Phone Link and Companion

Phone link and Companion

Dashwheel Companion (dashwheel-companion.apk in every release) runs on the driver's phone. The phone shares its connection with the head unit through its hotspot; the two talk over Wi-Fi.

Pairing

Settings → Connections → Pair a phone shows a QR code. Scan it in the companion and confirm. The link is end-to-end encrypted (shared secret, ECDH P-256, AES-256-GCM). Either side can revoke it.

Start in the car: the companion can start sharing by itself when the phone connects to the car's Bluetooth.

What it does

Feature
Notifications and messages	Shown in the Notifications widget; read aloud; quick or voice replies; mark read / clear on the phone
Calls	Phone calls and app calls (WhatsApp, Signal, Telegram…): caller card with Answer / Decline, then Hang up, over any app. Sound stays on the unit's Bluetooth hands-free, so pair the phone with the unit too
Phone favourites, agenda, destination	Favourites for quick dial, the phone's agenda, send a place to the car's navigation
Where's my car	Every stop and the saved parking spot go to the phone: Map and Walk there
Parking timer	Set on the car's Parking timer tile; the phone reminds you 10 minutes before the end and when it runs out
Share my arrival	The car texts a favourite contact your arrival time, through the phone
Drive log	Each drive with distance, time, speeds and eco score; the last 100 on the phone (Drives tab)
Type from the phone	The phone types into the selected text field on the head unit (or Send to car from any app's share / text menu)
Registration scan	Car tab: scan the car's registration document; the plate, VIN, first registration and the next roadworthiness test go to the car, the photo stays on the phone. See Car Care and Servicing
Car picture	Build My Car Picture from photos and send it (photos are turned upright and resized, so camera pictures and HEIC go through)
Phone's GPS for the car	The phone finds its position in seconds where the unit takes minutes: while linked, its position stands in for the unit's, in Maps, Waze and every tile. Companion: Setup step Position for the car (location allowed all the time). Car: Settings → Connections → Use the phone's GPS, on by default, with the phone's satellites in use. The unit's own GPS takes back over 4 s after the phone stops sending, or when its fix is too wide. Needs root or the unit's ADB on the car side. Status: not yet tried on devices
OBD through the phone	OBD through this phone → Choose the adapter: the phone holds the Bluetooth OBD adapter and passes it on, so calls and Android Auto on the unit's Bluetooth no longer get in the way. The car waits 15 s for the phone and lets go at once when the link drops; a phone that stops reading is noticed within seconds and dialled again. See Car Data (OBD and CANbox)
Unit log	Settings → System → Lab → Unit log on the car sends its log to the phone, to share as a bug report
Second screen pairing	Pair a car scans the Raspberry Pi's code: Second Screen Setup and Pairing
Updates	GitHub edition: updates itself from GitHub (Setup tab). The Play edition (com.dashwheel.companion) updates through Google Play

Companion tabs: Home, Drives, Car, Setup.

On Android 13+, a sideloaded app's Notification access is a restricted setting: App info → ⋮ → Allow restricted settings first. The companion shows this step.

Android 15+ phones (Galaxy S25 and others): companions before 2026-10-04 refused the car on their own hotspot; update the companion. The companion only answers the car on its own hotspot, never on another Wi-Fi or mobile data.

Status: link, notifications and calls car-tested; where's my car, typing and the companion updater not yet confirmed in the car.