Bluetooth LE scanner
List nearby Bluetooth LE devices with their signal strength every ten seconds: phones, watches, beacons and sensors.
Board
ESP32
3V3
GND
EN
23
VP
22
VN
TX
34
RX
35
21
32
GND
33
19
25
18
26
5
27
17
14
16
12
4
GND
0
13
2
D2
15
D3
D1
CMD
D0
5V
CLK
Wiring
Nothing to wire. This one runs on the bare board.
Tested on this board
Not run on this board yet. Treat the wiring and code as a first draft.
Firmware, Arduino sketch for ESP32 Dev Module
#include <BLEDevice.h>
#include <BLEScan.h>
#include <BLEAdvertisedDevice.h>
BLEScan* scan;
void setup() {
Serial.begin(115200);
BLEDevice::init("");
scan = BLEDevice::getScan();
scan->setActiveScan(true); // ask devices for their names
scan->setInterval(100);
scan->setWindow(99);
}
void loop() {
BLEScanResults* found = scan->start(5, false); // scan for five seconds
int n = found->getCount();
Serial.printf("%d devices\n", n);
for (int i = 0; i < n; i++) {
BLEAdvertisedDevice d = found->getDevice(i);
Serial.printf("%s %4d dBm %s\n", d.getAddress().toString().c_str(), d.getRSSI(),
d.haveName() ? d.getName().c_str() : "(no name)");
}
scan->clearResults();
delay(5000);
}S3
3V3
GND
3V3
TX
RST
RX
4
1
5
2
6
42
7
41
15
40
16
39
17
38
18
37
8
36
3
35
46
0
9
45
10
48
11
47
12
21
13
20
14
19
5V
GND
GND
GND
Wiring
Nothing to wire. This one runs on the bare board.
Tested on this board
Not run on this board yet. Treat the wiring and code as a first draft.
Firmware, Arduino sketch for ESP32S3 Dev Module
#include <BLEDevice.h>
#include <BLEScan.h>
#include <BLEAdvertisedDevice.h>
BLEScan* scan;
void setup() {
Serial.begin(115200);
BLEDevice::init("");
scan = BLEDevice::getScan();
scan->setActiveScan(true); // ask devices for their names
scan->setInterval(100);
scan->setWindow(99);
}
void loop() {
BLEScanResults* found = scan->start(5, false); // scan for five seconds
int n = found->getCount();
Serial.printf("%d devices\n", n);
for (int i = 0; i < n; i++) {
BLEAdvertisedDevice d = found->getDevice(i);
Serial.printf("%s %4d dBm %s\n", d.getAddress().toString().c_str(), d.getRSSI(),
d.haveName() ? d.getName().c_str() : "(no name)");
}
scan->clearResults();
delay(5000);
}C3
GND
GND
3V3
TX
3V3
RX
2
GND
3
9
GND
8
RST
GND
GND
7
0
6
1
5
10
4
GND
GND
5V
18
5V
19
GND
GND
Wiring
Nothing to wire. This one runs on the bare board.
Tested on this board
Not run on this board yet. Treat the wiring and code as a first draft.
Firmware, Arduino sketch for ESP32C3 Dev Module
#include <BLEDevice.h>
#include <BLEScan.h>
#include <BLEAdvertisedDevice.h>
BLEScan* scan;
void setup() {
Serial.begin(115200);
BLEDevice::init("");
scan = BLEDevice::getScan();
scan->setActiveScan(true); // ask devices for their names
scan->setInterval(100);
scan->setWindow(99);
}
void loop() {
BLEScanResults* found = scan->start(5, false); // scan for five seconds
int n = found->getCount();
Serial.printf("%d devices\n", n);
for (int i = 0; i < n; i++) {
BLEAdvertisedDevice d = found->getDevice(i);
Serial.printf("%s %4d dBm %s\n", d.getAddress().toString().c_str(), d.getRSSI(),
d.haveName() ? d.getName().c_str() : "(no name)");
}
scan->clearResults();
delay(5000);
}Parts
| Quantity | Part | Where to buy |
|---|---|---|
| 1× | ESP32 dev board | Buy at Amazon |
Amazon buy links may include an Associates tag, and this site may earn a commission from qualifying Amazon purchases at no extra cost to you. Adafruit links are direct.
Libraries
BLE (built in)
Load it
- In the Arduino IDE, install the esp32 board package and pick the board named above the sketch.
- Paste the sketch, choose the board's port and upload. Hold BOOT if the upload stalls at Connecting.
- Close the IDE's serial monitor, then open the bench here to watch the output.
Field notes
- Written for the 3.x Arduino core, where start() returns a pointer. On the older 2.x core, use BLEScanResults found = scan->start(5, false) and found.getCount() instead.
- The Bluetooth stack is large. If the classic ESP32 build says the sketch is too big, pick Tools, Partition Scheme, Huge APP.
- Phones and watches change their address every few minutes for privacy, so the same phone can appear more than once.
- The S3 and C3 only have Bluetooth LE. The classic ESP32 also has Classic Bluetooth, which this sketch does not scan.
Not tested yet
- Not tested on hardware yet. Compiles for every board listed with Arduino-ESP32 core 3.3.12.