ivorhoulker/presence-car

Car Socket on Pico

Check [/arduino/test-2-socket] - latest version is a websocket server on the pico, which handles sending and receiving json.

Dependencies:

khoih-prog/WebSockets2_Generic@^1.13.2
khoih-prog/EthernetWebServer@^2.3.0

Car OSC Server on Pico

Check [/arduino/test-2-ethernet]. Receives and sends OSC signals over ethernet. An osc signal consists of a string address (like /command/move) and number/boolean data in an array (like [225, 100, 10]).

This is probably deprecated in favour of the websocket version, which works on android and is better suited to commands that need to be sure of arrival.

Common errors

• Remember to close the serial monitor before updating the code on the pico.
• Ensure you have the correct version of OSC bundle, it should be installed via .zip file, and it uses version 1.3.5: https://github.com/CNMAT/OSC/releases

Car Socket Server in Node

A local socket process to run on cars/robots to receive controls from a phone running the Presence app.

The code is written in typescript, and transpiled to javascript (a dist directory is created on build). The typescript definitions and constants come from a package published from a separate monorepo, @rphk/constants, which is installed like any regular npm package. To expand functionality, you will want to look at the socket listeners and emitters in app.ts.

socket.on('move', (data, callback) => {
  sendWheelCommand(port, data);
  callback();
});

When the car receives a 'move' command via the server, it sends a wheel command to the serial port (via sendWheelCommand) - data is an array of four numbers. You can see the type of data by hovering over it. The events on the socket are typed, so if you wanted to add a new event, let's say, "tilt", you would also need the @rphk/constants package server type to be updated to specify that event and the data it takes.

You could still add new commands to send over serial, and trigger them manually (e.g. on start up) to test, and decide what data they need, before asking Ivor to add them to the server/frontend and @rphk/constants, so that you can add a listener for that event to trigger the command.

For example, I want to add a tilt command. I write a sendTiltCommand function. It needs to know whether to tilt upward or downward, and what speed to tilt. So I decide I will need a number between -5 and 5 as the data. Positive tilts up, negative tilts down. The higher the number, the faster. I call my function with hardcoded parameters, just after the socket connects, to confirm it works. I tell Ivor to add this functionality to the project. He updates @rphk/constants. Then I run yarn add @rphk/constants@latest and now the socket knows about this event. I can write my

socket.on('tilt', (data, callback) => {
  sendTiltCommand(port, data);
  callback();
});

and the compiler will be happy.

Installation

Installing from scratch

To connect the pi to an iphone via usb hotspot local network, you need usbmuxd - I found out here. There is a similar package for ubuntu.

On a pi, run:

sudo apt install usbmuxd

(remember, this is only for pi os, ubuntu/debian needs a different package - check the link above) You'll have to 'trust' the computer and put your passcode in on the phone.

You'll need node and npm (node package manager). It's best to use nvm (node version manager) for easy switching between versions. Check it's installed:

nvm -v

It should show a version number. If not, install it:

curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.39.2/install.sh | bash

Our process can run with node 16, among others. Let's install that:

nvm install 16
nvm alias default 16 # make sure it's now the default on start up

This installs version 16 and sets it as the active version.

I like using yarn, and my projects usually have yarn.lock files. Here, it is assumed you will use yarn to run everything.

npm i -g yarn

PM2 Setup

pm2 is used to run the process on start up, for reliable restarts and easy log access. To set it up manually:

npm install -g pm2

Run pm2 ecosystem to generate a config file. Open it with vim or nano:

nano pm2.config.js # or whatever file it said it created, make sure you're in the right directory.

Set the contents as follows:

module.exports = {
  apps: [
    {
      name: "socket",
      cwd: "./app/socket",
      script: "yarn",
      args: "start",
    },
  ],
};

Save and exit. Then:

mkdir app
cd app
git clone https://github.com/ivorhoulker/local-socket.git socket
cd socket
yarn
yarn build-ts

pm2 kill # stop any old processes, probably not necessary
pm2 start
pm2 save
pm2 log  # to check it works - exit with ctrl+c

Common errors

Can't find the nvm command or some command isn't recognised? Restart the pi if you're sure you already installed it.

Some kind of yarn berry error? Make sure to delete any yarn files in the directories above. The presence pis have a yarn workspace active in the root! This was a bad idea. Sorry. ls -a to see hidden files. Delete .yarnrc and .yarnrc.yml.

Node incompatible error? Might need to change node version. E.g. nvm install 16 or whatever version it tells you in the error.

No yarn command? npm i -g yarn

Can't connect to the socket? Check if the board is on the right ip. The default local ip of the pi seems to be 172.20.10.2 when connected to iphone (which itself is 172.20.10.1 and acts as the DNS server.) Tested this is as consistent when unplugging/replugging. Otherwise use angry ip scanner to find it on your local network. Check the ip in react native is correct.

Updating

Ssh into the pi and pull from the git repo, build, then restart the pm2 process:

cd app/socket
git pull
yarn
yarn build-ts
pm2 restart socket

Note that git pull will not override any local changes you made to files on the pi! You may want to git stash your local changes first.

Updating many cars at once

Download angry ip scanner and save yourself from having to listen to/find the local IPs of the cars manually. Use it to scan and identify all the cars - their host names are Greek heroes (Hector, Achilles, Prometheus, Theseus and Jason so far). Once you find them, reserve their ips on your router.

Download csshX so you can ssh into multiple cars simultaneously to do the updates.

csshX pi@192.168.0.1 pi@192.168.0.2 pi@192.168.0.3 # but  use the local ips of the cars
# enter password when prompted, it should fill in all screens (type in red box at bottom)

Example I usually use:

csshX pi@10.0.1.61 pi@10.0.1.62

Once ssh'ed into all cars, follow the same procedure as above.

Testing

You might want to attach directly to the process for testing. Kill pm2 and run it directly with yarn.

pm2 kill #kill pm2 temporarily while you test
cd app/socket && git pull # get latest version
yarn # install
yarn build-ts && yarn start # run the script directly to attach to the process