Flying TeleMini with AltosUI on iPhone

TeleMini is the small, light member of the Altus Metrum flight-computer lineup — dual deploy in an airframe that can’t spare the size or mass of a TeleMetrum or TeleMega. That smaller footprint comes with honest tradeoffs on what the app can show you, and this guide walks through exactly what you see on your iPhone when TeleMini is doing the flying.

What TeleMini reports (and what it doesn’t)

TeleMini (v2 and v3) reports a barometer and two pyro channels. No GPS. No IMU. That is the whole hardware story, and it shapes everything you see in the app. You get altitude, vertical velocity derived from the barometer, baro-driven state transitions through the AltOS state machine, and continuity status for the two pyro channels — drogue and main. You do not get a GPS position, a ground track, tilt during boost, or any of the features that depend on those.

This is by design. TeleMini exists for small airframes where flight-computer weight matters, or for second boards on clustered flights where the primary has the GPS. If you want full telemetry, the answer is TeleMetrum or TeleMega. If you want the smallest Altus Metrum deploy computer, the answer is TeleMini. For the canonical hardware reference, see altusmetrum.org/TeleMini.

On the Pad

The Pad tab still gives you a readiness view with TeleMini flying: whether the flight computer is armed, whether the two pyro channels show continuity, the flight-computer battery voltage, firmware version, the receiver’s battery voltage, and the receiver’s own location. What you do not see is a GPS-lock indicator for the rocket, because there is no GPS on the rocket — the absence there is expected, not a fault.

Live on the Flight tab

Once the rocket leaves the rail, the Flight tab shows the current state, current and maximum height, and current and maximum speed, with voice callouts on state transitions and peak values. Direction-aware speed callouts still work: “ascending at N m/s” during boost and coast, “descending at N m/s” during descent. The voice-callouts guide has the detail.

What you will not see on the Flight tab with TeleMini is tilt during boost (no IMU) or the range, bearing, and elevation to the rocket (no GPS on the rocket end to compute those from). Be honest with yourself about that before you pick this flight computer — if you want to watch tilt climb during the burn, you want TeleMega.

Map and Recover tabs, TeleMini edition

Without a rocket-side GPS, the Map and Recover tabs lose their GPS-driven features. The Map tab will still show your position and the launch field, but there is no rocket track to plot because there is no GPS position to plot. The Recover tab’s List view cannot report a bearing or a distance to the rocket, because it has no coordinates to do the math against.

The Recovery Map walking mode and the AR Recovery HUD both depend on a GPS-equipped flight computer, so neither is useful with TeleMini. That is a consequence of the hardware, not a limitation of the app. Recovery with TeleMini is old-school: listen for the beacon, watch the rocket come down, walk to it.

IDLE mode and pre-flight igniter testing

IDLE mode is a prep-area tool, not pad-side work. TeleMini supports the same pre-flight pattern as the rest of the Altus Metrum lineup on iOS: at the prep table, with the receiver within radio range of the TeleMini, you can put the receiver into IDLE mode to query device state, set the callsign, read configuration, and run a continuity-protected igniter test with countdown guards. For TeleMini that means verifying drogue and main continuity before the rocket ever leaves your prep area. Once you carry the airframe to the pad and power it up vertical, the flight computer wakes in Pad mode and is transmitting telemetry — IDLE work has already happened by then.

Replay and post-flight review

Flight Replay works with every supported flight computer, TeleMini included. Play the recorded .telem file back through the full telemetry pipeline in Actual timing (original packet intervals) or Fast timing (one-second intervals for a quick scan). On TeleMini flights the Flight tab replay is the main event because the Map and Recover tabs have no GPS position to drive them. Use replay to review boost-to-apogee timing, main-deploy altitude, and the baro-driven state transitions.

When TeleMini is the right answer

TeleMini shines in three situations. Small airframes where a TeleMetrum or TeleMega won’t physically fit. Low-altitude flights where GPS fix time is not the issue and the barometer does the whole job. Clustered or multi-stage builds where another GPS-equipped flight computer is doing the tracking and you just need the small board to handle pyro. If your flight profile fits one of those, the Pad and Flight views on your iPhone cover what you need.

Back at the car

AltosUI still writes a .telem file for the TeleMini flight, and you can still open it with Quick Look in the Files app and generate an on-device Flight Report. The report fills in the sections it can from barometric data — altitude profile, phase timeline, recovery performance, aerodynamic deceleration — and labels unavailable GPS-dependent fields rather than showing unexplained dashes. See the telem-files guide and the Flight Report PDF guide for the export path.

For the bigger picture, the launch-day checklist is the full end-to-end walk, and AltosUI on iPhone: what it is (and what it isn’t) places the iOS app next to the desktop workbench.

One reminder on licensing

To legally operate an Altus Metrum flight computer in the US, you need at least a Technician-class amateur radio license. The canonical page is altusmetrum.org/Radio, and the ARRL licensing page is the best place to start if you don’t already hold one.