Observe with MCtoMQTT

MCtoMQTT reads packets from a USB-connected MeshCore radio and publishes them from an always-on Linux or macOS host.

Is this method right for you?

Use MCtoMQTT ifA Linux or macOS computer stays beside a packet-log radio connected over USB.

Use something else ifRemoteTerm, Home Assistant, or PyMC already manages the radio.

Keep onlineThe radio, USB connection, host service, and internet connection.

The helper can also configure meshcore-packet-capture for a companion connected by BLE, serial, or TCP.

Before you start

Requirement	Check
Radio	Packet logging works over USB and the local mesh settings are correct
Host	Linux or macOS for meshcoretomqtt; Windows is supported only for companion capture
Access	You can read the current config and restart the service
Location	A real three-letter location code
Tools	curl, a text viewer, and systemctl on Linux

Review before running

These helpers are not pinned to a release or checksum. Download and inspect them before running. --no-restart still writes files; it is not a dry run.

Files to review:

• Bash helper source
• Published Bash helper
• PowerShell companion helper source

What this changes

On a serial host, the helper:

• writes /etc/mctomqtt/config.d/20-meshcore-ca.toml;
• makes a timestamped .bak.<timestamp> copy when that file exists;
• adds the primary and backup MeshCore Canada endpoints and location code; and
• restarts mctomqtt unless --no-restart is used.

For companion capture, it updates ~/.meshcore-packet-capture/.env.local, makes a timestamped backup, configures slots 1 and 2, disables slots 3–6, and may restart the capture service.

Install flags download and run separate upstream installers. Do not use them until you have reviewed the named upstream installer too.

Set up

1. Download and inspect the helper

workdir="$(mktemp -d)"
curl -fsSLo "$workdir/add-meshcore-ca-broker.sh" https://meshcore.ca/analyzer/scripts/add-meshcore-ca-broker.sh
less "$workdir/add-meshcore-ca-broker.sh"

Check the source URL, changed paths, endpoint hosts, backup behaviour, and restart behaviour. Keep the file for the rest of this setup.

2. Write without restarting

Replace YOW with the real location code nearest the observer:

bash "$workdir/add-meshcore-ca-broker.sh" --device serial-host --iata YOW --no-restart

The helper validates the code shape, rejects XXX, warns on codes outside its quick list, and prints the changed and backup paths.

3. Review the result

sudo sed -n '1,220p' /etc/mctomqtt/config.d/20-meshcore-ca.toml

Check that:

• the location code is correct;
• primary host and audience are mqtt1.meshcore.ca;
• backup host and audience are mqtt2.meshcore.ca;
• port is 443, transport is WebSockets, and TLS verification is enabled.

Do not paste the full file into a public issue without reviewing it.

4. Restart deliberately

sudo systemctl restart mctomqtt
sudo systemctl status mctomqtt --no-pager

The service should stay active without repeated TLS or authentication errors.

Run it directly after review

After reviewing the current published helper, you can run that same file directly:

bash <(curl -fsSL https://meshcore.ca/analyzer/scripts/add-meshcore-ca-broker.sh) --device serial-host --iata YOW

The downloaded-file method above is easier to review and recover.

Fresh installation

--install-mctomqtt downloads and runs the upstream meshcoretomqtt installer. Review that installer first, then add the flag:

bash "$workdir/add-meshcore-ca-broker.sh" --device serial-host --iata YOW --install-mctomqtt

The upstream installer controls serial-port selection and package changes, and it is not pinned or checksummed here.

Companion capture

Set the companion radio to the local mesh settings first.

Linux or macOSWindows PowerShell

Review the same Bash helper, then run:

bash "$workdir/add-meshcore-ca-broker.sh" --device companion --iata YOW --no-restart

Review ~/.meshcore-packet-capture/.env.local, then restart your capture process.

Download and inspect the helper before running:

$helper = Join-Path $env:TEMP "add-meshcore-ca-packetcapture-broker.ps1"
Invoke-WebRequest https://meshcore.ca/analyzer/scripts/add-meshcore-ca-packetcapture-broker.ps1 -OutFile $helper
Get-Content $helper
powershell -NoProfile -ExecutionPolicy Bypass -File $helper -Iata YOW

The PowerShell helper changes %USERPROFILE%\.meshcore-packet-capture\.env.local and creates a backup. Its optional install switch executes an upstream installer and must be reviewed first.

There is no documented meshcoretomqtt Windows installer for the packet-log serial-host path.

What you should see

The service stays active, the primary endpoint connects, and its packet count changes when the radio hears nearby traffic.

Verify in CoreScope

1. Confirm the service remains active.
2. Find the observer in CoreScope Observers.
3. Wait for normal nearby activity.
4. Confirm a recent packet in CoreScope Packets.

Finish with Check your observer. A running service or broker connection is not proof that packets reached CoreScope.

Recovery

Use the exact backup path printed by the helper.

If a serial-host drop-in existed before:

sudo cp -- '/etc/mctomqtt/config.d/20-meshcore-ca.toml.bak.<timestamp>' '/etc/mctomqtt/config.d/20-meshcore-ca.toml'
sudo systemctl restart mctomqtt

If the helper created a new drop-in and no prior file existed:

sudo rm -- '/etc/mctomqtt/config.d/20-meshcore-ca.toml'
sudo systemctl restart mctomqtt

For companion capture, restore the printed .env.local.bak.<timestamp> over .env.local, preserve its permissions, and restart the capture process.

The helper does not uninstall software added by an upstream install flag. Use that upstream project's reviewed uninstall process.

If verification fails

Use Troubleshooting. Share only a short redacted service status and the list of changed paths.