Period correct radio head unit (work in progress)

[GabrielGab]

Hello everyone, I've started working on something fun and I could use your feedback! 

I had been looking for a head unit for some time and started to become frustrated with the available options. Original BMW radios from the era are now getting silly expensive (in Europe, anyway) and the functionality is lacking by modern standards. There are aftermarket "retro" options, but they really aren't that perfect of a match for BMW's design language of the era. Not to mention that they are still missing many features we take for granted these days, and are also expensive for what they are. 

So... I decided to design and build my own, and here is what I have come up with. The front panel's texture, switches, and knob match the 80s-90s BMW design perfectly, and the small screen that is incorporated is deliberately small so that it does not look out of place in these classic models. 

I'm working on the graphical interface for the software which takes inspiration from the first BMW OBC monitors which appeared with the e38 7 Series in 1996 (slightly later than our models, but still old enough not to look inappropriate from a design perspective.) I'm also planning an alternative, purely monochrome orange/black mode if the user would prefer to have an even more classic appearance. 

As it stands we have a working prototype with a few technical issues left to solve relating to the audio processing and power supply. 

Any suggestions from the community will certainly be helpful in further development, I would love to know what features you guys find most useful in a device like this and what you find irritating about the currently available solutions. Let me know what you think! 

[Shawn D.]

That's pretty neat!  I'm looking forward to how this progresses.

[harrypalmer]

I second Shawn D.

I have been putting on hold for two or three years now, sending my own BMW E28 CM5907 Alpine Cassette Player Radio similar to this: https://www.ebay.com/itm/235733287588 to have it fix. There's a company in San Diego (escape the name) that charged $350 plus shipping (both ways) to fix the volume and replace tape belts.

Now regarding your concept, I sadly ended up replacing my OEM 1993 Volvo unit for this run of the mill and out of place Sony unit: https://www.crutchfield.com/S-WuRc4iEmSba/p_158N5300BT/Sony-MEX-N5300BT.html?XVINQ=GZ0&XVVer=16UP&awcr=638145609574&awdv=c&awnw=g&awug=9028775&awkw=pla-668506400054&awmt=&awat=pla&gad_source=1&gad_campaignid=18589620441&gclid=EAIaIQobChMIodioiuSLkwMVkNrCBB1R_yAmEAQYASABEgIBcPD_BwE. I disliked the fascia and I still do somehow. I mention it, because some of its features (which is what you are requesting to know) actually have grown on me and I truly appreciate them. Below are some:

- BlueTooth capability a must. (And this Sony unit picks up the signal really quick and automatically)
- Your concept radio's Fonts, Numbers, Color (digits) should be similar and period correct closer to the CM5907 Alpine, and not the later BMW 1990 versions which (to me) look more modern but "feel cold" and out of place at least it would in my E28 such as this https://www.ebay.com/itm/147115993761?
- I usually don't accept or make phone calls while driving so I would not care for a hands-free.
- Voltmeter is monitored frequently so I think that would be a plus to have
- Out-door temperature very handy
- Ability to read, seek and rewind displayed music/artists/songs
- Dimmer for front fascia display light
- Volume Fader (four ways), and ability to equalize songs if possible
- Aux jack could be very helpful as well
- USB A, B, C or any other type of plug for charging a phone would be really neat.

Wish you luck and prompt success.

[vinceg101]

I agree this looks very promising, so long as the final cost remains "reasonable" (by that hopefully less than the current modern Blaupunkt or Alpine retro units; or if possible, matching with better features).

I also agree with Harry Palmer in that there should be the full array of input options:
-Bluetooth
-AUX (on the front face and maybe an option to have a rear connection for a remote jack in the glove box)
-USB (A and/or C, which means you have to have some kind of OS that can read & navigate tracks if you have USB-A sticks)
-Microphone (for telephone. I agree that maybe HFT isn't a 100% priority but it would complete the package)
-Remote CD (While this is way down on the priority list, wouldn't it be cool to have a DIN input to use the BMW/Blau/Alpine trunk mounted CD players? I have no idea what this means to the programming and hardware, and you would have to chose which generation CDP & DIN to include. Again, not important but it might really set this HU apart and get more retro interest.)

Features:
-FM/AM/Weatherband (obviously, which means an antenna input with trigger)
-4 RCA Channel Signal Output (for external Amp & speaker setups)
-4 Channel Speaker Output (having an internal amp powerful enough to run 4 speakers should be standard making an external amp not a requirement)
-Balance & Fader (L-R/F-B), I would stress that these should be manual controls knobs/buttons and not a screen interface
-Bass & Treble manual controls (obviously)
-Steering Wheel Remote control connections (not a must, but might be nice)
-HFT (as stated, Hands Free Telephone/BT capability isn't an absolute, but would complete it and make it competitive with other HU's)
-USB Power Charging (both A & C, but C is a must if you can only do one)
-Screen Color (should be standard BMW orange, obviously, but should also be capable of doing positive/negative backgrounds since it's easier to read with black digits on an orange background in bright light situations. Also the screen has to be matte finish. Full stop. This has been the major failure with most aftermarket units.)

As far as other features that go beyond the usual Audio HU functions, I would urge caution about trying to include too many engine systems components. I would agree than maybe some kind of battery and/or electrical system monitoring might be handy since these seem to be lacking from BMW (e.g. Voltmeter and battery level). Other than that, I wouldn't want to be doing endless scrolling for information on a small screen. Maybe this keeps the onboard OS and hardware simpler and makes your goals more achievable (?)

I think that covers it. If it comes to fruition and has all the above, I would consider replacing my current vintage Blaupunkt SQR-88 Woodstock.

Good Luck!

[Tiit]

Very interesting, but one important function is missing. It doesn't play cassette. Am I the only one who still listen cassette? 

[stuartinmn]

Are you adapting a new face plate to some commercially available stereo, or are you building the entire thing from scratch?  Either way, it's impressive work.

[4DSC]

I have the retro modern Blaupunkt sqr 46 and one of my biggest gripes with it is at that price point, the button feel/action is terrible and cheap feeling comparing to the real vintage Blaupunkts I've had. So that's my one point of feedback that hasn't been mentioned, if that kind of thing is important to you.. invest in some buttons that are satisfying to press

[vinceg101]

Very interesting, but one important function is missing. It doesn't play cassette. Am I the only one who still listen cassette? 

I bought my SQR-88 just for this function (that and the front panel AUX input). Of course I've yet to record any cassettes...