Week 12 -- Networking!

In contrast to the insane projects the Serious People pull off in HTM, I proudly present: Hello World.

It'd be easy, right? right?

Group assignment

Making Kyle's whoop-whoop instrument let the mouse wave. I provided lots of rookie questions, and... USB-C power.

A Michelle caught in the wild.

Solo adventures

AI folks are excited by a GPT or Llama launch, but for us neuro folks, the fly connectome dropped! I recently ended up working both on making that fly live digitally, and spinning up a team for a vaccine against sleep. Holy smokes, I was grateful for a light week like networking.

Easy, right?

I took two Xiao Seeed ESP32 S3. One on my final project MVP board, one breadboarded to... blink.

Here's what I first tried to set up a WiFi server:

#include <WiFi.h>

const char* ssid = "ESP32_Server";
const char* password = "12345678";
const int serverPort = 8080;

WiFiServer server(serverPort);

void setup() {
  Serial.begin(115200);
  WiFi.softAP(ssid, password);
  server.begin();
}

void loop() {
  WiFiClient client = server.available();
  if (client) {
    while (client.connected()) {
      if (client.available()) {
        String request = client.readStringUntil('\r');
        client.println("Hello World");
        client.stop();
      }
    }
  }
}

So, the server setup worked okay. It was awesome seeing it pop up on my feed.

I iterated on this, and set up a client side too. The next iteration of the client-side would blink in response to finding the server (→ output).

Based on an online tutorial, here's one of the later versions of the WiFi server I tried to set up:

#include <WiFi.h>
#include <esp_now.h>

uint8_t receiverMAC[] = {0x24, 0x6F, 0x28, 0xXX, 0xXX, 0xXX};

struct Message {
  bool blink;
} message;

void setup() {
  Serial.begin(115200);
  WiFi.mode(WIFI_STA);
  if (esp_now_init() != ESP_OK) return;

  esp_now_peer_info_t peerInfo;
  memcpy(peerInfo.peer_addr, receiverMAC, 6);
  peerInfo.channel = 0;
  peerInfo.encrypt = false;

  if (esp_now_add_peer(&peerInfo) != ESP_OK) return;

  Serial.println("Ready to send");
}

void loop() {
  message.blink = true;
  if (esp_now_send(receiverMAC, (uint8_t *)&message, sizeof(message)) == ESP_OK) {
    Serial.println("Message sent");
  } else {
    Serial.println("Send error");
  }
  delay(2000);
}

The hardest intermediate challenge I faced was actually making the Arduino serial monitor MONITOR stuff.

[Find and add late-stage code]

Somewhere between lots of waiting, having the server ESP running and flashing the client one, I finally got a blink:

But I'm not fully sure that it blinked correctly or whether I rebooted some blinker code. Next steps would be probably to fix the serial monitor issue, and redo the same for e.g. bluetooth.

[To be continued for the final project...]