IoT Logitech Z906

The Logitech Z906 is a 5.1 THX-certified surround sound system. It is a powerful system with the ability to decode Dolby Digital and DTS-encoded soundtracks, but it lacks WiFi/network control.

Therefore, this project is a hardware and software solution that allows the unit to be controlled over the internet, adding smart WiFi control capabilities.

The Logitech Z906 usually cannot operate without the console connected, however, this solution removes the need for the console, replacing it with an ESP8266 control board.

The serial control logic for this project is based on the works of zarpli.

Hardware

To enable the control of the unit over the internet, an ESP8266 microcontroller was used which is a low-cost WiFi connected microcontroller.

The controller can be wired up to the console port or the Z906 using a rewirable DE-15 male plug, in order to make use of TTL serial communication at 3.3V.

Below is a circuit diagram that illustrates how to wire up an ESP8266 NodeMCU microcontroller to the console port.

Here is the pinout of a DE-15 male port (as viewed from the front).

The following pins from the Male DE-15 port should be wired to the ESP8266 in the following configuration:

DE-15 Pin	Description	ESP8266 Pin
3	GND	GND
6	GND	GND
11	3.3V @ 250mA	3V
12	TX	RX
13	RX	TX
15	Console Enable	GND

Finished Product

The connection between the Male DE-15 port and the ESP8266 should look something like this.

If using a rewirable plug, it should look something like this (with a few more cables!)

Software

Environment Variables

An environment variables file is included in the project.

An example of this file is provided in the repository (called example-environment.h). This file should be renamed to environment.h and populated in the project.

It contains specific configuration details for your project, including WiFi passwords.

To specify the network credentials you wish to use, the network credentials list can be modified in the environment.h file as follows:

const Wifi wifi_credentials[] = {
  { "YOUR_SSID_1", "YOUR_PASSWORD_1" },
  { "YOUR_SSID_2", "YOUR_PASSWORD_2" },
};

Control API

The project makes the following HTTP endpoints available to control all the functions of the Logitech Z906 over the API.

When making a web request to any of these endpoints, the microcontroller will run the desired action, interfacing with the Logitech Z906.

Endpoints

Endpoint	Parameters	Serial Command	Description
/input/1	-	SELECT_INPUT_1	Swap to the TRS 5.1 input
/input/2	-	SELECT_INPUT_2	Swap to the RCA 2.0 input
/input/3	-	SELECT_INPUT_3	Swap to the Optical 1 input
/input/4	-	SELECT_INPUT_4	Swap to the Optical 2 input
/input/5	-	SELECT_INPUT_5	Swap to the Coaxial input
/input/disable	-	BLOCK_INPUTS	Disable signal input
/input/enable	-	NO_BLOCK_INPUTS	Enable signal input
/volume/main	-	MAIN_LEVEL	Return the current Main Level
/volume/main/set	value: 0-255	MAIN_LEVEL	Set the Main Level to the parameter value
/volume/main/up	-	LEVEL_MAIN_UP	Increase Main Level by one unit
/volume/main/down	-	LEVEL_MAIN_DOWN	Decrease Main Level by one unit
/volume/subwoofer	-	SUB_LEVEL	Return the current Subwoofer Level
/volume/subwoofer/set	value: 0-255	SUB_LEVEL	Set the Subwoofer Level to the parameter value
/volume/subwoofer/up	-	LEVEL_SUB_UP	Increase Subwoofer Level by one unit
/volume/subwoofer/down	-	LEVEL_SUB_DOWN	Decrease Subwoofer Level by one unit
/volume/center	-	CENTER_LEVEL	Return the current Center Level
/volume/center/set	value: 0-255	CENTER_LEVEL	Set the Center Level to the parameter value
/volume/center/up	-	LEVEL_CENTER_UP	Increase Center Level by one unit
/volume/center/down	-	LEVEL_CENTER_DOWN	Decrease Subwoofer Level by one unit
/volume/rear	-	REAR_LEVEL	Return the current Rear Level
/volume/rear/set	value: 0-255	REAR_LEVEL	Set the Rear Level to the parameter value
/volume/rear/up	-	LEVEL_REAR_UP	Increase Rear Level by one unit
/volume/rear/down	-	LEVEL_REAR_DOWN	Decrease Rear Level by one unit
/input/decode/on	-	SELECT_EFFECT_51	Enable Decode Mode
/input/decode/off	-	DISABLE_EFFECT_51	Disable Decode Mode
/input/effect/3D	-	SELECT_EFFECT_3D	Enable 3D Effect in current input
/input/effect/4.1	-	SELECT_EFFECT_41	Enable 4.1 Effect in current input
/input/effect/2.1	-	SELECT_EFFECT_21	Enable 2.1 Effect in current input
/input/effect/off	-	SELECT_EFFECT_NO	Disable all Effects in current input
/save	-	EEPROM_SAVE	Save current settings to EEPROM*
/mute/on	-	MUTE_ON	Enable Mute
/mute/off	-	MUTE_OFF	Disable Mute
/temperature	-	GET_TEMP	Gets the system temperature
/version	-	VERSION	Gets the system firmware version
/power	-	STATUS_STBY	Get the current power status as a boolean
/power/on	-	PWM_ON	Turn the system on
/power/off	-	PWM_OFF	Turn the system off

*Please note, use the EEPROM_SAVE function with caution. Each EEPROM has a limited number of write cycles (~100,000) per address. If you write excessively to the EEPROM, you will reduce the lifespan.

Example Usage

The API can be called through any browser. For example:

GET /temperature should respond like this:

Useful requests also include:

• GET /volume/main/set?value=255 Sets the main volume to 100%.

Troubleshooting

1. Check your wiring and connections are correct.
2. Check your internet connectivity and WiFI credentials.
3. Check you have called /power/on and /input/enable and /mute/off and you're using the correct input.