little-scale

Wednesday, June 25, 2025

Tutorial: How to Vibe Code Max Externals with Claude Code

Sunday, June 22, 2025

Generating a 360 Video from Still Image and 4ch Ambisonics File

Create a video from a still image. Combine the video created in the previous step with 4 channel audio. Inject the correct 360 metadata into the video created in the previous step. Requires ffmpg and spatial-media.

Download example gradient here:

https://universityofadelaide.box.com/s/q8g5f31kw5iabtishv4sg93zag2ltgzh

Download short ambix wav file here:

https://universityofadelaide.box.com/s/qrrd87dztepn4lxi3uv7m1wyj3zvgkn6

ffmpeg -loop 1 -i [input image file] -t 8 -vf format=yuv420p -c:v libx264 [output video file 1]

ffmpeg -i [input video file 1] -i [input ambisonics audio file] -c:v copy -c:a pcm_s24le -map 0:v:0 -map 1:a:0 [output video file 2]

python spatialmedia -i -a [output video file 1] [output video file 3]

Monday, June 02, 2025

xNT Hand Implant to Webhook to Home Assistant Event Trigger

https://www.instagram.com/p/DKZQHQBi4Eq/

#include <WiFi.h>
#include <HTTPClient.h>
#include <SPI.h>
#include <MFRC522.h>

// === Wi-Fi credentials ===
const char* ssid = "SSID";
const char* password = "password";

// === Home Assistant Webhook endpoint ===
const char* webhook_url = "http://HA_IP_ADDRESS:8123/api/webhook/rfid_trigger";

// === SPI Pin Assignments for Xiao ===
#define RST_PIN 3
#define SS_PIN  7

MFRC522 mfrc522(SS_PIN, RST_PIN);

// === Setup ===
void setup() {
  Serial.begin(115200);
  while (!Serial);

  Serial.println("Connecting to Wi-Fi...");
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWi-Fi connected.");

  Serial.println("Initializing RFID...");
  SPI.begin(8, 9, 10); // SCK, MISO, MOSI
  mfrc522.PCD_Init();
  Serial.println("Ready to scan tags.");
}

// === Send UID to Home Assistant via Webhook ===
void sendWebhook(String uid) {
  if (WiFi.status() != WL_CONNECTED) return;

  HTTPClient http;
  http.begin(webhook_url);
  http.addHeader("Content-Type", "application/json");

  String payload = "{\"uid\": \"" + uid + "\"}";
  int code = http.POST(payload);
  Serial.print("Sent UID: "); Serial.print(uid);
  Serial.print(" | HTTP Response: "); Serial.println(code);
  http.end();
}

// === Main loop ===
void loop() {
  if (!mfrc522.PICC_IsNewCardPresent() || !mfrc522.PICC_ReadCardSerial()) return;

  String uid = "";
  for (byte i = 0; i < mfrc522.uid.size; i++) {
    if (mfrc522.uid.uidByte[i] < 0x10) uid += "0";
    uid += String(mfrc522.uid.uidByte[i], HEX);
  }
  uid.toUpperCase();

  Serial.println("Scanned UID: " + uid);
  sendWebhook(uid);

  delay(2000); // debounce
  mfrc522.PICC_HaltA();
}

Sunday, June 01, 2025

Teensy Basics: Distance Sensing with VL53L0X Laser Sensor

Overview

The VL53L0X is a ranging sensor that uses time-of-flight of a laser to determine the distance to the next surface correct to the mm with a maximum of 2m. The sensor uses an i2c interface with a default address of 0x29. The xshut pin allows for address control and start up / shut down during setup.

Hardware Setup

Here are the pinouts for the Teensy 4.1 and the VL53L0X:

Make the following connections between the Teensy 4.1 and the sensor:

Teensy GND to VL53L0X GND
Teensy 3v3 to VL53L0X VIN
Teensy pin 0 to VL53L0X XSHUT
VL53L0X unconnected
Teensy pin 18 to VL53L0X SDA
Teensy pin 19 to VL53L0X SCL

No other passive components are required.

Software setup

This sensor example requires the Pololu vl53l0x library, which is available from the Arduino library manager.

Example: Reading distance and printing to the serial monitor

#include <Wire.h>
#include <VL53L0X.h>

VL53L0X sensor;

// XSHUT pin for VL53L0X
const int XSHUT_PIN = 0;

void setup() {
  Serial.begin(115200);
  Wire.begin(); // SDA = 18, SCL = 19 on Teensy 4.1
  delay(100);

  // Initialize XSHUT pin
  pinMode(XSHUT_PIN, OUTPUT);
  digitalWrite(XSHUT_PIN, LOW);   // Reset sensor
  delay(10);
  digitalWrite(XSHUT_PIN, HIGH);  // Power up sensor
  delay(10);

  // Initialize VL53L0X
  sensor.setTimeout(500);
  if (!sensor.init()) {
    Serial.println("Failed to detect VL53L0X.");
    while (1);
  }

  sensor.startContinuous();
  Serial.println("VL53L0X started.");
}

void loop() {
  uint16_t distance = sensor.readRangeContinuousMillimeters();

  Serial.print("Distance: ");
  Serial.print(distance);
  Serial.println(" mm");

  if (sensor.timeoutOccurred()) {
    Serial.println("TIMEOUT");
  }

  delay(20);
}