How We Built a Muse Gadget for the Car

An engineering case study on building a conversational AI vehicle companion. By Jimmy Chung, hardware engineer at Skytech.

This is the engineering case study behind our Muse Gadget Car Audio Edition. We had a working prototype in our lab within three months of starting, because the desktop Muse Gadget reference design solved 80% of the problem. The remaining 20% — automotive-grade power, LTE, GNSS, in-car acoustics — is what this article covers.

The starting point: Module 1 desktop reference

The Muse Gadget's Module 1 is a Wi-Fi companion with a friendly AI mascot. It has a custom Muse SoC, Wi-Fi 6, BLE, a 5-inch color display, USB-C power, and the mascot engine v1 running on Meta's Muse platform.

For a car, we need to add four things on top of that:

1. LTE — because Wi-Fi isn't available on the road
2. GNSS — for vehicle location, sentry mode, and "where is my car" voice queries
3. Automotive-grade 12V power — because USB-C isn't a thing in cars and the temperature range is wider
4. BLE / CAN bus pairing — to read TPMS sensors, OBD2 adapters, and remote-start hardware

Everything else — the Muse voice pipeline, the mascot engine, the display, the Wi-Fi 6 hotspot for passengers — stays the same. That's why we got to a working prototype so quickly.

Hardware additions for the car edition

1. LTE modem

We added a 4G LTE Cat-1 modem on a separate module. Cat-1 (not Cat-M or NB-IoT) because we need real-time voice streaming over LTE for the Muse conversational agent. The modem sits on a PCIe M.2 connector so it can be swapped for a 5G module in the future.

The modem shares the Wi-Fi antenna path through a diplexer, so we don't need a third antenna cut. Cost: ~$12 per unit at 10K MOQ.

2. GNSS receiver

A u-blox NEO-M8N module. We picked it over cheaper Chinese GNSS chips because the cold-start time and the multi-constellation (GPS + Galileo + GLONASS + BeiDou) make a difference in urban canyons. The module sits on a shared antenna path with the LTE modem via another diplexer.

3. Automotive-grade 12V power supply

This is the most underrated part of an automotive hardware design. Cars generate load-dump transients up to +40V when the alternator is disconnected, voltage drops to +6V during cranking, and the cabin temperature range is -40°C to +85°C.

We replaced the USB-C input with a wide-input 12V→5V buck regulator (TI LM53603) plus a TVS diode for load-dump protection. The result is a power supply that survives the cranking drop, the load-dump spike, and the cold-soak at -30°C. Cost: ~$3 per unit at 10K MOQ.

4. BLE / CAN bus interface

The Muse SoC already has BLE 5.0. We added a separate CAN bus controller (TL9010 from Texas Instruments) on SPI for OBD2 access. The CAN bus controller handles the bus arbitration and error detection, freeing the Muse SoC to focus on voice and UI.

For TPMS sensors and remote-start modules, BLE pairing is sufficient — most aftermarket hardware uses BLE 4.0+ for setup and configuration, even if the actual data goes over a different protocol.

Voice pipeline tuning for in-car acoustics

The Muse platform's local-first voice pipeline works offline. This is critical for in-car use, because drivers lose cellular coverage in tunnels, parking garages, and remote areas. A voice assistant that stops working every time the signal drops is a voice assistant that drivers stop using.

The Muse voice pipeline needs three acoustic adjustments for in-car use:

1. Beam-forming microphone array. A single MEMS mic picks up too much road noise. We use a 3-mic beam-forming array pointed at the driver's head position.
2. Road noise profile. We trained the noise canceller on road noise at 50 km/h, 80 km/h, and 120 km/h. The canceller profiles are different for each cabin type.
3. Cabin reverb. Cars are small enclosed spaces with hard surfaces. We tuned the wake-word detection to ignore short reflections.

The result: "warm up my car" works reliably at highway speed with the windows closed, with the radio on, and with a passenger talking.

What it actually does in a car

Once installed, the Muse-in-car gadget does these things out of the box:

• "Warm up my car" — sends a remote-start command via BLE to the aftermarket remote-start module, with a 10-minute timeout for safety.
• "Check my tires" — polls the paired TPMS sensors, reports current pressure and temperature, flags any tire below threshold.
• "What's wrong with my car?" — reads the OBD2 fault codes via CAN bus, translates the codes to plain English ("Mass airflow sensor low input — usually means a dirty sensor or a wiring issue").
• "Where is my car?" — reports the GNSS location, with a privacy toggle so location is only shared with paired devices.
• Sentry mode — when parked, the gadget monitors the cabin camera for motion and uploads 30-second clips via LTE if motion is detected.
• Passenger hotspot — Wi-Fi 6 access point for passengers' phones and tablets, using the LTE uplink.

Compatibility with the aftermarket channel

Skytech is a long-standing OEM manufacturer for AAMP Global / Stinger Solutions. The PAC and Stinger lines include aftermarket head units, TPMS sensors, and remote-start modules. The Muse-in-car gadget is designed to pair cleanly with all of these.

The 12V dealer and installer network at PAC and Stinger — roughly 800 dealers across North America — is the natural channel for this product. Installers already know how to wire up a TPMS sensor or a remote-start module. Adding a Muse gadget to the install is a 30-minute job.

What's not done yet

Three things we're still working on:

1. OTA sensor profile learning. Right now, each TPMS sensor model needs a manual pairing step. We want the device to recognize new sensor models automatically and add them to its profile.
2. Multi-vehicle support. Most car audio distributors want a device that follows the customer, not the car. We're working on a "pair once, install anywhere" mode where the gadget learns each new car it's installed in.
3. Subscription model. The conversational voice service runs through a managed subscription layer. We're working out the billing relationship and revenue split with AAMP / Stinger for the dealer channel.

If you have a similar idea

If you're exploring the same idea — a conversational AI vehicle companion, an aftermarket car audio gateway, or a TPMS / OBD2 / remote-start voice interface — Skytech is probably already building it. We have:

• A working prototype, not a concept
• Apple MFi License #120974 since 2011
• Manufacturing in Thailand (4 Yamaha SMT lines, MES + 5S + SPC lean production) and Dongguan/China
• A distribution channel through AAMP / Stinger / PAC's 12V dealer and installer network
• A reference design (the desktop Muse Gadget Module 1) that's already shipping

If you have a similar idea, reach out before building your own:

About me

I'm Jimmy Chung. I founded Skytech Creations Limited in 2011 with Apple MFi License #120974. Engineering in China, factories in Thailand and Dongguan/China. I've designed every product in the SKYTAG line and the Muse Gadget reference design. I write honestly about what we build, including the parts that don't work.

Got an engineering question I should answer in a future post? Email me.

FAQ — Muse Gadget in car