I've spent a lot of time playing around with building a sound unit, so there hasn't been a lot of updates to the build. I never planned to use a proper sound kit, because I was never convinced they sounded good enough to be worth the price, so I didn't design a space for it in the truck. This winter I found an open source engine sound project, using an ESP32 microcontroller to play multiple sounds together with the engine sound. It's also in control of the ESC signal, so the truck has a simulated inertia, with slow acceleration and coasting.
I liked it better than the TBS/Dasmikro/Benedini micro sound unit out of the box, so I started to play around with modifying it to my use. I've now coded in an approximation of an Allison automatic gearbox, so it sounds like it's changing gears, and I've added recordings of two Norwegian sirens (a fast one and a slow one).
Because it's now in control of the ESC, I was also able to code in a function that lets me switch between reverse and forward mode with a separate transmitter switch, while keeping the brake function of the ESC. It works by sending a "double tap" of backwards input to enable reverse mode, and staying in backwards range when the switch is flipped, and makes sure to blip the throttle in normal mode when coming off the brake, to ensure it doesn't accidentally enter reverse mode when it shouldn't.
This is what it currently sounds like:
https://www.youtube.com/watch?v=9ex9XDmr8_Q&
Short test drive:
https://www.youtube.com/watch?v=qc6XIntvkuc
Youtube channel of the original author of the project:
https://www.youtube.com/user/TheDIYGuy999
And the original code:
https://github.com/TheDIYGuy999/Rc_Engine_Sound_ESP32
My poorly documented and highly specialized fork of the code, for anyone curious:
https://github.com/Wombii/Rc_Engine_Sound_ESP32
I managed to squeeze the controller and amplifier under the rear bench in the cab. The amplifier has a volume pot sticking out under the cab floor. Well hidden, but usable without opening the cab.
I also made a custom telemetry screen for the transmitter. Here's a shot of that, with an overview of my control layout.
After some digging, I was able to find the correct SCBA fixtures / rear seating. Here's a nice reference pdf from Rosenbauer:
https://www.rosenbauer.com/fileadmin...A_fixtures.pdf
1mm + 2mm styrene sheet with the Tamiya seat as size reference:
Mounted using magnets and shims
Most of the interior is now painted. Still needed are some hand rails, door panels and rear bench. Very happy with how much the locker box between the front seats looks like painted metal. I painted the seats with a brush because I wanted a slightly worn look, but I went a bit too rough, so I might have to do another coat.
Warm white cab dome lights when ignition is off
Low intensity red lighting when ignition is on
