User guide
Set up the in-cabin sender, pair it with the engine-bay receiver, and control your first auxiliary output.
Before you begin
Disconnect vehicle power before wiring. AuxLink's receiver provides a logic-level control signal, not accessory load power. Use properly rated, fused switching hardware and consult a qualified automotive installer if you are unsure.
Wire the sender input
Connect a momentary switch between the sender input and ground. In the current hardware configuration, Auxiliary 1 uses GPIO4 with the ESP32's internal pull-up. Pressing the switch pulls the input low.
Connect the receiver output
Auxiliary 1 is an active-high logic output on receiver GPIO5. Connect it to a suitable relay, MOSFET, or driver circuit for the accessory—it is not a direct power output for a light bar or other high-current load.
Power both devices
On first startup, the sender broadcasts a pairing request and the receiver answers automatically. Keep the units powered near each other until both built-in RGB status LEDs change from flashing blue to solid green.
Test the control
Press the cabin switch once to turn Auxiliary 1 on, then press it again to turn it off. The receiver briefly flashes white when it applies the command. Confirm the driver circuit and accessory follow the expected state.
One press toggles the output
The sender debounces the switch and changes state only when the button is pressed. Both devices save the last on/off state. After a restart or reconnection, the sender sends its saved state to the receiver again.
If the receiver is offline, a switch press is ignored and does not change the saved state. Wait for both LEDs to return to solid green, then press the switch again.
Read the status LED
Dim white
Starting up
Flashing blue
Waiting to pair
Solid green
Paired and online
Slow flashing cyan
Saved peer is offline
Brief white
Command activity
Brief red
Communication or initialization error
Fast flashing violet
Software update in progress
Update from the receiver
With both paired devices powered, hold the receiver's maintenance button on GPIO6 for eight seconds. Join the Wi-Fi network beginning with AuxLink-Update- using password 123456789, then open http://192.168.4.1. Upload the single AuxLink update ZIP when instructed and keep both devices powered until they restart.
The sender updates first. The receiver installs its own image only after the sender restarts and reports the expected version.
View current release detailsCurrent firmware limitations
Version 1.5.1 defines one auxiliary channel. Pairing information is saved automatically, but the firmware does not currently provide a user-facing reset or re-pair control. Replacing either paired device requires clearing its saved ESP32 preferences or reflashing it.