# Add-on Modules The SMD family stands out for its modular, daisy-chained and rich electronics. Flexibility is as important as modularity, and 10 different types of add-on modules that can be connected in any order. All these different types of sensors ensure that the users have all the possibilities to turn their ideas into projects. ## ID Config All add-on modules have an **ID Config** part on their boards. The **ID Config** feature allows the system to handle more than one module of the same type. This feature comes in handy when the user wants to use up to 5 of the same module. For example, more than one Ultrasonic Distance Sensor Module or Reflectance Sensor Module can be used in mobile robots especially such as line following robots or object avoidance robots, in order to prevent collisions. The ID numbers are listed below the ID connector pins.

{% hint style="info" %} The ID of each module is "1" as default, even if there is no jumper on the ID Config area. {% endhint %} These pins can be connected in vertical doubles to select the desired ID for the module, with a 2 pin jumper. The name of the module will change as the ID changes, such as `Distance_3` for [Ultrasonic Distance Sensor Module](https://docs.acrome.net/electronics/add-on-modules/ultrasonic-distance-sensor-module) or `Light_5` for [Ambient Light Sensor Module](https://docs.acrome.net/electronics/add-on-modules/ambient-light-sensor-module). ## RJ-45 Connectors The RJ-45 connectors on add-on modules offer many possibilities for many scenarios. The RJ-45 cable can provide both power and data between SMD and add-on modules, it perfectly solves the cable tangle, solving two problems at once. RJ-45 connectors make it easy to connect add-on modules back to back. In addition, the click-lock feature keeps the connection secure both in terms of data and mechanically. The RJ-45 cables in the SMD product family are available in a variety of lengths. These are 7.5 cm, 20 cm and 35 cm RJ-45 cables. Different lengths provide different options for building a system. Also, RJ-45 cables are flat, making them easier to pass through any place. ## Input Add-on Modules Input sensors are the most important sensors when it comes to understanding and interacting with the environment. Input sensors are the majority in the world of sensors due to the need of continuous data collection and monitoring. Any kind of system can be controlled in a reasonable and stable way thanks to the input sensors. {% hint style="info" %} There are **7 input add-on modules** in the SMD family. {% endhint %}

	Cover image
Ambient Light Sensor Module	929c0b4e_1-ambient_light_sensor_module.webp	ambient-light-sensor-module
Button Module	3da4627b_1-button_module.webp	button-module
IMU Module	6465d672_1-imu_module.webp	imu-module
Potentiometer Module	c9c6e5ab_1-potentiometer_module.webp	potentiometer-module
Reflectance Sensor Module	Reflectance Sensor v3.png	reflectance-sensor-module
Ultrasonic Distance Sensor Module	6ac58fee_1-ultrasonic_distance_sensor_module.webp	ultrasonic-distance-sensor-module
Joystick Module	d154e609_1-joystick_module.webp	joystick-module

### Output Add-on Modules Output sensors are essential for physically interacting with the environment. They generally take a system input from the input sensors or an input created by the user through software. Any electronic device that has physically sensable outputs is an output sensor. {% hint style="info" %} There are **3 output add-on modules** in the SMD family. {% endhint %}

	Cover image
Buzzer Module	0e83f321_1-buzzer_module.webp	buzzer-module
RGB LED Module	9455d989_1-rgb_led_module.webp	rgb-led-module
Servo Module	522c44d3_1-servo_module.webp	servo-module

Due to the definition of output sensors, the 100 RPM brushless DC motor is also an output sensor, even though it is not an add-on module. {% content-ref url="../help/shops" %} [shops](https://docs.acrome.net/help/shops) {% endcontent-ref %} --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://docs.acrome.net/electronics/add-on-modules.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.