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Ships

Wondering what a ship is? Watch this video! Basically, a ship is when you make your project experiancable by others. In this case, that is writing a README about the project and adding some videos so people can see what it is!

Version 3

Features:

• Overall:
  • Low latency human driving using cellular
  • Waypoint driving using RTK GPS (under 30mm accuracy)
• Vehicle:
  • Hoverboard motors (very high tourque)
  • Neopixels for headlights and direction lights (red and green)
  • Camera for driving
  • GoPro monuts for videos (not needed to drive, only for extra video)
  • Handles because it weighs 35lbs (around 15kg)
  • Tech specs:
    • Nvidia Jetson Orin Nano
    • SIM7600 cell modem
    • SparkFun GPS-RTK2 Board
    • Hoverboard ECS's
    • 16Ah 4S LiPo battery
• Website:
  • Live video from tank (under 100ms control loop)
  • Live telemetry from tank:
    • Location
    • RTK GPS status
    • Battery voltage
    • Ping
    • Heading
  • Map:
    • View live location of tank
    • Create waypoint routes
    • Send routes to tank
    • Download and upload routes as JSON files
  • Tank settings:
    • Car mode (off lets you control each wheel by itself)
    • Lights
    • FrSky mode (for nicer controlers)
    • Self driving toggle
    • Video toggle
    • Refresh rate setting
  • Go check out the website at rc.nicosmith.net! (Enter anything into text box and click connect)

Version 3 of this project has been based around adding waypoint following capabilities to the tank. There should also be version 3.5 coming out soon which will add ML features, such as staying on sidewalk and avoiding humans. This version has taken a while, but it is well worth it. The project as a whole has taken over 110 hours over 112 days (see, it really is a little bit every day). I redid the entire website UI, redid entire tank-side python software, and added waypoint following code. I have learned a lot about everything, from how much of a pain CSS can be, to how WebRTC doesn't follow system routing priorities, to how people are jerks and will steal stuff. Here are some awesome pictures and videos!

Go look at the build journal (its pretty long): here!

Videos!

Versions 1 & 2

This is version 2 of my RC-Tank. It is no longer a tank but whatever. I created both versions 1 and 2 for Hack Club Moonshot.

The idea of this project was simple, I had a normal rc car with camera, but it coulden't even go around the block, so I wanted something that would have much better range. Thats where using a cell modem comes in. The main (and big) disadvantage with this is latency, you need < 1.5s or else it becomes very hard to drive. I learned a lot doing this project (not done though!), I spent a lot of time learning about motor contollers and reverse engineering some hoverboard ECS's so I could use the motors I had. The main thing I want to keep working on, is the latency over cell, hopefully I can get webRTC working also. After I have a working human controled rover, then I will use it as the testbed for many more projects such as AI vision control, and GPS waypoints.

Setup

Internet

Install Tailscale

Go to login.tailscale.com/admin/machines and follow instructions for new linux device.

Use this command to start it so ssh will work: sudo tailscale up --reset --netfilter-mode=off --ssh.

Turn off wifi power saving

sudo iw dev wlP1p1s0 set power_save off

You might need to use something like ifconfig -a to find the right network interface.

Add networks and set wifi priority

sudo nmtui

sudo nmcli c mod "mypreferred" conn.autoconnect-priority 10

to set priority; higher number is higher priority.

Cmd to temp use wifi

sudo ip route del default via 192.168.1.1 dev wlan0
sudo ip route add default via 192.168.1.1 dev wlan0 metric 50

Cmd to dissconnect from WiFi

sudo ip link set wlan0 down

sudo ip link set wlan0 up

Jetson specific

Configure GPIO for SPI

To use SPI on the GPIO pins, you must first run the Jetson-IO python script and enable SPI1 (no idea why you need SPI1 for SPI0).

sudo /opt/nvidia/jetson-io/jetson-io.py

Resize file system after copying from SD to SSD

sudo apt install cloud-utils
sudo growpart /dev/nvme0n1 1
sudo resize2fs /dev/nvme0n1p1

Wiring

(Wire color is to just help me)

Pin #	Purpose	Item	Wire Color
2	5V	Compass Power	Red
3	I2C1_SDA	Compass Data	Orange
5	I2C1_SCL	Compass Data	Brown
6	GND	ESC Serial Ground	Green
8	UART1_TX	ESC UART RX	Purple
9	GND	Compass Ground	Black
10	UART1_RX	ESC UART_TX	Yellow
19	SPI_0	Lights Control	Orange

Website

You first need to directly go to one of the API endpoints to accept the self signed cert. Remember that you have to use the :5000 port!

Custom TURN / STUN server

sudo apt install coturn

sudo ufw allow 3478/udp sudo ufw allow 3478/tcp sudo ufw allow 50000:50050/udp

Edit /etc/turnserver.conf

listening-port=3478
listening-ip=<YOUR_PUBLIC_IP>
external-ip=<YOUR_PUBLIC_IP>
realm=rc-tank
user=tank:tankpass
lt-cred-mech
fingerprint

min-port=50000
max-port=50050

sudo systemctl restart coturn sudo systemctl enable coturn

Set the correct IP inside of webrtc.py and webrtc.ts

Running the tank

sudo JETSON_MODEL_NAME=JETSON_ORIN_NANO python3 ./main.py