds an FNE variable and displays that at the very bottom of the screen. I made use of the centerLine() function as well to appease my brain so that when the details would scroll on the screen everything lined up nice and neat.
Verify configuration and launch dvmhost_monitor
sudo node run.jsConfigure the dvmhost_monitor to start at boot.
Open the System Cron Manager
sudo crontab -eAdd the @reboot entry.
- At the very end of the file append the following line. Ensure the paths referenced below match the paths on your Pi.
@reboot /usr/bin/journalctl -f -u dvmhost.service | /usr/bin/grep --line-buffered dvmhost | /usr/bin/node