IoT App Development Questions (MQTT)

For my summer internship I’m working to develop an augmented reality application at an engineering firm. The basic functionality is pulling data off of an HMI via OPC, or maybe some sort of Modbus situation, then overlaying that information onto the engine itself. It’s a large stationary generator set, not a car engine.

The HMI will plug into a heavily industrialized Raspberry Pi, which will run some basic Python script to interpret the data, then send the data to a phone via MQTT over a local network.

I just wanted to ask if anyone here has experience using MQTT. I have a lot of support from some really talented people to help me get everything working right up until wireless technology gets involved. At that point I’m pretty much on my own.

I’ve been trying to get a very simple proof of concept working based on this tutorial on the Raspberry Pi forums

It’s really basic, but it’s also pretty old, so I don’t think I’m going to get any help on there. I know it’s in swift, and Xcode, but I don’t really need help with that aspect anyway. Cross platform functionality is going to be important eventually, but for the time being I’m trying to build stuff in iOS because I don’t even have access to an Android Phone right now.

I just want some advice for troubleshooting and getting an MQTT connection going between two devices. Given all the IoT content on the YouTube channel as of late, I’m hoping there are some people who have overcome some technical hurdles in this area and I’d appreciate any insight you guys can offer.

I am also open to maybe changing course in terms of protocol if anyone has any better suggestions.

I’ll do my best to share my progress too if anyone is interested.