PoloGreen92

Here I am thinking about how cool a SNES emulator with a Pi would be and then I see this.

LWesthaver

FYI, I just did a quick estimation of the parts needed to build the Comvette head unit and it looks like this:

$33.00 - Chassis: base-plate, face-plate, overlay
$6.00 - Hex Standoffs
$1.00 - Countersunk screws
$1.00 - Pan head screws

$5.90 - Volume ****
$2.50 - Volume Pot

$6.00 - 3.5mm Stereo Male to Two RCA, Black, 12 Feet
$9.98 - Radio Wiring Harness for General Motors 1978-1991

$8.47 - USB Panel jack
$5.49 - USB 2.0 A-Male to B-Male Cord - 10 Feet

$59.99 - GeeekPi 5 Inch Capacitive Touch Screen 800x480 HDMI
$15.99 - HDMI ribbon cable 10cm, Std. Female to 90 Degree Male
$10.83 - 10 ft Flat High Speed HDMI Cable
$14.00 - USB ribbon cable 10cm, USB A to 90 Degree Micro USB
$5.17 - USB 2.0 A Male to A Female Extension 10-Feet

$6.00 - Misc. screws, washers. nuts etc.
-------------
$191.32

This only the head unit. It does not include the other parts needed to create a complete system. The head unit provides a drop-in chassis to replace your BOSE head unit. It provides a way to plug into the car's existing BOSE wiring harness for sound and power. It's up to you to provide the computer to drive the video and audio.

Tempest302

His plasma cutter is designed to handle manufacturing custom auto parts, not sure the closest tolerance it is capable of but the setting I saw him using was 0.00028 of a inch, which is far more then this would need. Not sure how much a per unit cost would be with aluminum versus acrylic but a) I had access to it and b) I figured an anodized aluminum would look good.

As for making the kits, I imagine if you made some plug and play kits with all the wiring, the Pi with the software preloaded, and some step by step instructions that the kits would be at least mildly popular. Ebay or the WTS forums here could be a good place to sell them. This would cut down on how daunting the project feels to people without a lot of experience in custom wiring or similar fields. I feel comfortable with my ability to install the system based off of your blog but I have a minor in electrical engineering and have done similar things. In fact, I am working on custom fabbing sport seat wiring for my 90 sport seats due to an inability to find replacement parts. My opinion is you have done the hard part between finding compatible parts and writing the custom code for the Pi. I am going to try to make it work in my 90 despite the differences between the boses systems since my theory would be that all the differences are in the hardware I would be removing with, at worst, maybe a need to change the output single strength up or down if the bose speaker amps are used to a different power setting. I can't imagine the speaker and amp hardware are different enough that they would require any sort of radical redesign of your system, I mean at a certain point a speaker is a speaker. It should just be one black box connecting to another black box with minor output signal changes. I think.

Final thought would be, if you end up trying to make a go at making kits, adding in features like wideband o2 sensor and/or temp sensor reading and logging.

Edit: just read you wanted to add sport seat control. If you want, when I complete my custom sport seat harness I can send you what I did(switches, amps, volts, etc) , might help with figuring out how to wire it up. I would think it should just be relays in place of the rockers.

Edit Redux: Did some more research into how you would go about connecting the comvette to the sport seat controls. Looks like its going to be two DPDT relays wired to mimic the center off function of the OEM rockers in conjunction with a micro controller for relay control. Found this site: https://makezine.com/2018/03/19/cont...tronic-relays/ that lists some available micro controllers for the Pi if that helps any. I also have a diagram for how to wire the relays but its on a different machine. All in all, it doesn't look that complicated outside of GUI programming on the Pi though the relays might end up costing a not insignificant amount.

CGretired

This is a cool project. I own a 91 and will be curious to see if this can be adapted.

Space387

Aside from a rasberry pi unit would there be anything else we would have to provide to replace just the head unit and retain the tuner and 4 amps that came with the car? I am seriously considering this for a replacement of mine.

LWesthaver

Tempest, thanks for the comments. I have removed all of the wiring and extra stuff from my Sport Seats in preparation for the eventual connection to Comvette. Here's a diagram of the simplest way that I've seen to control (forward/reverse) the recliner and bolster motors:


A pair of SPDT relays should do the trick. I'll need a pair for the recliner motor and another pair for the bolster motor. I'll also need a MOSFET to interface the Raspberry Pi to the relays. But it should be pretty straight-forward.

-Wes

LWesthaver

Space387, I'm not sure what you mean by "retain the tuner". In the early C4's the tuner is part of the head unit. So when the head unit is pulled, the tuner goes too. That's why I've incorporated a new FM Radio module into this project. Essentially, I only re-use the BOSE amplified speakers and the existing wiring harness connections.

All of the parts I've used so far are listed here:

Comvette Components

I've got to say that one of the most important aspects of this project is power management. Computers (like the Raspberry Pi) really cannot tolerate having their power turned off without being shut down properly first. This page describes my approach to dealing with the problem:

Comvette Power Manager

I know that it seems overwhelming sometimes when you consider all of the parts required to build a system like this. Maybe I should offer some pre-built modules like the power manager.

If you're interested in building something like this, grab a Raspberry Pi, monitor, keyboard and mouse and download the image file from my website. From there you should be able to at least get Comvette up and running and see what you think of it.

-Wes

Space387

Wes in the 1990-96 cars the head unit is simply an oversized IO panel. The preamp, FM tuner and I think a few other features are in a separate module labeled a tuner. I cant seem to find documentation on it but my next day off I can try to give you the pinout for the input and output plugs. I have a spare tuner and 2 spare head units in pieces as they where used to refurbish my current one.

auburn2

Can you do balance and fade adjustment between the speakers?

LWesthaver

Currently, No.

I decided to leave that feature out as I found that I never used it in the old BOSE system.

LWesthaver

Your avatar confused me. It looks like an early C4 which is the audience for my Comvette project. Do you have an early or late C4?

If you have wiring diagrams for the late C4's BOSE system, it would be great if you could post those diagrams. I'm not ready to tackle a new project but I would like to start understanding the differences between the early and late C4 BOSE systems.

-Wes

Space387

It is a 1990 so the body of an early car but the dash of a later C4. I have searched far and wide but cant seem to find schematics of any kind displaying the 16 wires from the head unit to the control module(tuner)

LWesthaver

I'm pretty jazzed! My Comvette Project (diy BOSE head unit replacement) was featured on the Ponoko.com website today:

Spot The Laser Cut Parts In This Car

I think they did a nice job of describing the project.

-Wes

RockyL32

Will the pie3B plus work for this?

LWesthaver

Yes. That's what I currently have in my car.

Space387

I have looked into diagrams but nothing to show the internals or the bridge from head unit to the tuner for a 1990-1996. What I have noticed is that the output from the tuner is factory GM for the period and you could just run a 2.5 foot extension and adapter to under the passenger side dash to achieve putting this into a newer vette.

xrav22

What does this mean "It's up to you to provide the computer to drive the video and audio" I will be looking into this but my Bose Amps are gone so I would need an amp for the speakers.I just don;t understand the line above.
Thx

LWesthaver

With a little experimentation you might get lucky and find out that the later C4 BOSE systems drive their amplified speakers with "line-level' audio. If that is the case, you might be able to remove the BOSE head unit and the tuner box and replace it with a system like mine. This is purely speculation since I don't have a later C4 model to work with. It would be great if someone would run with my Comvette Project and adapt it to the later C4's.

-Wes

LWesthaver

Sorry for the confusion. When most people think of a "head unit" they think of a complete audio/video/nav etc. system in a chassis that can be installed in place of your original factory radio. But the Comvette system isn't like that.

The Comvette "head unit" is only a control panel that has a volume control, a USB jack, a touch-screen, several connectors that plug into the car's OEM wiring harness and several long signal/control cables. These cables can be run to another location in your car. In my case I ran the cables along the transmission tunnel into the rear passenger side storage compartment.

So essentially the Comvette system is a split system. The control panel is mounted in the dash and the electronics (Raspberry Pi computer, power manager, USB hub etc.) are located elsewhere. If you are wondering why I did it this way, well, I wanted to have the electronics accessible so that I can make hardware changes and apply software updates easily as the system evolves.

To address your situation: Since you no longer have the BOSE amplified speakers, you would need to add a power amplifier to take the line-level output provided by the Comvette system and amplify it to drive your standard speakers.

I hope this clarifies things for you.

-Wes

Tempest302

Wes, Sorry it took so long to get back to you, its been busy over here with work and I started some classes.

Thanks for this, might have to try it as I removed my radio it is possible that someone already removed the tuner. Haven't yet started digging around to see if its there or not but its on the list.

Question about where you plugged things in, it sounds like your system still uses the tuner to interface with the speakers? I can't find good diagrams for the radio system so its been a pain. It looks like the speaker outputs come not off the head unit but off the tuner box. Is that correct? My radio is completely dead and missing plugs so I cant test anything.

To add on to your last quote, you are saying in a system sans tuner and bose system, the comvette output could put directly into traditional amplifier to speaker configuration?