New GS

In the past week I started working on the new Ground Station. The problems I’m trying to fix are:

  1. I want a dedicated GS, not a laptop. For this purpose I’m trying a raspberry pi with a 7 inch display (the official RPI touchscreen display), together with a custom case, 2 RC sticks and various buttons. The reason is that a laptop is unwieldy, not bright enough in direct sunlight, tends to get busy with other tasks in the worst moments, doesn’t have a touchscreen (at least my current laptop doesn’t)
  2. I want a nicer interface that focuses on the main purpose of the GS – flying. The current one focuses more on editing the nodes of the quad.

So I started a new project, the GS2 using QT’s QML and a touch driven UI. So far so good, here are some screenshots:


The resolution is 800×480, a bit small TBH but enough for now. The display size is 7″.

So far the experience in QML is great, it takes very little time to build a nice, functional UI. It does require to build proxies for anything that has to be exposed from the C++ side to qml but that’s a good thing as it separates the UI from the logic.

The main things that I still have to figure out are:

  1. How to create a property sheet in QML. This is used to show the init params and configuration for nodes. This UI is generated in the current GS so there is no need to write custom UI for every node but just a description of the parameters in a json file.
  2. How to write the node editor in QML. Screen real-estate is limited and the node structure can get complex. One possible solution is to allow node groups. Basically take the IMU and low pass filters ang build a meta-node – a Filtered IMU – and treat that as a new node in the UI. Or group all the Navio sensors together in a new Navio Node and avoid all the current clutter. This is an interesting feature that deserves a few weekends.


The physical part of the GS – the case, sticks, buttons are still to be designed but I’m sure I can come up with something in a few weekends. The main parts will be:

  • A raspberry pi to drive the display and run the actual GS
  • An AVR to read the sticks, battery voltage and buttons. Could be replaced with another multichannel ADC and the RPI GPIO
  • A few analog sticks. I’m thinking to salvage the ones in my TH9x remote or buy a few of these or these
  • A RFM22B and 2 TL-WN722 wifi cards for the comms. This will be in a detachable module in the GS, connected by a usb cable so I can mount it higher or on top of my car.
  • LEDs, piezo speaker etc

I already have the rpi + display and the first version of the GS working, check out the video here:

All in all – a few months of work. I hope I don’t get demotivated.




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