Once I disassembled the navigation hood of my 2004 Mazda RX-8, I discovered the wireless CarPlay/Android Auto receiver I wanted to install would not fit. It’s a few millimeters wider than the existing navigation screen and the bezel had no room to spare. I would have to cut something to make everything fit. Between the cheap device I could easily replace with another Amazon order versus Mazda interior trim piece, I prefer to cut the cheap device. I will take the receiver apart to look inside. Since I’m just scouting for trimming potential, this is not a full teardown.

Its enclosure was held with just clips, no fasteners. It was a matter of jamming enough opening picks into the gap to release a row of clips on one edge. Once that’s accomplished, remaining clips released easily.

It’s pretty minimalist inside, as fitting for a low cost device. Just a single main circuit board, the screen, and a few supporting components.

I had half expected a PCB antenna, but happy to see a short little thing glued to the case and attached to the circuit board with a removable connector. This potentially give me more options. Either in relocating this antenna elsewhere or replacing it with a different antenna in the hopes of improving reception. I will use this one as-is until I have a reason to tinker.

Looking at this antenna, I felt something was wrong and it took a few seconds of thought to realize what: when I look at similar antenna during computer teardowns, they’re always carefully placed outside of metal RF shielding. This device appears to have no metal shielding at all. In fact, now that I am looking for them, I noticed there were no label for make and model number and, most important for this discussion, no FCC ID listed. Is this thing even legal?

On the upside, the lack of metal shielding meant it’ll be easier to cut this enclosure backside to any shape I need to mount it in my navigation hood. And the lack of components meant I won’t damage anything on the way.

I saw quite a few unused provisions on this circuit board. The terminals labeled “-” and “+” are apparently provisions for a battery. I’ll be running this on car power so I don’t care. More interesting to me are two surface mount buttons that are not accessible when this unit is closed up. What are they for?

Down in one corner I see the embedded microphone and, a few centimeters away, a cable leading to the screen. I thought this might be backlight power, but terminals labeled with I2C style “SCL” and “SDA” tells me this is more than just supplying light. This is probably the capacitive touch controller.

Flipping the screen open, I could confirm it is indeed the touch controller. The good news is that capacitive touch digitizer is roughly the same size as the LCD, so they’re safely out of the way from trimming operations. The bad news is the front of this unit is a single sheet of glass bonded to the front of this enclosure. Given the price point I had expected a sheet of clear plastic, but it’s glass.

The only method I have of cutting glass is the “scratch a line and bend” method. I don’t have a handy diamond to scratch glass, though maybe one of my carbide tipped cutting tools can do it. More problematic is the bonded piece of plastic which makes the “and bend” part very difficult to do neatly. I’d likely shatter something else in the process.

Looking at this situation, I decided I couldn’t avoid cutting into Mazda interior trim piece. But I’ll try to minimize the damage. On the device side, I’ll cut away as much of the plastic as I could. Whatever is left (the glass and its plastic backing) will need only a narrow slot to slide in sideways.

A car’s interior is a pretty awkward place to work. As soon as I freed the navigation LCD assembly from my 2004 Mazda RX-8 dashboard, I moved my project to a flat work area. It was lined with a clean soft white towel to reduce chances of something getting scratched up.

I immediately unclipped the center speaker mesh, because that looks extremely fragile. I set it aside in a safe out of the way location. In hindsight, I didn’t need to bother. This large panel can be freed easily enough.

There are two buttons on this assembly, one on either side of the retracting hood and each secured with a screw. The retracting hood itself is an assembly I can unscrew as well.

The electromechanical assembly can then be separated from the large cosmetic panel.

I was encouraged by what I saw on the side. I can see the retraction gear mechanism and two details that would help me reassemble this later. First, the motor has a D-shaped shaft (round with a flat section) so the gear can be removed and reinstalled in the exact same place. Second, there is a small white mark on the gear for alignment with a similarly marked tooth on the track.

I also saw the retraction hinge is hollow, with a beefy ground wire through the hole on this side. This will help me route wires for my project. But all I see here is a solid grounding wire. Where is the wiring for everything else?

I found my answer after undoing the four screws (two on each side) holding the hinge in place, freeing the hood itself. Now I can clearly see a wide flat FPC (flexible printed circuit) handling the majority of electrical connections between the base and the hood. I can also access the two screws holding the hood lid.

Once hood lid was removed, I have a clear view of the retraction mechanism sitting behind the LCD screen. I would have expected the retraction mechanism to live in the base and not in the hood, but here it is taking up valuable volume inside. I also didn’t expect it to be controlled by the LCD circuit board, but I learned this was the case from RX-8 owner forum of others who have done this before. I had originally thought I could just remove everything inside the hood but, if I want to maintain the hood retraction capability, I’d have to keep the LCD circuit board for its little side function.

Removing the motor assembly allowed me to open up the stout metal shield protecting the factory navigation LCD screen. This shield is the destination for that beefy ground wire I saw routed through the hinge. Using my multimeter, I found three of the FPC ribbon cable connections had continuity to the beefy ground wire, but they were apparently not enough. It sure looked like Mazda engineers were forced to install additional grounding during vehicle development. I wonder what the problem was.

Speaking of problems, this section of the LCD circuit board has me extremely worried. Based on CAUTION! HIGH VOLTAGE! warning printed on the circuit board, big beefy components nearby, and thick wires leading to the display, I deduced this is for a CFL (compact fluorescent) backlight. My car was apparently too old for a LED backlight.

A high voltage transformer like this assembly will throw off a lot of noisy electromagnetic signals, the kind that would mess up a capacitive touchscreen. The factory screen is not a touchscreen so it has no worries on that front, and the stout metal shielding would have mitigated interference with other components. But I’m going to swap out the screen and keep this circuit board to manage the retraction motor, and this circuit might be trouble.

And that’s not my only trouble. After removing the factory LCD assembly, I measured its width at 177mm including the sheet metal cage. My wireless CarPlay/Android Auto receiver is wider at 190mm and would not fit in between mounting posts molded into the retracting hood.

In order for this to fit, I will have to cut something. RX-8 owners who posted their tablet installation procedures on the RX-8 forums usually cut these mounting posts. I hesitate to make destructive modifications to my car. I would much rather cut into the inexpensive receiver, because it would be much easier and cheaper to buy a replacement off Amazon if I make a mistake. But before I start cutting, I should look inside to see if there’s anything critical along its edges.

I bought a cheap wireless CarPlay/Android Auto receiver and preliminary tests show it should work well if I can install it in place of the factory navigation screen in my 2004 Mazda RX-8. This is not the type of procedure covered by Mazda’s official workshop manual. I would need to check the RX-8 owner’s forum at https://rx8club.com to see what others have done before me. One advantage of a twenty-year old car is twenty years of other people sharing their stories of tinkering with theirs.

Surprisingly, I didn’t find anybody doing the exact same thing. Perhaps standalone wireless receivers are too new for this DIY crowd? There were plenty of threads about CarPlay/Android Auto audio head units with the Metra kit, like this relatively recent example, but I’ve already decided I’m not going that route.

The closest matches were from people who installed a 7″ tablet in their factory navigation hood, as my new wireless receiver is basically a 7″ tablet. I found several threads and many of them referenced one of these two pioneers: one project installing a Samsung Galaxy Tab 2, and another project installing a Huawei MediaPad. Both of these were long threads with reference pictures and many good questions followed by valuable answers.

For connecting tablet audio to the car, later RX-8 came with an auxiliary audio input jack. Early RX-8 did not but this is a well-solved problem. People reverse engineered the audio head end circuit so we can get an auxiliary audio port that the car believes to be the optional cassette tape deck or minidisc player modules. Implementations range from an Arduino-based DIY solution to commercial products for sale. I bought and installed a Sylfex AuxMod Basic years ago, a product that has now been discontinued. Current-day alternatives include the GTA adapter kit.

My wireless CarPlay/Android Auto receiver came bundled with a backup camera. I’m going to postpone that project until a future phase but, when I get around to it, there are forum threads I can reference as well like this one.

Armed with knowledge, I opened up my toolbox and started dismantling my center console.

After I quickly reviewed everything that came in the box of this TTXSCAM T86 CarPlay/Android Auto receiver I bought via Amazon (*) it was time to power it up to see it in action. There were two test configurations. The first was powered by a solar charged battery and desktop speakers, the second round were powered by my car’s battery and output to my car’s speakers via an aftermarket audio input port. (Sylfex AuxMod Basic, now discontinued.) My observations are as follows:

The first thing I measured was the visible display area, and it was good news: it almost matched the size of stock navigation screen bezel. 4mm narrower in width and 3mm shorter in height, this is as close of a match as I could hope for. Mounting this inside the existing navigation hood would leave only a negligible black border.

When booting up, the screen displays this image which I think depicts a McLaren 720S. I want to change this image to maybe the Mazda logo or a picture of my own car, but I couldn’t figure out how. The device also emits a little musical chime on startup on both its internal speaker and the audio line-out port. I didn’t find a way to change or silence that, either. Neither of these boot-up behavior is a deal breaker but customization would be nice.

The device home screen has a few functions, the only one I cared about was “Android Auto”. Pairing it with my phone as a Bluetooth peripheral enabled Android Auto. Scrolling around Google Maps on this device, I found the system responsiveness to be merely acceptable. There’s a noticeable delay between input and response, and scrolling animations are chunky. It feels roughly on par with <$100 USD Android phones commonly sold with prepaid cellular services. I am optimistic the device’s sluggish response won’t matter, because if I want to do something like putting in a new address for navigation, I can use my (much more responsive) phone’s screen.

Once connected to my phone, this receiver will try to reconnect to my phone every time it powers up. I counted ~30 seconds between turning on power and projecting information from my phone. It’d be nice if this was faster, but ~30s should be fast enough for everything to be up and running by the time I’ve backed out of the driveway.

Speaking of which, I also did a quick test of the bundled backup camera. I just connected the wires, no mechanical mounting. The camera is just sitting on the floor looking at my feet. With the camera connected and the signal wire tied to input voltage (emulating the power line of an illuminated reverse gear light bulb) it only takes ~10 seconds between screen power-on and showing backup camera view. This is roughly on par with the amount of time I allow the engine to settle down to idle before shifting into reverse, so I’m also filing it under “would be nice to be faster, but probably fast enough” as well.

When using audio line out, to my car’s audio input port, I could control sound volume with the existing sound volume control knob or steering wheel controls. This worked as expected with no surprises.

Screen brightness is another story. The factory navigation system automatically adjusts screen brightness based on an ambient light sensor and a signal wire indicating if headlights are on. I can’t tell if there’s a brightness sensor built into this device, but it definitely doesn’t have the headlight state. I have to manually adjust brightness to fit ambient light. I neglected to look for this aspect when listing my shopping criteria, oops. I’ll have to see if this bothers me enough to make me pay for an upgrade.

I’m encouraged by the almost-perfect screen size fit, fast-enough startup time, and integration into existing volume control. I can probably learn to ignore the startup image and chime. I’m not so sure about screen brightness behavior, but that’s not an immediate deal breaker. This cheap thing is not excellent, but it seems good enough to meet my needs. Before I take my car interior apart, though, I should do my homework and study information available online.

(*) Disclosure: As an Amazon Associate I earn from qualifying purchases.

I wanted to add CarPlay/Android Auto capability to my 2004 Mazda RX-8 by replacing the screen of the ancient Mazda factory navigation system. I picked out a standalone wireless receiver with features I liked and a physical size that I hoped would fit. When my TTXSCAM T86 (*) showed up, there was a satisfying quantity of stuff in the box.

I immediately went to the manual (which called the device a T86MP5) and found it to be nearly useless. A thin booklet of 22 meager pages that didn’t cover basic information like installation or anything about the backup camera. I think I’m on my own to figure out most of this device.

It came with two sets of mounting hardware. One for the top of the dashboard, either by the included double-sided adhesive or four fastener holes. And the other is a suction cup mount either to the windshield or to the included a smooth plastic disc, also with double-sided adhesive. I will mount this device inside a piece of existing interior trim, so I won’t be using either of these mounting arms.

It also came with a 3.5mm stereo audio cable, and a power cable that plugs into the de facto in-car power source form factor that traces its origin to a cigarette lighter. The device end of this power adapter is a USB type C plug, but this adapter is not a full USB PD (Power Delivery) source. It only claims to deliver 5 Volts at up to 3 Amps.

Majority of the parts count are associated with the backup camera. Electrically, there’s a wiring harness long enough to run the length of the car, various zip ties and other cable management tools, even a roll of electrical tape. I didn’t recognize the red plastic pieces and had to search online to learn they are T-tap connectors. Further reading taught me I am supposed to use them to tap into the reverse light power wire, so the system knows to turn on the backup camera.

Mechanically, this package included a license plate bracket and associated hardware to mount the camera top and center above the license plate. I can’t use this directly as-is because the RX-8 has its license plate illumination light centered above the plate, and this mount would block that light with the camera. I will have to modify the bracket, or existing light, or get creative with something else.

I was charmed by the inclusion of a few tools. A tiny screwdriver to work with the small camera-mounting screws, and a large piece of orange pry bar for removing interior trim. Something I’ll be doing a lot to run the camera wiring harness through the car. Looks like a proper backup camera installation will be a lot of work. Fortunately, I can put that off until later. The next order of business is to explore how this receiver works with a benchtop test.

(*) Disclosure: As an Amazon Associate I earn from qualifying purchases.

I wanted to add CarPlay/Android Auto capability to my nearly twenty-year old car and as soon as I learned standalone receivers existed, I knew that was the direction I wanted to go. I started looking for a good candidate for installation inside existing navigation hood. It’s a little motorized retractable pod where Mazda housed the screen for the factory navigation system, and fitting into that pod will be the primary physical constraint. In addition to physical size, there are several other evaluation criteria:

Screen

Annoyingly, screen size is the next most important constraint, yet it isn’t something I can confidently determine. I want to buy a unit with visible screen area matching the factory navigation screen, so it fits perfectly in the original bezel, but the exact height and width are never specified. The best I can do is look for a “7-inch class” diagonal screen, excluding significantly larger and smaller screen sizes. I also excluded wide aspect ratio screens like this example. (*) A wide screen is a great idea for sitting on top of the dashboard, the intended use these standalone receivers. Showing more data without being too tall and blocking the driver’s view. But I want to fit into an existing 16×9 aspect ratio bezel, so those novel designs are out.

For the display panel, I personally prefer IPS panels for their color and viewing angles. Some units use a TN panel which will probably suffice. (The original navigation screen was likely a TN panel.) I don’t think they make VA panels at these small sizes, but they would also suffice. And finally, I’m not willing to pay the premium for an OLED panel here. Their stunning contrast ratio would be lost in the interior of a car, and there’ll be a lot of infrequently changing pixels risking OLED burn-in. Making OLED a poor choice for this application.

Most of these 7-in screens list their resolution as 1024×600. This is pretty low by modern screen standards, but it’s going to be mounted in a car further away than my usual computer and phone screen distance, so it might be fine. I’m confident it’ll be an upgrade from the factory navigation screen resolution! If resolution proves to be a limitation, I’ll come back and pay extra for a unit with a 1920×1080 screen.

[UPDATE: It would be nice if the device automatically dimmed the screen when dark. I forgot to look for that in my first device, it’ll be added to the criteria list if I shop for another.]

Touch Input

Capacitive touch technology has taken over everything, I didn’t see any of these receivers listed with a resistive touchscreen. My concern with capacitive touch is their sensitivity to environmental interference. A resistive touchscreen will only react to physical forces. A capacitive touchscreen might be affected by the plastic bezel, mounting hardware, or other electronics in close proximity. But given the lack of non-capacitive options I just have to give it a try.

Camera

Since these things are designed to sit on top of our dashboard, some (like the wide aspect ratio item linked above) integrated a front-facing dashboard camera. Since I want to bury mine inside the factory navigation hood, that feature would be useless for me. On a related note, several included either provision for a backup camera or comes packaged with one. This caught my interest. RX-8 rearward visibility is not great, and I’ve occasionally wished for a backup camera.

Audio

For audio output, these devices all have a little built-in speaker for when they’re sitting on the dash. Since I want to integrate it into my car, I want units with a line-level audio output jack. Some of these units can also act as a FM transmitter so we can tune in with the radio, which might sound better than the tiny built-in speaker but not as good as line-level audio signal.

They all have a built-in microphone for audio input, for use with Apple’s Siri or Google’s Assistant. Some of them have an audio input jack for an external microphone, and some have provision for an external button to activate voice commands. I never use voice input, so this was irrelevant to me.

Wired or Wireless?

I’m torn on whether to go for wired CarPlay/Android Auto or wireless. A wired interface will be immune to RF interference and will charge up my phone while in use. Wireless will be more convenient, and one less cable I have to route under trim panels in the car. I can go either way and if it proves to be a problem, I could buy a unit with the other connection method.

Winner

Criteria above culled Amazon listings down to about two dozen very similar products from brands I’ve never heard of. Not knowing how to evaluate differences, I do what most Amazon shoppers do: sort by price. I then clicked “Add to Cart” for a TTXSCAM T86 (*) which had the following features:

• 7″ IPS capacitive touchscreen with 1024×600 resolution.
• Bundled backup camera, no front facing dashcam.
• Audio-out jack in addition to built-in speaker and FM transmitter.
• Built-in microphone only. No audio-in jack or voice activation button.
• Wireless CarPlay and Android Auto

This is a very affordable unit. I thought I would start here and, if I find anything annoying, that would teach me reasons to justify going upscale. Keeping things cheap also means it’ll be less intimidating to modify as needed to fit my car. Once it arrived, I looked over everything that came in the box.

(*) Disclosure: As an Amazon Associate I earn from qualifying purchases.

I wanted to put CarPlay/Android Auto capability in my car, which is approaching twenty years old. The known solution displaces factory audio with a double-DIN bay for an aftermarket head unit. I decided against that path, because I wanted to keep the factory audio head unit (and all its electronic and stylistic integrations) intact. Instead, I want to put that capability where the factory navigation system screen sat.

Mazda’s factory navigation screen sits in a little motorized hood that retracts when not in use and keeps a screen close to a driver’s field of view while in use. I liked that position and thought perhaps I could fit an aftermarket unit within that volume. It has enough width and height to match a double-DIN bay, but only a fraction of the depth. This is not a problem because we’re not dealing with CDs or cassette tape mechanisms so modern head units can be very shallow. For example, this unit (*) claims to be a mere 1.77 inches (probably designed for 40mm) deep. Possibly small enough to fit in the stock navigation hood. Another potential candidate is to buy a unit like this one (*) that fits in a single-DIN bay and connects to an external screen. I could mount that screen in place of factory navigation screen and find some space nearby to mount the main body.

I knew these solutions are overkill, because they are full audio head units. Meaning they have their own speaker amplifiers, AM/FM tuners, and many other components that I don’t really need because I’m keeping Mazda’s stock audio head unit. I had searched for head units because I didn’t know any better, but Amazon search algorithm helped me out: it started suggesting sale listings for standalone CarPlay/Android Auto receivers. I didn’t know these things existed! But as soon as I understood they were available, I ignored the full audio head units. Standalone receivers are even shallower and, I hoped, more amenable to creative mounting schemes. Which of many offerings listed on Amazon would be a good replacement for a 2008 Mazda RX-8 navigation screen?

(*) Disclosure: As an Amazon Associate I earn from qualifying purchases.

My 2004 Mazda RX-8 was factory equipped with an optional in-car navigation system, but the map data and the electronics behind it are now twenty years out of date. Potential upgrade ideas evolved over my two decades of ownership, but I never got around to any of them. Now I’ve decided to give my car a modern (for now) capability: connect to a phone via Apple CarPlay or Google’s Android Auto.

A typical upgrade solution is to replace the factory stock audio head unit with an aftermarket unit. There’s a large selection of CarPlay/Android Auto capable products, like this randomly chosen example Pioneer DMH-W2700NEX. (*) Such replacement is relatively easy for dashboards that conform to the dual-DIN standard for audio head units. Unfortunately, interior design has been moving away from that standardized format, a trend that included my car. Stylistically integrating audio with the rest of interior now hinders my attempted upgrade.

Fortunately, the aftermarket has an answer for that as well, in the form of Metra 95-7510HG. (*) This kit replaces the entire center console panel with a new facade that accommodates a dual-DIN head end. The “HG” suffix has a glossy finish that matches the stock panel, the version without “HG” prefix may blend in better with the rest of the interior which did not have a glossy finish. There’s also a single-DIN variation with a little storage cubby, but that would be too small to accommodate a CarPlay/Android Auto touchscreen. In all cases, we lose the circle themed Mazda styling on the original panel.

The price tag on these kits is far more expensive than a plastic panel and a few brackets, because there’s a fair bit of electronics that have to be installed as well. Remember that interior integration trend? This panel, formerly hosting the audio controls, also hosts the HVAC controls. Plus, sitting above this panel is a single glowing red screen displaying both HVAC and audio status. The Metra kit includes electronics to interface with the HVAC and status display. It also interfaces with the steering wheel audio controls. And finally, a critical safety item: the emergency flasher button is also part of this assembly.

Searching on the RX-8 owner forum, I found many reports that the Metra kit is not a seamless experience. There are complaints about mechanical fit, cosmetic finish, and electrical gremlins in the electronic interface translators. They’re all solvable problems except for the last one: I don’t usually look down that far when driving. My car already has a screen up high in my normal field of view. I want to use that location. Based on the above criteria, I decided against the Metra kit and will try a different route.

(*) Disclosure: As an Amazon Associate I earn from qualifying purchases.

I am slowly grinding away at learning FreeCAD, hoping to get good enough so I can use it for future projects. There’s not much to write about learning the ropes, so I’ll write about a different project currently underway in parallel. I had recently concluded a cosmetic art car project, removing Plast-Dip I applied to make it resemble Star Wars’ BB-8. Now my car is back to its factory blue color, and I want to tackle an item that’s been on my to-do list for a long time: upgrade the in-car navigation system.

Mazda offered the 2004 RX-8 with an optional in-car navigation system. It was an expensive add-on, but I was young and flush with a tech salary, so I got mine so equipped. This luxury far predated the age of everyone having maps on their cell phones. (Reminder: the first iPhone launched in 2007.) Add-on units from Garmin and TomTom existed at the time, but the factory options were superior for several reasons:

1. Spoken directions are piped through the audio system instead of a tiny speaker on the dash.
2. A dedicated GPS antenna with a better view of the sky than a box in the cabin.
3. It has access to vehicle speed and direction to estimate position if GPS signal is lost.
4. Does not occupy a power socket and does not require a tangle of wires.
5. Screen is elegantly integrated with the interior, not a suction cup on top.

I knew map obsolescence will become a problem at some point, but I wasn’t too worried. At the time I had expected to trade the car in for another one in a few years, I didn’t expect to love the car enough to still have it today. A 2004 model year car that I bought in 2003 means the map data was probably compiled in 2002 if not earlier. This is now quite old, and I don’t recall ever hearing anything from Mazda about map updates, for free or for fee.

One advantage of having the optional factory navigation system is that, if I wanted to tackle an upgrade project, a lot of wiring is already in place as well as the factory interior trim pieces to accommodate a navigation screen. But what would this upgrade project entail? The project ideas evolved as the years went on. Early in my car ownership, I contemplated converting the in-car navigation system to an in-car Windows PC running Microsoft Streets & Trips and patched to the in-car GPS antenna. That would have been a hugely complex project, so I never got started. For a simpler alternative, I considered shucking a Garmin free of its factory enclosure and integrate it into the car, but that never happened either. Then online maps like Google Maps got good enough I thought about replacing the factory navigation screen with an Android tablet with Google Maps running offline maps downloaded at home via WiFi. While I procrastinated, data plans got cheap enough for our phones to use live data online. So, I thought about putting a phone mount inside the factory navigation hood.

None of those happened, but I’m finally tackling the project now. The current state of the art for in-car integration takes the form of Apple CarPlay and Android Auto. That’ll be my target but I’m taking an unconventional route.