SMS4IOT for RTL8720DN BW16 Demo 5GHz and 2.4GHz

Write firware into rtl8720dn

Download latest rtl8720dn BW16 firmware (sha256sum km0_km4_image2.bin d99e804815d1583ed946db06a7c252a14dc5804d8114cb57c49fcb6108670bbb ) and upload to rtl8720dn module at address 0x08106000. If you are looking at this page, I expect you already know how to do this (while grounding LOG_TX pin, shortly ground and release EN pin. Then use Realtek ImageTool connected to LOG_TX/LOG_RX pins to upload firmware file to 0x08106000.).
- Solder 0.1uF + 10uF caps between VDD33 and metal shield (same as GND)
- Solder 1uF between EN and metal shield
- Solder pushbutton (1) between EN and GND
- Solder pushbutton (2) between LOG_TX and GND
- Connect GND to GND on USB-SERIAL
- Connect LOG_TX to RX on USB-SERIAL
- Connect LOG_RX to TX on USB-SERIAL
- Connect VDD33 to 3V3 on USB-SERIAL
- Plug into computer USB
- Start up Realtek ImageTool.exe and Chip Select RTL8721D; select COMX corresponding to USB-SERIAL; check fourth checkbox on left and browse to the firmware file you downloaded above; and finally enter the address 0x08106000. Chossing this address (OTA2) gurentees the new firmware will be run.
- Press pushbutton 1 and 2. Release 1. Then release 2. Module is now in download mode.
- Click DOWNLOAD
- After sucessfully completed, Press pushbutton 1 momentarily to reset module
- You are done (happy to share Gerber PCB files)
Note: I found through extensive experimentation that if you are using just the plain BW16 rtl8720dn module, a 1uf capacitor from EN pin to ground may be needed to ensure predicable behavior (in addition to proper VDD33 pin bypass). Though not recomended, I have found the 100ma 3.3V supply from CP2102 USB-to-serial modules sufficient to power the rtl8720dn in most cases.

Install SMS4IOT Manager app on your phone

Android
- Download android app
  sha256sum s4ii.apk 228da22e2aaf2b86da8c5e59a9670a25e51c54e0312ecf332af4122586be9872
- Various warnings will pop-up since this is BETA software. Skip or acknowledge these warnings to eventually install and open the app. If you do not feel comforable with this, do not continue. Eventually, we plan on listing the application on the Google Play store.
- The application will require Location and Camera access under permissions.
- The mobile phone must have Internet access and does not have to be the same as what the rtl8720dn module may automatically choose to communicate over.

Be near a non-encrypted (no lock symbol) WiFi hotspot. This could either be one you setup and control thats just OPEN or any public hotspot, e.g., cafe, hotel, resturant, plane, airport, school, business, bar, urban area, etc. SMS4IOT does not require password information but does require the hotspot not be WEP/WPA encrypted.

Using the setup you used to program the device, connect to the LOG_TX/RX serial port of the device at 115200 baud with a suitable terminal emulator such as "screen" on Linux. You should see occaisional activity.

Power cycle the rtl8720dn module. The module will start by scannng for a non-encrypted hotspot. Once found it will start communicating via DNS to our autoprovisioning server. If successful a 4-byte ID number is assigned to your device along with a key used to provide access to our SMS4IOT gateway. Your device will also generate its own private key shared with no one that will be used to securly communicate with your android application. Our gateway cannot read any messages.

Enter "qr" in your terminal. This will display a QR code for your mobile application to scan. Adjust terminal screen size and enter "qr" again if needed to get the full QR code on the screen. Start the SMS4IOT Manager application on you mobile device and tap upper right hand menu icon and tap "Add Device". The camera should turn on so that you can scan the QR code.

In a few seconds an entry for your device should appear. If rtl8720dn has succesfully communicated with our SMS4IOT gateway, in a minute or two, the mobile app should turn the entry for this ID green and eventually fill it in with data from the rtl8720dn module. All communication between rtl8720dn module and mobile application in end-2-end encrypted with the key generated inside the module and transfered to mobile app via QR code.

Each item on the screen looks like:

10000039
V0.033 OFF L 3113mv Test_AP 3:days 5:hrs
40:e3:d6:da:be:70 -35
40:e3:d6:da:98:f0 -40
40:e3:d6:da:99:b0 -55

First line is device ID number (hex) assigned at autoprovisioning. Next line is firware version, relay state (PA14), input pin logic level for sensing (PA30), ADC (PB3) reading, current hotspot being used, uptime. The next 3 lines are the top 3 access point BSSIDs near the device in order of signal strength. This information can be used with Google to determine the latitude and longitude of the device.

Google geo api: https://developers.google.com/maps/documentation/geolocation/overview                        
Create fname.json:
{
  "considerIp": "false",
  "wifiAccessPoints": [
    {
       "macAddress": "40:e3:d6:da:98:90",
       "signalStrength": -20,
    },
    {
       "macAddress": "40:e3:d6:da:be:70",
       "signalStrength": -25,
    },
    {
       "macAddress": "40:e3:d6:da:98:f0",
       "signalStrength": -25,
    }
  ]
}

Then do:
$ curl -d @fname.json -H "Content-Type: application/json" -i "https://www.googleapis.com/geolocation/v1/geolocate?key=YOUR_API_KEY"

Firmware notes:

PA14 output controlled by sending text to device "setrelay on" or "setrelay off". Shown as ON or OFF.
PA30 input sensing logic level and shown as H (high) or L (low)
PB3 is analog input to ADC and ranges from 0 to 3300mV
PA25 = SCL and PA26 = SDA. If you connect a SSD1306 128x64 I2C display to these pins, the firware will automatically detect it at boot and display text you sent from the app on it as well as ID and currently used hotspot name.

Via the LOG_TX/RX will show various values as well as "stat" showing current status.

reset - reboot
status
rescan - re-scan for hotspots
qr - display qr code for mobile app to get device id and keys
set relay on|off
set debug 0|1
set 0ssid clear|ssid [wifipass]  - this tells the devices to first try this ssid/pass on boot. If it fails, device will revert to scanning for a hotspot.  Useful for lab testing and fw upgrades.  "clear" disables this feature.

If the hotspot being used is completely open, such as one in your laboratory or your controled environment, the firmware will look for an updated version and start downloading it automatically. Version can be displayed with "set" command and at device boot if SSD1306 display is attached.

SMS4IOT MQTT gateway with Home Assistant example here

NEW Beta ESP8266 firmware for 2.4Ghz only. No 5Ghz WiFi so not so interesting.