Single Board BLE to WiFi Bridge
by Matthew Ford 14th Jan 2023 (originally posted 4th
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Jan 2023 – installing ESP32 V2.0.6
board support seems to fix the previous problems with Adafruit
QT Py ESP32-C3)
Update: 28th June 2022 – Do not purchase the Adafruit QT Py ESP32-C3 with a USB-C as it is broken, see below.
project demonstrates using a single single ESP32-C3
board as a BLE scanner, a web page server refreshing a web page every
5secs, a Telnet server and NTP UDP time client, all
running at the same time.
Update 14th Jan 2023: Installing ESP32 V2.0.6 seems to fix the problems with Adafruit QT Py ESP32-C3
QT Py ESP32-C3 with a USB-C connector should also work, but on
testing was found to be broken. Using ESP32 board support V3.0.2, the
example Sketches LITTLEFS_test.ino and SPIFFS_Test.ino both fail to
run. These example run fine on the ESP32-C3
which is the same price, so purchase that one instead.
Other reasons not to use the Adafruit QT Py ESP32-C3, the USB driver does now work on Windows 7, the ESP32C3 works fine. It is tricky to reconnect the Serial Monitor to the Adafruit QT Py ESP32-C3 after programming. Also see the Adafruit forum issue.
The ESP32 Sparkfun Thing was also tested but did work successful as a single board BLE to WiFi bridge
A number of other projects use a two board BLE to WiFi bridge, Simple WiFi to Bluetooth Low Energy (BLE) Bridge, BLE Room Temperature controlled Heater with Timer Switch and BLE Low Power Indoor/Outdoor Weather Station. Those projects use an Adafruit Feather nRF52 Bluefruit LE and a Adafruit HUZZAH ESP8266 Breakout for a total cost of ~US$35 for the boards plus a USB to TTL programming cable for the HUZZAH ESP8366 (~US$10). This project looks are replacing those boards with a single ESP32C3 (~US$10, no special programming cable needed). In the case of the BLE Room Temperature controlled Heater with Timer Switch, as single ESP32C3 with NTP can replace the Power Timer ( ESP-01 and a relay module) as well as replacing the Adafruit Feather nRF52 and Adafruit HUZZAH ESP8266.
The ESP32 documents RF Coexistence between BLE and WiFi (local copy 1/06/2022 here). Although that documentation is for ESP32's in general, this project only uses the ESP32 C3 coded via the Arduino IDE V1.18.19 with the ESP32 V2.0.3 board support installed. Other setups while their own set of bug/features. The ESP32 C3 only has on core. The RF Coexistence mentions a number of ESP32 menuconfig options none of which are configurable via the Arduino IDE. The existing settings in ESP32 board support V2.0.3 were used.
Mini Development Board (with embedded flash) –
~US$9 Note: this
is NOT the slightly more expensive ESP32-C3 WROOM board
5V USB supply and cable – ~US$3 to ~US$8 from various sources, e.g. Wall Adapter Power Supply - 5.1V DC 2.5A from Sparkfun. The one used in this project is 5V DC 1A Ultra-Slim Power Supply – MP3144 from Jaycar
Small Plastic box – ~US$2.50 e.g. Jaycar HB6004.
Arduino IDE and the ESP32 V2.0.3 board support via the IDE board manager. This project used ESP32 V2.0.3. Other versions will their own set of features/bugs.
This source code also needs the following libraries:-
SafeString V4.1.21+ installed via the Arduino IDE Library Manager and
Download the ESPAutoWiFiConfig.zip, library zip file and install it using the Sketch → Include Library → Add .ZIP File menu in the Arduino IDE .
Total cost, as at June 2021, excluding shipping – ~US$15.5 to ~US$20.5.
Install Arduino V1.8.19 and then follow these instructions to install the ESP32 board support. Adafruit has instructions on installing usb-com drivers if you need to.
Open the Arduino IDE and select the ESP32 C3 board and the Huge (3MB) Partition scheme.
The following libraries are also needed. SafeString V4.1.21+ installed via the Arduino IDE Library Manager and download the ESPAutoWiFiConfig.zip, library zip file and install it using the Sketch → Include Library → Add .ZIP File menu in the Arduino IDE .
Unzip ESP32C3_BLE_Scanner_ServerTCP_UDP_NTP.zip to your Arduino Sketch directory and open the ESP32C3_BLE_Scanner_ServerTCP_UDP_NTP.ino sketch and program the ESP32C3 board. This sketch has DEBUG #defined and will print lots of debug info.
The ESPAutoWiFiConfig will start flashing the onboard RGB led after a few seconds and setup a private access point WiFiConfig with the password 12345678 Connect to that access point and open http://192.168.1.1 to configure your network's SSID and password and to choose a static IP for the web server and telnet server. See ESPAutoWiFiConfig page for details. Note: after reprogramming the ESP32C3 the board often restarts in WiFiConfig mode (led flashing). Just press the reset push button to use the configured WiFi settings (led blinks and goes out, i.e. WiFi connected)
Here is some sample debug output
12:14:11.743 -> ESP-ROM:esp32c3-api1-20210207 12:14:11.782 -> Build:Feb 7 2021 12:14:11.782 -> rst:0x1 (POWERON),boot:0xc (SPI_FAST_FLASH_BOOT) 12:14:11.782 -> SPIWP:0xee 12:14:11.782 -> mode:DIO, clock div:1 12:14:11.782 -> load:0x3fcd6100,len:0x438 12:14:11.782 -> load:0x403ce000,len:0x90c 12:14:11.782 -> load:0x403d0000,len:0x2358 12:14:11.782 -> SHA-256 comparison failed: 12:14:11.782 -> Calculated: a9753a4fc647c6545c1b919ef08db429130a48592727edca270f1e5a3da0d0a9 12:14:11.782 -> Expected: 3bf6ef2cf3b9eefcd4b3c70cc5d1ce5138292d101a5cb1d5db6fbebf081b0a19 12:14:11.782 -> Attempting to boot anyway... 12:14:11.829 -> entry 0x403ce000 12:14:11.999 -> 12:14:11.999 -> Using ESP32_WS2812Flasher 12:14:11.999 -> Create double reboot flag 12:14:11.999 -> loaded config 12:14:11.999 -> ssid:FCC-Wfi 12:14:11.999 -> password:z3uxhcrhs 12:14:11.999 -> staticIP:10.1.1.70 12:14:12.143 -> Connecting to WiFi 12:14:13.127 -> . 12:14:13.981 -> 12:14:13.981 -> Connected to FCC-Wfi 12:14:13.981 -> IP address: 10.1.1.70 12:14:13.981 -> connected to 12:14:14.023 -> ssid:FCC-Wfi 12:14:14.023 -> password:z3uxhcrhs 12:14:14.023 -> staticIP:10.1.1.70 12:14:14.023 -> initializeNtpSupport 12:14:14.023 -> Loaded config 12:14:14.023 -> utcTime:6 12:14:14.023 -> tzStr:AEST-10AEDT-11,M10.1.0/2,M4.1.0/3 12:14:14.023 -> TZ description 12:14:14.023 -> GMT+10 12:14:14.023 -> Daylight Saving GMT+11 starts in the 12:14:14.023 -> 1st week of Oct on Sun at 02:00 12:14:14.023 -> Daylight Saving ends in the 12:14:14.023 -> 1st week of Apr on Sun at 03:00 12:14:14.057 -> setTZfromPOSIXstr:AEST-10AEDT-11,M10.1.0/2,M4.1.0/3 12:14:14.057 -> setTZfromPOSIXstr:AEST-10AEDT-11,M10.1.0/2,M4.1.0/3 12:14:14.057 -> /timeZoneCfg.bin config saved. 12:14:14.057 -> utcTime:6 12:14:14.057 -> tzStr:AEST-10AEDT-11,M10.1.0/2,M4.1.0/3 12:14:14.057 -> webserver started 12:14:14.057 -> Ready! Use 'telnet 10.1.1.70 23' to connect 12:14:14.159 -> Sent NTP UDP request 12:14:14.668 -> responseCounter:1 12:14:14.668 -> Unix time = 1654136056 12:14:14.668 -> ShowTimeDebug 12:14:14.668 -> 12:14:14.668 -> localtime: isdst=0 yday=152 wday=4 year=122 mon=5 mday=2 hour=12 min=14 sec=16 12:14:14.668 -> gmtime: isdst=0 yday=152 wday=4 year=122 mon=5 mday=2 hour=2 min=14 sec=16 12:14:14.715 -> time: 1654136056 12:14:14.715 -> timezone: AEST-10AEDT-11,M10.1.0/2,M4.1.0/3 12:14:14.715 -> GMT+10 12:14:14.715 -> Daylight Saving GMT+11 starts in the 12:14:14.715 -> 1st week of Oct on Sun at 02:00 12:14:14.715 -> Daylight Saving ends in the 12:14:14.715 -> 1st week of Apr on Sun at 03:00 12:14:14.715 -> ctime: Thu Jun 2 12:14:16 2022 12:14:14.715 -> 12:14:16.103 -> Device name: Office Temp/RH 12:14:16.103 -> Adding Device name: Office Temp/RH 12:14:16.153 -> Device name: Garage Light 12:14:16.153 -> Adding Device name: Garage Light 12:14:16.301 -> Devices found: 2 12:14:18.132 -> Device name: Office Temp/RH 12:14:18.302 -> Devices found: 1
Here is sample web page served by the web server
You can also open a Telnet connection to port 23 and text typed into the Arduino IDE Serial Monitor will arrive at the telnet terminal and vice versa.
The ESP32 RF
Coexistence docs say
“ESP32 has only one 2.4 GHz ISM band RF module, which is shared by Bluetooth (BT & BLE) and Wi-Fi, so Bluetooth can’t receive or transmit data while Wi-Fi is receiving or transmitting data and vice versa. Under such circumstances, ESP32 uses the time-division multiplexing method to receive and transmit packets.”
and that it is better to run the BLE and WiFi on separate cores.
The ESP32 C3 only has one core so the BLE Scanner is run in a separate thread running with the same priority as the loop() thread so neither has priority over the other. The WiFi is connected first via ESPAutoWiFiConfig and then the WiFi services set up in setUpWiFiServices(). Then the BLE scanner thread is started which initializes the BLE and starts scanning. Trying to start the BLE thread first and then setting up the WiFi services gave continual reboots.
The NTP client is a low level time client based on https://www.arduino.cc/en/Tutorial/LibraryExamples/UdpNtpClient Attempts to use the ESP32 SNTP support resulted in exceptions when the BLE stack was initialized. To this was added the tz parsing and the LittleFS support from ESP-01 Timer Switch with TZ and Daylight saving adjustment
The current code only starts a BLE Scanner. The ESP32 RF Coexistence docs suggest you can also open a BLE connection. This has not been tested as the existing projects just scan to pick up the data broadcast.
This tutorial has shown how you can run both BLE and WiFi services together on an ESP32 C3. The code size requires using the Huge (3MB) Partition scheme instead of the default 1.2MB APP and 1.5MB SPIFFS partition. The WiFi services tested were simple WebServer, simple NTP client and a Telnet Server. Only a BLE scanner was tested, although the ESP32 documentation suggests you can also make BLE connections. In principle other ESP32 boards could be used but testing on an ESP32 Sparkfun Thing was not successful.
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