Nano ESP32 BLE Scanner
This instructables show how to use ESP32 to make wireless BLE signal scanner, all scanned data will send to the HTTP server via WiFi.
Why BLE Scanner?
BLE (Bluetooth Low Energy) signal is very common for current digital device, mobile phone, wrist band, iBeacon, assets tag. This signal not only help you pair up the devices, it also can report the device status, such as battery level, heart rate, motion (walking, running, falling), temperature, panic button, anti-loss ... etc.
It is a valuable big data for location tracking if we can collect the BLE signal at certain number of position.
In long run, the BLE scanner should fix in selected position. However, selecting a right place require trial and error. A tiny wireless BLE scanner is handy to help you check where is the right place.
Preparation
ESP32 board
I am using ESP-WROOM-32 board this time.
A Tiny Container
Any small container should be ok, I have some tiny TicTac box in hand and it just fit an ESP32 board in it, what a coincidence!
Lipo Battery
ESP32 peak current is around 250 mA. For not drawing over 1C current at anytime, Lipo Battery should over 250 mAh capacity. 852025 is the maximum size that can fit into the Tictac box and it claim it have 300 mAh, it's good enough.
Power Regulator Circuit
A 3.3 V LDO regulator, some capacitors, I have some HT7333A regulator, 22 uf and 100 uf capacitor in hand
Others
A 10k Ohm SMD resistor for pull up EN pin, a small piece of multi purpose PCB, a power switch, some coated wires, 7 pins header
ESP32 Dev Dock
In program process, it also require a ESP32 Development Dock, you may find how to make it in my previous instructables:
Trim the PCB
Measure the dimension of your tiny container and trim the PCB to fit into it.
Soldering Pin Header
Let's start soldering work from the 7 pins header and PCB.
Soldering Power Circuit
Here is the connection summary:
LDO Vin -> Vcc pin header(1) -> power switch -> Lipo V+, Charge pin header(7)LDO GND -> GND pin header(2), capacitors V- pins, ESP32 GNDLDO Vout -> capacitors V+ pins, ESP32 Vcc
Soldering Pull Up Resistor
It is the most difficult soldering work in this project, the pin width in ESP32 board is only 1.27 mm. Fortunately, Vcc and EN pin is nearby, it can direct soldering resistor between both pin without wire.
ESP32 Vcc pin -> 10k Ohm resistor -> ESP32 EN pin
Soldering Program Pins
Here are the connection summary:
Tx pin header(3) -> ESP32 Tx pinRx pin header(4) -> ESP32 Rx pinProgram pin header(5) -> ESP32 GPIO 0 pinRST pin header(6) -> ESP32 EN pin
Cleaning Up the TicTac Box
- Eat all sweets
- Remove the stickers
Squeeze Into the Box
Squeeze all component into the TicTac box, be careful don't tear off any wires.
Prepare Software
Arduino IDE
Download and install Arduino IDE if not yet:
https://www.arduino.cc/en/Main/Software
arduino-esp32
Install hardware support for ESP32
Detailed instructions for installation in popular operating systems.
For Linux: https://www.arduino.cc/en/Guide/Linux (see also the Arduino playground page https://www.arduino.cc/en/Guide/Linux
For macOS X: https://www.arduino.cc/en/Guide/Linux
For Windows: https://www.arduino.cc/en/Guide/Linux
Program the ESP32
- Download the Arduino program: https://github.com/moononournation/Arduino_BLE_Sca...
- Modify parameters:
#define WIFI_SSID "YOURAPSSID"#define WIFI_PASSWORD "YOURAPPASSWORD"#define POST_URL "http://YOURSERVERNAMEORIP:3000/"
- Select Board: Any ESP32 board
- Select Partition: No OTA / Minimal SPIFFS
- Upload
Receive Data
If you are not yet have any HTTP server to receive the POST data, you may try to use this simple Node.js program: https://github.com/moononournation/post_data_rece...
Here are the sample data received:
Tue Mar 20 2018 08:44:41 GMT+0000 (UTC): [{ "Address": "6e:3d:f0:a0:00:36", "Rssi": -65, "ManufacturerData": "4c0010050b1047f0b3" }, { "Address": "f8:04:2e:bc:51:97", "Rssi": -94, "ManufacturerData": "75004204018020f8042ebc5197fa042ebc519601000000000000" }, { "Address": "0c:07:4a:fa:60:dd", "Rssi": -96, "ManufacturerData": "4c0009060304c0a80105" }]
Power Measurement
The program scan BLE signal for 30 seconds, then deep sleep 300 seconds and then scan again. For each loop, it consume around 3.9 mWh.
Theoretically, it can run: (I will update the testing result later on my Twitter)
300 mAh Lipo / 3.9 mWh @ 330 seconds= [(300 mA * 3.3 V) mWh / 3.9 mWh * 330] seconds~83769 seconds~23 hours
2018-04-08 Update:
I have changed to use XC6503D331 LDO regulator and made 2 measurements:
Round 1: 12:43:28 - 16:42:10 (~20 hours) 210 BLE scan POST received
Round 2: 10:04:01 - 05:36:47 (~19.5 hours) 208 BLE scan POST received
Happy Scanning!
It time to find a place to setup you BLE tracking network!