AWS-IoT-Demo

Here is a fun way of experimenting with AWS-IoT on a Commercial-Off-The-Shelf(COTS) hardware running OpenWRT Linux and aws-iot-device-sdk-cpp-v2 based aws-iot-pubsub-agent. Custom built linux image for GL-MT300N-V2 pocket router allows you to configure aws-key/aws-certificate/aws-endpoint/publish-subscribe-topics and custom event-trigger-scripts so that you can see the effect of publish/subscribe messages having physical impact on tangible realworld components like LED-lights/switches as shown in the video below.

Setup diagram for overwriting OEM firmware of GL-MT300N-V2 router

Preparation

1. Download this openwrt based custom firmware for GL-MT300N-V2
2. As shown in the picture above, connet your browser-pc to LAN side network of the pocket-router and power it ON, with OEM firmware, webUI of the pocket router is accessible at ip 192.168.8.1(note: after overwriting OEM firmware, webUI will be available at ip 192.168.20.1).
3. Overwrite OEM firmware of GL-MT300N-V2 with custom firmware downloaded in 1st step(ensure that keep-settings is disabled so that we start with default factory settings on next boot)
4. After reboot, webUI of GL-MT300N-V2 will be available at ip 192.168.20.1 on LAN interface side
5. Userename and password for login page are root/aws-iot-demo(later change the pw to your own using openwrt-webUI)
6. Connect Internet to your GL-MT300N-V2 device by connecting it's WAN port to your home-internet-router or through wifi by specifying the ssid/key under Network-->Wireless-->radio0-->Scan setting
7. Login to your AWS-IoT Core Console, download new device certificate and private-key pair and ensure that your security policy for topic/test/topic* is set correctly for Policy-Action: iot:Publish/iot:Subscribe/iot:Receive/iot:connect(also notedown your endpoint) - Details on how to configure certificates and policies are documented in my other blog
8. Upload device-certificate and private-key to your GL-MT300N-V2 using webUI menu AWS-IoT-->Upload Device Cert and AWS-IoT-->Upload Device Key (note:Thoug clicking submit button uploads the Device-Cert/Device-Key files correctly, but there is no success message given to the user as feedback - I plan to fix this in the future by showing a success/fail message)
9. Under AWS-IoT-->Service Settings-->Endpoint set your aws endpoint(e.g xyz.abc.amazonaws.com) and click on Save & Apply button.
10. To see if the connection to AWS-IoT-Core is successful, Open AWS-IoT-->Service Log and check the last line of the log shows something like - [INFO] [2024-03-17T10:57:38Z] [77ad3ce0] [socket] - id=0x77ad9650 fd=11: connection success.
11. Toggle the slider switch of the pocket-router and see if first LED on this router follows the state of slider switch position - this is an indication that your connectivity to AWS-IoT-Core and publish/subscribe are correctly working.

Demo-Example-1 Preparation and Configuration

As shown in the picture above, to repeate the 1st example, you need to prepare three GL-MT300N-V2 pocket routers by following steps 1 to 10 as mentioned in Preparation section above. In step-8 of Preparation section, ensure that all three GL-MT300N-V2 routers are uploaded with their own set of certificates and private keys and set three different clientID's as test-1/test-2/test-3 under AWS-IoT-->Service Settings-->ClientID (Note: In this picture, Internet to the pocket routers are provided through mobile-data-network using sim-card, but you could simplify this setup by connecting WAN port of all 3 routers to your home-internet-router or configure all 3 routers to act as a wifi clients to your home-wifi)

Demo-Example-2 Preparation and Configuration

Demo-Example-2 is same as Demo-Example-1, except /usr/sbin/led-power.sh script under AWS-IoT-->Service Settings-->Subscribe Topic Handler to be changed to /usr/sbin/usb-port-power.sh on all 3 GL-MT300N-V2 routers (This example uses, USB powered LED's similar to the one found here

Demo-Example-3 Preparation and Configuration

For this demo you will need a volume-control-knob and blink(1) USB based RGB-LED dongle. As shown in the picture above, 1st-pocket-router is attached with a volume-control-knob as event publisher and remaining two routers are configured as subscribers and they change the color of the usb-led based on published button event from 1st router. For this demo, following are the settings of all 3 units set through web-interface.

Settings of 1st unit(publisher)

1. AWS-IoT-->Event Settings-->Key Event MUTE Topic : test/topic_led
2. AWS-IoT-->Event Settings-->Key Event MUTE Message : {"powerstate": "toggle"}
3. AWS-IoT-->Event Settings-->Key Event PREV-SONG Topic : test/topic_led
4. AWS-IoT-->Event Settings-->Key Event PREV-SONG Message : {"ledstate": "red"}
5. AWS-IoT-->Event Settings-->Key Event NEXT-SONG Topic : test/topic_led
6. AWS-IoT-->Event Settings-->Key Event NEXT-SONG Message : {"ledstate": "green"}
7. AWS-IoT-->Event Settings-->Key Event PLAY-PAUSE Topic : test/topic_led
8. AWS-IoT-->Event Settings-->Key Event PLAY-PAUSE Message : {"ledstate": "blue"}

Settings of 2nd and 3rd units(Subscribers)

1. AWS-IoT-->Service Settings-->Subscribe Topic : test/topic_led
2. AWS-IoT-->Service Settings-->Subscribe Topic Handler : /usr/sbin/usb-status-led.sh

Demo-Example-4 Preparation and Configuration

This demo-example is not shown in the video, but as shown in the picture above, it uses 1st-pocket-router to publish the temperature read from usb-temp-sensor-dongle and the 2nd-pocket-router displays the temperature on digispark-attiny85-usb-to-i2c-display and the 3rd-pocket-router will operate the usb-relay based on its temperature-threshold and hysterisis setting.

Settings of 1st unit(publisher) - every 5 second it reads temp from usb-dongle and publishes to test/topic_temperature using usb-temper-read.sh script, -1 count indicates loop forever

1. AWS-IoT-->Service Settings-->Publish Topic : test/topic_temperature
2. AWS-IoT-->Service Settings-->Publish Interval Sec : 5
3. AWS-IoT-->Service Settings-->Publish Count : -1
4. AWS-IoT-->Service Settings-->Publish Message : /usr/sbin/usb-temper-read.sh

Settings of 2nd unit(subscriber) - displays received temperature value on to i2c based oled display(ssd1306 128x32)

1. AWS-IoT-->Service Settings--> Subscribe Topic : test/topic_temperature
2. AWS-IoT-->Service Settings--> Subscribe Topic Handler : /usr/sbin/display-data.sh

Settings of 3rd unit(subscriber) - compares the published temperature and controls the relay state based on set threshold and hysterisis

1. AWS-IoT-->Service Settings--> Subscribe Topic : test/topic_temperature
2. AWS-IoT-->Service Settings--> Subscribe Topic Handler : /usr/sbin/temperature-relay-control.sh
3. AWS-IoT-->Service Settings--> Subscribe Threshold : 40
4. AWS-IoT-->Service Settings--> Subscribe Hysterisis : 5

On 1st unit, when body temperature of usb-temper-sensor crosses 40degrees, Relay on 3rd unit turns ON and when temperature cools down to 35(or below), Relay will turn OFF

How to build the GL-MT300N-V2's binary for these demo examples

1. git clone --recursive https://github.com/hackboxguy/openwrt-wrapper.git
2. cd openwrt-wrapper
3. ln -s ~/openwrt-dl openwrt-dl
4. ./build-openwrt-image.sh -v 00.01 -b gl-mt300nv2-awsiot-demo -o v22.03.3
5. ls openwrt/bin/targets/ramips/mt76x8/openwrt-ramips-mt76x8-glinet_gl-mt300n-v2-squashfs-sysupgrade.bin