Category Archives: IOT / Domoticz

Mac Address scanner for my home.

I bought 4x Xiao-S3 mini controllers. I want to place these all over my house to scan for Bluetooth and Wifi Clients. So I can do a location search for Mobile Phones, Keys and more.

Also the Bluetooth tags I used for the Scanner Game can be used!

I want to post a location to Home Assistant, But I also played with 3D view.

Using MQTT I can subscribe to the topic locator/scanner1/ble or locator/scanner1/wifi_clients

Problems I ran into.

Too many duplicates, fixed.
Can not scan Wifi when connected, so I connect every 30s.
Could not find all wifi clients, needed to scan all channels!

CODE

#include <WiFi.h>
#include <PubSubClient.h>
#include <BLEDevice.h>
#include <BLEScan.h>
#include <BLEAdvertisedDevice.h>
#include "esp_wifi.h"

const char* mqtt_server = "MQTTSERVER";   // change to your broker
const int   mqtt_port   = 1883;
const char* mqtt_user   = "";
const char* mqtt_pass   = "";

const char* ssid     = "MYWIFI";
const char* password = "MYWIFIPASSWD";

WiFiClient espClient;
PubSubClient client(espClient);

#define MAX_BUFFER 200

struct DeviceRecord {
  String type;   // "wifi_client" or "ble"
  String mac;
  int rssi;
};

DeviceRecord buffer[MAX_BUFFER];
int bufferCount = 0;

// ====== BLE ======
BLEScan* pBLEScan;
const int bleScanTime = 3; // seconds

typedef struct {
  unsigned frame_ctrl:16;
  unsigned duration_id:16;
  uint8_t addr1[6];
  uint8_t addr2[6];
  uint8_t addr3[6];
  uint16_t sequence_ctrl;
  uint8_t addr4[6];
} wifi_ieee80211_mac_hdr_t;

typedef struct {
  wifi_ieee80211_mac_hdr_t hdr;
  uint8_t payload[0];
} wifi_ieee80211_packet_t;

void formatMAC(const uint8_t *addr, char *buf) {
  sprintf(buf, "%02X:%02X:%02X:%02X:%02X:%02X",
          addr[0], addr[1], addr[2], addr[3], addr[4], addr[5]);
}

// ====== Dedup ======
void addToBuffer(String type, String mac, int rssi) {
  for (int i = 0; i < bufferCount; i++) {
    if (buffer[i].mac == mac && buffer[i].type == type) {
      buffer[i].rssi = rssi;  // update latest RSSI
      return;
    }
  }
  if (bufferCount < MAX_BUFFER) {
    buffer[bufferCount].type = type;
    buffer[bufferCount].mac = mac;
    buffer[bufferCount].rssi = rssi;
    bufferCount++;
  }
}

// ====== Sniffer ======
void wifi_sniffer_packet_handler(void* buf, wifi_promiscuous_pkt_type_t type) {
  if (type != WIFI_PKT_MGMT && type != WIFI_PKT_DATA) return;

  const wifi_promiscuous_pkt_t *ppkt = (wifi_promiscuous_pkt_t *)buf;
  const wifi_ieee80211_packet_t *ipkt = (wifi_ieee80211_packet_t *)ppkt->payload;
  const wifi_ieee80211_mac_hdr_t *hdr = &ipkt->hdr;

  char mac[18];
  formatMAC(hdr->addr2, mac);
  int rssi = ppkt->rx_ctrl.rssi;

  addToBuffer("wifi_client", String(mac), rssi);
}

// ====== BLE CALLBACK ======
class MyAdvertisedDeviceCallbacks: public BLEAdvertisedDeviceCallbacks {
  void onResult(BLEAdvertisedDevice advertisedDevice) {
    String mac  = advertisedDevice.getAddress().toString().c_str();
    int rssi    = advertisedDevice.getRSSI();
    addToBuffer("ble", mac, rssi);
  }
};

void startSniffer() {
  WiFi.mode(WIFI_STA);        // keep STA mode
  WiFi.disconnect();          // ensure not connected

  wifi_promiscuous_filter_t filter = {
    .filter_mask = WIFI_PROMIS_FILTER_MASK_MGMT | WIFI_PROMIS_FILTER_MASK_DATA
  };
  esp_wifi_set_promiscuous_filter(&filter);
  esp_wifi_set_promiscuous_rx_cb(&wifi_sniffer_packet_handler);
  esp_wifi_set_promiscuous(true);

  esp_wifi_set_channel(1, WIFI_SECOND_CHAN_NONE);
  Serial.println("Sniffer ON (starting on channel 1)");
}

void stopSniffer() {
  esp_wifi_set_promiscuous(false);
  Serial.println("Sniffer OFF");
}

void publishBuffer() {
  Serial.println("Connecting to WiFi for MQTT...");
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  unsigned long startAttempt = millis();
  while (WiFi.status() != WL_CONNECTED && millis() - startAttempt < 10000) {
    delay(200);
    Serial.print(".");
  }
  Serial.println(WiFi.isConnected() ? "\nWiFi connected" : "\nWiFi connect failed");

  if (WiFi.isConnected()) {
    client.setServer(mqtt_server, mqtt_port);
    if (client.connect("ESP32Scanner4", mqtt_user, mqtt_pass)) {
      Serial.println("MQTT connected");
      for (int i = 0; i < bufferCount; i++) {
        String payload = "{";
        payload += "\"type\":\"" + buffer[i].type + "\",";
        payload += "\"mac\":\"" + buffer[i].mac + "\",";
        payload += "\"rssi\":" + String(buffer[i].rssi);
        payload += "}";
        if (buffer[i].type == "ble")
          client.publish("locator/scanner4/ble", payload.c_str());
        else
          client.publish("locator/scanner4/wifi_clients", payload.c_str());
        delay(5);
      }
    } else {
      Serial.println("MQTT connect failed");
    }
  }
  client.disconnect();
  WiFi.disconnect(true, true);
  bufferCount = 0; // clear buffer
  Serial.println("Published & WiFi disconnected");
}

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

  // BLE init
  BLEDevice::init("");
  pBLEScan = BLEDevice::getScan();
  pBLEScan->setActiveScan(true);
  pBLEScan->setAdvertisedDeviceCallbacks(new MyAdvertisedDeviceCallbacks());

  startSniffer();
}

unsigned long lastPublish = 0;
const unsigned long publishInterval = 30000; // 30s
unsigned long lastChannelHop = 0;
uint8_t currentChannel = 1;

void loop() {
  // BLE scan while sniffing
  pBLEScan->start(bleScanTime, false);
  pBLEScan->clearResults();

  // Channel hopping !
  if (millis() - lastChannelHop > 500) {
    lastChannelHop = millis();
    currentChannel++;
    if (currentChannel > 13) currentChannel = 1;
    esp_wifi_set_channel(currentChannel, WIFI_SECOND_CHAN_NONE);
    // Serial.printf("Hopped to channel %d\n", currentChannel);
  }

  // Every 30s
  if (millis() - lastPublish > publishInterval) {
    lastPublish = millis();
    stopSniffer();
    publishBuffer();
    startSniffer();
  }
}

LED String with 1D game

I saw a game like this on the WHY2025, I wanted my own version.

Using Twang32, some other hardware and a tweaked sketch, I got this.

Up = move up
Down = move down
whack the stick to kill red leds (Metal part is a door spring)
(Tilting joystick also works as up/down)

Things changed:

  • Other hardware: MPU6050 for movement detection, Sound generation
    No clock on my LedString
  • Changed sketch, fastled, pins and libraries
  • Using IDE in 2025? .. downgrade ESP32 (expressive) to 2.0.11, and download Fastled to 3.9.0
    2025 libraries won’t work!

Antenna tweaking

A while ago I was playing with LoRa (Long Range radio), I made a simple setup which worked good enough.

After that I installed Meshtastic

I also used OpenMqttGateway with LoRa.

I’ve been using antennas also with SDR(Software Defined Radio.

Not happy with the performance, I bought a Nano-VNA.
(Vector network analyser)

Due to the many options, I was lost at first. Maybe I have to ask Bigred.
Calibrating I get now, but I can’t easily calibrate an antenna with fixed cable.

Much to learn, but that’s what I want. 🙂

I bought a VNA/Antenna test board from Ali.

Feature:

  1. RF Demo Kit RF test board demo calibration board for learning Vector Analyzer and Antenna Analyzer test calibration.
  2. The board is fully integrated with 18 functional modules.
  3. Equipped with 2 UFL patch cords for convenient use.
  4. Each module is carefully selected for high quality and reliability.
  5. The board is small and lightweight, easy to carry.

Specification:

Product type: RF Demo Kit

  1. Filters:
    • A. Short low-pass filter (LPF): 30 MHz
    • B. FM high-pass filter (HPF): 100 MHz
    • C. Commonly used SAW band-pass filter (BPF): 433 MHz
    • D. Video ceramic notch (band-stop filter, BSF): 6.5 MHz
  2. RLC series and parallel circuits
    • Includes R, L, C and combination circuits
  3. Open/short and load calibration circuit
  4. Attenuation circuit

Package List:

  • 1 × RF Demo Kit Board
  • 2 × UFL patch cables

WHY2025

In case of doubt .. MORE LEDS!

We went to WHY2025 a hackers camp in the Netherlands.

The first time I went was in 1997, with Bigred.
Many followed after that.
Tyrone, Bigred were also there from our old Crew.
Coline joined me several times since 2005.

I joined the Badge team, and was making spacers for the Badges in bulk using my 3D printer.
Also made some fancy cases.

In case of doubt .. more leds!

Nice weather, good friends. New friends. Booze. Food and Hacking.
We visited a lot of talks and enjoyed the music. (And fire)

I worked on: RSS feed on a epaper display, Midi monitor and the MQTT Pong website.

RSS Feed display

While waiting in line for the Badge:

A stone was passed from behind!
It was a ping request. We passed it forward, and 15 minutes later a TTL time exceeded stone came from the front of the line.
You gotta love those nerds!

The Badge:
This should have got much potential ..
Many misses, much to learn.

Sadly broken:

Our 7M Led string attached to Bigred’s Antenna.

BirdNet installation

I bought Peterson’s Vogelgids, just for fun.
It’s an old version, but that’s on purpose.

Then I saw a little project named BirdNet Pi.
(I used the Android app already)

This is a Raspberry installation which recognises bird sounds. And gives you statistics about the detected birds.
Cool for identifying birds in my garden.

Next to do : Integration in Home Assistant

Bert Visscher has the same book.

Cynthcart (c64) midi control

I bought a teensyrom a while ago.

UPDATE 20250712 : Display

Tyrone and I wanted to control the settings using potmeters.
So I grabbed a Teensy 4.1 controller and some 10K potmeters, and worte some code

Code for 12 pots, pitch bend and display, don’t forget to set your USB mode to midi!
Schematic soon, also all tweaks and note sending.

Todo: Nice 3D printed Pitch Bend wheel, rest of display code and extra buttons!

Let’s use an old box to hold the pots!

3D printed wooden knobs (Yes wood filament)
Unstable release pot due too bad wires. Cynthcart has no decay and hold (hold is how long you are pressing key)


#include <MIDIUSB.h>
#include <Adafruit_GFX.h>
#include <Adafruit_SSD1306.h>

#define SCREEN_WIDTH 128 // OLED display width, in pixels
#define SCREEN_HEIGHT 64 // OLED display height, in pixels
#define OLED_RESET 4
Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);

// A0 -> A3, A6 -> A13
const int numPots = 12;

// A14 - Pitch bend!
int lastPitch = -1;

//A4 A5 I2C display


// Custom mappings:
const int potPins[numPots]     = {A0, A1, A2, A3, A6, A7, A8, A9, A10, A11, A12, A13};  // Analog pins
const int ccNumbers[numPots]   = {0,1,2,3,4,5,19,7,8,9,13,14};             // CC numbers
const int midiChannels[numPots]= {1,1,1,1,1,1,1,1,1,1,1,1};                // MIDI channels (1–16)

int lastValues[numPots];  // Store last values to reduce redundant MIDI messages

void setup() {
  for (int i = 0; i < numPots; i++) {
    pinMode(potPins[i], INPUT);
    lastValues[i] = -1;
  }
  display.begin(SSD1306_SWITCHCAPVCC, 0x3C);
  display.setTextSize(2);
  display.setTextColor(WHITE);
  display.clearDisplay();
  display.display();
}

void loop() {
  for (int i = 0; i < numPots; i++) {
    int analogValue = analogRead(potPins[i]);
    int midiValue = analogValue / 8;  // Scale 0–1023 to 0–127

    if (abs(midiValue - lastValues[i]) > 1) {
      usbMIDI.sendControlChange(ccNumbers[i], midiValue, midiChannels[i]);
      lastValues[i] = midiValue;
    }
  }
  int potValue = analogRead(A12);         // Read pot (0–1023)
  int pitchBend = map(potValue, 0, 1023, 0, 16383); // Map to MIDI Pitch Bend range

  if (abs(pitchBend - lastPitch) > 5) { // Send only on significant change
    sendPitchBend(pitchBend, 0); // Channel 1
    lastPitch = pitchBend;
  }

  displayInfo();


  delay(5);  // CPU-friendly update rate
}

void sendPitchBend(int value, byte channel) {
  byte lsb = value & 0x7F;
  byte msb = (value >> 7) & 0x7F;

  midiEventPacket_t pitchBendPacket = {0x0E, 0xE0 | (channel & 0x0F), lsb, msb};
  MidiUSB.sendMIDI(pitchBendPacket);
  // Needed? 
  MidiUSB.flush();
}

void displayInfo(){
 byte x0, y0, x1, y1;     // start/end coordinates for drawing lines on OLED
  display.clearDisplay();
  display.setCursor(0, 0);
  display.print("Attack / Release");

  // draw attack line
  x0 = 0;
  y0 = 63;
  x1 = map(attackParam, 0, 127, 0, ((SCREEN_WIDTH / 4) - 1));
  y1 = 20;
  display.drawLine(x0, y0,  x1,  y1, SH110X_WHITE);

   // draw release line
  x0 = x1;  // start line from previous line's final x,y location
  y0 = y1;
  x1 = x0 + map(releaseParam, 0, 127, 0, ((SCREEN_WIDTH / 4) - 1));
  y1 = 63;
  display.drawLine(x0, y0,  x1,  y1, SH110X_WHITE);

  display.display();

}

Working on a Bluetooth beacon game for a friend.

Got some bluetooth beacons in the mail.

The plan is to hide these in the woods, and children have to find them using a scanner device.

3D printed scanner (model not mine, but changed to hold electronics

Using a ESP32 with bluetooth, using RSSI (strength of signal) I can limit the range of detection.

The order of finding the tags is important, so a hidden tag should not be found when another should be found first.

These tags, hidden in toys, should be placed in a treasure chest.
(In order)
Then lights and sounds should hint the kids that they have successfully completed the mission.

New version has a beeper on the left. .. sorry .. hayfever

So same detecting but even shorter range ESP is hidden in the Chest.

Some leds or a single blinking one should give hints about the distance of the object.

=== Matching iTags ===
MAC: 5b:08:10:4d:2a:01 | RSSI: -47
MAC: 5b:45:aa:0d:f7:9c | RSSI: -31 #### NEAR 
MAC: 5b:88:fc:fc:e8:a9 | RSSI: -94 #### FAR AWAY
MAC: 5b:8b:00:00:1d:40 | RSSI: -66 

Some test code:

#include <BLEDevice.h>
#include <BLEUtils.h>
#include <BLEScan.h>
#include <BLEAdvertisedDevice.h>

int scanTime = 5; // seconds
BLEScan* pBLEScan;

void setup() {
  Serial.begin(115200);
  Serial.println("Starting BLE scan...");

  BLEDevice::init("");
  pBLEScan = BLEDevice::getScan();
  pBLEScan->setActiveScan(true);
  pBLEScan->setInterval(100);
  pBLEScan->setWindow(99);
}

void loop() {
  BLEScanResults results = *pBLEScan->start(scanTime, false);
  Serial.println("=== Matching iTags ===");

  for (int i = 0; i < results.getCount(); i++) {
    BLEAdvertisedDevice device = results.getDevice(i);
    String mac = device.getAddress().toString();

    if (mac.startsWith("5b:")) {
      Serial.print("MAC: ");
      Serial.print(mac);
      Serial.print(" | RSSI: ");
      Serial.println(device.getRSSI());
    }
  }

  Serial.println("======================");
  pBLEScan->clearResults();
  delay(2000);
}

Weather display using LilyGO T5-4.7 inch S3 E-paper E-ink ESP32-S3

I was planning to make a RSS reader using this display, but I came across a weather display project I wanted to check out.
(So I probably end up buying another one)

There are many questions and issues around this project using the S3.

So here is my solution.

Install vscode

Goto plugins and install platformio

git clone https://github.com/Xinyuan-LilyGO/LilyGo-EPD-4-7-OWM-Weather-Display.git

Warning this is NOT the branch you want to use

git checkout web

(git pull)

open directory in code

open platformio.ini and change line 13
default_envs = T5_4_7Inc_Plus_V2
(If needed add upload_port = /dev/tty**** at the end)

Change INO file lines 144-146.
Comment serial out, else update won’t work using regular power or battery.



When saving this platformio.ini file, some downloading and installing should be popping up.
When issues occur about libraries see below.

Fill out
data>config.json
and owm_credentials.h to be sure.
(use owm_credentials information to fill config.json)

Next press the platformio icon

Fix for uploading:

Press and hold STR_IO0 button
Press REST button
Release STR_IO0 button

Libraries:

Press platformio icon, libaries and install ArduinoJson, Button2 and LilyGo-EPD47 (select your project while doing so!)

Note: Per default once per hour update, change if you want to.
Line 70 in the INO file

Build/Upload errors? .. Press clean to recompile using a clean state !