Tick tick, boom gate opens!
And by boom gate I am referring to the Kogan.com office car park boom gate. Kogan.com office parking spots are a scarce resource, but the staff members that are lucky enough to have an allocated spot aren’t always using them. Most days there is enough space for other staff members to utilise the parking spots, but there aren’t many remotes to open the car park boom gate. Is there perhaps a way to remotely open the boom gate by using the Kogan app only, without needing an individual remote?
During the recent hack day, team “Kogan Boom” took on solving this problem. We also managed to surprise and perhaps thoroughly confuse some passers-by when we were testing our solution and randomly opening the boom gate from the comfort of the office. This project had everything; electronics, hardware, software, app integration. It was a fun action-packed day for the team and everyone got to contribute.
The Boom Gate project comprised of three software systems:
The Boom Box: An ESP32 wired into the physical RF remote control for the Boom Gate. These remotes are in short supply and why we wanted to build the project in the first place!
IoT Cloud: We used AWS IoT Core to register the ESP32 as a ‘Thing’. AWS IoT made it simple to generate the MQTT authentication certificates that were copied to the Arduino code running on the ESP32. We created pub and sub topics via AWS MQTT for which to issue commands to the ESP32 controlling the gate and for the ESP32 to communicate back.
Web App: A mobile app and web service that enabled authorized users to toggle the car park Boom Gate. Instead of registering this service like another ‘Thing’ - we used AWS boto to publish the message to the MQTT topic and generated a service account for authentication with permissions to publish.
Overall, when a logged in user hits the ‘Open’ button in the APP, a POST request is made to the web service which then pushes a message to the MQTT topic. The ESP32 subscribes to the same topic, receives the message and toggles the PIN which connects the circuit on the RF Remote Controller and opens the gate. The RF signal from the remote conveniently reaches the Boom Gate from within the office!
The Electronics
The electronics part of the project included connecting a physical car park remote to a wifi enabled Arduino chip, requiring some delicate soldering work. Well it just so happens that Hanna used to do soldering professionally! She had a summer job at an electronics factory a long time ago and got to do a lot of soldering. Hack day impromptu workstation pictured below. It is good to note that neither staff nor equipment was harmed during this process.
The ESP 32 Arduino chip was programmed using the Arduino IDE. We connected the ESP32 chip using USB Micro cable to our laptop. Testing whether the code is working or not is one of the most challenging parts. Using the IDE, the code is then uploaded to the chip. Then using a multimeter, we checked whether we received the expected HIGH/LOW signals on the right port.
Using the pin diagram we picked pin 5 to write high/low. Thee ESP32 chip was then soldered to the remote which requires a HIGH single to open up the boom gate. Since ESP 32 is WIFI enabled, therefore the code running inside the chip subscribes to relevant AWS Iot pub/sub channels and listens for the relevant incoming messages from AWS ref. https://iot-esp32.workshop.aws/en/module3/configure_esp32.html. Based on the message from AWS, which in our case was plain “open”, a HIGH signal is sent to the remote which then opens the Boom gate. We didn't need to program anything for closing the boom gate as this was handled by the boom gate itself.
The Mobile App and Web Service
Mobile app section of our team worked on the design and implementation of a new “Kogan Boom” app feature, which is only displayed for Kogan.com staff. There is a button to open the boom gate. Since the boom gate closes automatically, a specific button to close it was not needed.
When a user taps the ‘OPEN’ button, a web request is sent to the web server which then publishes a message to the AWS IoT MQTT topic that the ESP32 is listening on. We achieved this without needing to register the web service as another IoT ‘Thing’ and instead used the AWS Python boto library to publish to the topic via a service account. This was fairly trivial once we figured out the command to run!
The service account we created was given the AWS IAM access policy: arn:aws:iam::aws:policy/AWSIoTDataAccess so that it could publish to the IoT MQTT queue.
Putting it all together
The finished hardware prototype turned out to be a rather sketchy-looking box full of electronics and wires. Some of the time the box was even ticking! Perhaps the name “Kogan Boom” was not ideal after all?
Our hack day project came together nicely in the end and we were able to open the boom gate using the button in the Kogan.com mobile app. All in all, it was a successful hack day full of collaboration, new learnings, laughter and some very tasty donuts! We are very much looking forward to the next one.
