The lidar ordered came in and it seems to be in working order, I think the bearings are going out but it should suffice for testing and getting the ROS navigation stack up and running. That is what you get buying used sometimes. ROS itself also requires a IMU so I have one on the the way that is compatible. It's funny I'm big into lower level electronics, but the time saved just ordering a module is so worth it sometimes.  I'm a bit stuck with ROS melodic at the moment as it is tied to the Jetson TX2. I have however been looking at the NVIDIA Jetson Orin Nano Developer Kit as a upgrade once the robots mechanical is finished.

List of current sensors -

Zed Stereo camera v1, This has the ability to give a distance point map and up to this point I have not utilized the distance feature yet. The following list is expected uses. 

1. Have the head tilt down a few degrees during a move command so that it can detect obstacles the lidar does not catch and fall hazards. 
2. Measure distance to wall when playing hide and seek this is so it can head to the wall and face it when starting to count. (like it is not looking)
3. Measure the distance of a book held in front of it. 
4. Measure the approximate size and figure out a good grip for a unknown object that the robot will attempt to pick up. 
5. Inference from Chat GPT vision (when entering a large room or unknown location)
6. Allows for face and object detection
7. Taking pictures

hfi-a9 IMU - needed for the navigation stack (Gyroscope Accelerometer Magnetometer 9 Axis). 

Seed studio Respeaker v2 - A x4 microphone array with on-board noise canceling and DOA (direction of arrival)

1. Used for offline and online voice assist. 
2. Will use to "cheat" playing hide and seek (what is the purpose of a directionally based mic array if you can use it to travel in the rough direction of noise)
3. Turn and face a active talker

HOKUYO UST-10LX - a powerful scanning lidar again used for navigation and detecting objects, also helps the main computer create a map of the environment. 

AM2315C - Encased I2C - a enclosed temperature/humidity Sensor this will enable the robot to tell the user the indoor air, so user can ask (what is the current temperature inside... so on)

Linear actuator potentiometer - used to tell where the arm is at and will allow for the robot to place it at different heights instead of just down and up. 

Current and voltage sensors - these will be used to tell the main battery packs voltage and current draw. Will allow a time remaining and when the robot needs to go look for power/charge. 

IR break sensor - in the custom gripper there is a IR break sensor to detect objects entering/leaving the grip. (old school but still helps)

Possible more but this should cover a good portion of what the robot is intended to do.