Finding the MAC address of your module

Thu, 10 Sep 2026 00:00:00 +0000

What is a MAC?

Every wireless device has a MAC address. It is a unique code set at the factory. You can think of it as the device’s serial number for wireless communication.

A MAC address is 12 characters long. It is usually written in pairs separated by colons, for example:

34:85:18:A1:2B:3C

It only ever contains the numbers 0 to 9 and the letters A to F.

Why does HandShake need it?

The watch and the receiver each need to know the other’s MAC address:

The watch needs the receiver’s MAC address so it knows where to send its signals.
The receiver needs the watch’s MAC address so it knows which watch to listen to. It will then ignore every other watch.

This matters when several people use HandShake in the same room. Each watch talks only to its own receiver and each receiver responds only to its own watch.

How to find the MAC addresses

You need two MAC addresses: one for the watch and one for the receiver. You can read both using a free website called ESPConnect. Nothing needs to be installed.

You will need:

A computer running Google Chrome or Microsoft Edge. Other browsers such as Firefox and Safari will not work.
A USB-C cable that carries data. Some cables only charge. If the device doesn’t appear in step 4, try a different cable.

Steps:

Follow these steps for the watch, then repeat them for the receiver.

Connect the device to the computer with the USB cable.
Open Chrome or Edge and go to https://thelastoutpostworkshop.github.io/ESPConnect/
Click Connect.
A box will pop up asking you to choose a device. Select the device. It is usually listed as USB JTAG/serial debug unit. Then click Connect in the box.
Wait a few seconds for the page to finish connecting.
Open the Device Info tab. The MAC address is shown in the summary.
Write the MAC address down and label it clearly as watch or receiver.
Click Disconnect and unplug the device.

If the device doesn’t start normally after unplugging, turn it off and on again.

Tips for entering the MAC addresses

Don’t swap them. The watch is given the receiver’s address. The receiver is given the watch’s address.
Copy each address carefully, one pair at a time.
Watch out for characters that look alike. A MAC address never contains the letter O, so it is always the number zero. The same goes for I and L, which are always the number 1.
Check that you haven’t mixed up 8 and B.
Capital or lower-case letters make no difference.

If the watch and receiver don’t connect, a mistyped or swapped MAC address is the most likely cause. Check both addresses character by character before trying anything else.

Mac on HandShakeTec

Finding the MAC address of your module

What is a MAC?

Why does HandShake need it?

How to find the MAC addresses

Tips for entering the MAC addresses