Lets get this party started…

We’ve been accepted into PiWars 2024! So, I think it’s time for an update.

Since our last post, Firefly has jumped from the Fusion 360 CAD world into the real world. (In other words, it’s been 3D printed and sprayed). It has been fitted with a radio control system and two motors and it can now be driven.

It spent last Saturday being driven around an obstacle course (sometimes rather too enthusiastically) by people of all ages at the Sidmouth Science Festival. During the day, the tracks unclipped a few times, and the driving sprockets came undone a few times too, but basically the robot stayed in one piece for the day. The only real problem is that the paint flaked off of the cab. In my view, if it can stand being driven by random five-year-olds, then it is robust enough for PiWars, where either our expert driver, or a Raspberry Pi will be at the helm.

I was also pleased to note that the batteries (it has three 18650 LiPos wired in series giving a total capacity of 3Ah at a nominal 11.1V) were nowhere near exhausted by the end of the day.

However, there are some problems.

• I am rather disappointed by the finish of the cab. The “glass” has picked up the layers from the 3D printed mould. Also, the paint edges are not particularly tidy, even though they were done with masking tape. Some paint mist has got inside the glass, and now (i.e. following the Science Festival) much of the paint has flaked off of the cab anyway.
• It’s also not possible to mount the speaker in the cab, as the glass prevents access to the nuts that were meant to be used with bolts to mount the speaker.
• But most significantly, there is not enough room in the hull for the electronics. When I did the design I planned for a robot control PCB that was roughly the same size as last year’s. I knew there would need to be extra electronics, (two extra motor drivers), but I figured I could save space by building a PCB. So far, I have not been able to get the necessary components on the PCB (without even trying to lay the board out completely).

I’m wondering if I should re-work the design to include a bigger space in the hull for a bigger PCB. And perhaps re-work the cab to make fitting the speaker easier and to remove the need to spray the vacuum formed cab. For now, no decision on the way forward has been taken.

You can find more information about Firefly here.