Users' guide to Hardware

Hardware Requirements

This list does not account for the material already in AutoMec’s inventory. Please bring with you:

Laptop
Laptop charger
Smartphone with ROS Mobile installed or video-game controller

Accessing EDUROAM

To access the university's network, you can use your GUI and copy the following configurations:

On username and password, please input your university's e-mail and respective password.

Turning the car ON

Connect the battery to the car
Turn on the ESC
Verify if the micro-controller connections are correct
Connecting the micro-controller to the laptop
Connect the RGBD camera to the power-bank and press the powerbank button
Connect all cameras to the laptop

Common errors:

The battery is out of charge, you can check the battery using the external battery checker.

Manual Control

To manually control the car, there are two different options. You can use your smartphone or a video-came controller.

Smartphone Setup

Step 1

To drive the car, the laptop and the smartphone need to be connected to the same WiFi network. It is more practical to create an hotspot on the smartphone and accessing that same network from the laptop.

Step 2

To set up ROS-Mobile:

In the Master page, place the laptop's local IP address on the Master URL space. If you don't know your local IP address, type hostname -I to your terminal
Place the port 11311 in the Master port space

If it isn't successful you can try port forwarding. For this you need to allow port 11311 through your firewall, to do this run the following command in the terminal:

sudo ufw allow 11311

Set up widgets:

For controlling the velocity and steer use a joystick with the topic /cmd_vel and the type geometry_msgs/Twist. The axis x controls the velocity and the axis y controls the steering.

In the end, the viz should look something like this:

Step 3

Check if the connection is working and the PC is getting the steering values. After running roscore [To iniciate to ROS "service"], run: rostopic echo /cmd_vel This shows the twist messages, direction, the master (laptop) is receiving.

Controller Setup

To control the car using a video-game controller, please install the joy ROS package.

sudo apt-get install ros-noetic-joy

A more detailed description with the required drivers is available in the Guide to Software installation.

Car Batteries

Currently, Automec has the Absima GreenHorn 5000mAh 2S LiPo batteries and a Charger APC-1. This means that the batteries can hold a maximum of 8,4V and a recomended minimum of 7,4V. It should be charged on the Balance-Charge mode, and, as it is usual in LiPo batteries, it can charge at 1C, that is, in our case, 5A. The charger stops automatically as it reaches 8,4V. As it charges, it should be placed inside the fire-resistant container used for its storage. If you desire to read more into LiPo batteries, Roger's Hobby Center has a very interesting guide in here.

A few simple steps in order to correctly charge the battery:

Connect the charger to your domestic electricity using plug 8;
Connect balance adapter cable to the charger on plug 7;
Connect the battery to the first plug in the balance adapter;
Connect the battery to the charger, using plug 6. Be careful and connect according to the colours. That is, the red cable to the red plug and the black cable to the black plug;
Select the battery tipo (LIPO Battery), select the mode (BAL-CHR), number of cells (2S), battery capacity (5000mAh) and the charging current (5A). You can select these parameters using the START button to confirm, the plus (+) button to increase, the minus (-) button to decrease and the STOP button to return to the last parameter;
Press the START button during 2 seconds to start the charging process.