'35 Flatlander

[MrNick]

Greetings from -34C Alberta. With the first deep freeze here I'm finding the hours needed to finish building & installing a head unit in a 1935 custom built truck on a '97 Chevy S10 4x4 chassis; a project started in 2011 and put on the road in 2023. I doubt it will ever be 'done'...

The head unit build was started a few months prior to my discovering Hudiy, and I'm thankful for your application: my python is marginal but I did have OBD and GPS working before the addition of the Carkit dongle and its live iPhone connection.

The unit has a Pi5 8GB 256GB M.2 with RTC on Trixie attached to a 10" HMI. All power flows via Waveshare 3S UPS configured to power up by a momentary switch latching relays that remain powered until commanded off by the Pi several minutes after the truck ignition goes to zero. Attached to the pi is a powered USB hub hosting the Carkit adapter as well as RTL-SDR and OBD2 connections. A buck converter charges/ isolates truck +13.6v from the UPS +12v and separate grounds are maintained on the truck and logic circuits.

The Pi/ Hudiy/ Carkit are configured/ working and I'm finishing up the wiring. The dash has been modified with a bigass hole and mounts have been designed, printed from PA6 and installed.

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[MrNick]

Time to smoke test.

[MrNick]

Design criteria:

1.) Parasitic draw when off is not permitted.
> RPi5 must disconnect when off; normal shutdown leaves the computer in 'low-power-mode'.
> HMI screen must disconnect when off; backlight remains on when connected to power.
> UPS must disconnect when off; LiPo batteries are not to charge when system not in service.

Operation:

2.) Manual startup with a demo mode bypass.

Momentary button pressed -> amber LED lights (13.6v truck active)
Buck converter powers up -> red LED lights (12v Buck out active)
UPS on switch activated -> blue LED lights (5v UPS out active)
RPi5 comes up -> green LED lights (Pi alive) (to do)

3.) Auto shutdown:

The Waveshare 3S UPS charges while discharging: being a smart device, internal voltages and current are available via python script. A Pi script monitors the supply voltage and starts timing down upon loss of mains. The Pi then winds things down and commits suicide by gpio.

4.) Manual shutdown:

Securely located Blue Switch of Death.

Hudiy.

5.) Pi starts -> scripts start -> Hudiy starts -> iPhone connects -> music starts -> happy place.

So far it performs as designed. Next step is to plagiarize a few scripts then add a second Bluetooth to stream tunes from iPhone -> Hudiy -> Kenwood bluetooth only amp + sub. 1kw of Tiesto & Mathame in a 1935 truck cab... I'm on my second sub... Right now it's wifi from phone to Pi then b/t to amp, but I'm thinking that's asking for trouble.