ITOHI — Open-Source Hardware, Embedded Systems & DIY Builds
RadioMaster GX12: Why I Chose It Over the Boxer
Aug 16, 2026 · 6 min read · fpv edgetx radiomaster-gx12 elrs crsf telemetry radio customisable-function-switches ·
My third radio, and the first one I chose for a reason that never appears in a review: it fits in the top box of a GS Adventure alongside two drones, goggles and batteries. What the six customisable function switches actually enable, and where the GX12 loses to a Boxer.
Read MoreEdgeTX Telemetry Rebuilt in Flight Order (Part 9)
Aug 16, 2026 · 9 min read · fpv edgetx logical-switches prearm telemetry minimum-voltage gps-rescue refactor ·A clean-sheet layout: validity helpers at L1 to L4, then recording, battery and GPS in the order I use them. Plus a minimum-voltage readout that speaks punch-out sag while I am still flying.
Read MoreEdgeTX Debounce and False Battery Alarms (Part 8)
Aug 16, 2026 · 7 min read · fpv edgetx logical-switches debounce voltage-sag link-quality blackbox troubleshooting ·Stacked thresholds that layer sirens, zero debounce against punch-out sag, an alarm that fires before the first telemetry frame arrives, and the link-quality warning I never wired up.
Read MoreELRS Gemini and True Diversity Antennas (Part 7)
Aug 16, 2026 · 7 min read · fpv elrs antenna-diversity polarisation radiomaster-gx12 gemini crsf telemetry ·ELRS control-link antennas are linearly polarised, not circular like video. Why one horizontal and one vertical on a true diversity receiver beats a single antenna, and why my telemetry already measures it.
Read MoreELRS Telemetry Ratio and EdgeTX Log Rate (Part 6)
Aug 16, 2026 · 9 min read · fpv edgetx crsf elrs telemetry-ratio logging rxmap antenna-diversity data-analysis ·
ELRS telemetry ratio, CRSF frame round-robin and the EdgeTX log period sit in series. Why the arithmetic is not the answer, how to get the real per-sensor rate out of your own CSV, and the 3D viewer I built to read it.
Read MoreThe callouts come from the stock EdgeTX voice pack, not from anything I recorded. What to scrub from a model YAML before publishing it, and the positional sensor-index trap that makes a shared config misbehave silently.
Read MoreEdgeTX Battery and GPS Voice Callouts (Part 4)
Aug 16, 2026 · 7 min read · fpv edgetx special-functions gps-rescue betaflight telemetry altitude easa ·
The battery ladder, the satellite callouts, and an altitude alarm that fires on change rather than absolute height. Including the self-test I like most and the delta function I did not plan.
Read MoreEdgeTX Logical and Function Switches (Part 3)
Aug 16, 2026 · 6 min read · fpv edgetx radiomaster-gx12 logical-switches customisable-function-switches crsf telemetry ·
How EdgeTX customisable function switches, an RGB colour per subsystem, and one AND slot per logical switch turn eleven threshold detectors into three things you can switch on and off.
Read MoreBetaflight Battery Voltage Calibration (Part 2)
A miscalibrated voltage reading does not look broken, it looks plausible. Why report_cell_voltage makes a vbat_scale error propagate twice, and what the 3S-to-4S move does to your alarms.
Read MoreWhy EdgeTX Voice Telemetry Beats the OSD (Part 1)
Aug 16, 2026 · 5 min read · fpv edgetx radiomaster-gx12 elrs crsf telemetry betaflight report-cell-voltage lihv ·
A low-battery number in the corner of the OSD is an interface failure, not a pilot failure. Why I made my RadioMaster GX12 speak, and the one flight-controller setting the whole thing depends on.
Read MoreBetaFPV Meteor75 Pro II: Fighting Resonances
Aug 13, 2026 · 62 min read · betaflight blackbox vibration resonance meteor75 whoop gyroflow measurement ·
Craft name Snake. It started life as a Meteor75 Pro, and it is now a Meteor75 Pro II — frame and canopy ordered off AliExpress, everything expensive carried straight over. Same Matrix 1S 3-in-1 FC. Same narrow-FOV DJI O4 air unit. New shell, old guts, and by the time I was done, 169 flights and 15,574 seconds of logs …
Read MoreUV Fluorescence Experiments With a DIY Spectrometer

With the spectrometer alignment sorted and PySpectrometer3 taking shape, the obvious next experiment was UV fluorescence. Minerals, biological samples, gemstones — a lot of interesting chemistry shows up as emission spectra under UV excitation that you'd never see under white light. The setup is conceptually simple: …
Read MoreDIY Diffraction Grating Spectrometer, Not a Prism

Still trying to solve the monitor calibration problem — need to measure the actual spectral output of my monitor's primaries, not just RGB. The CR30 held against the screen gives something, but it's not designed for emissive sources. What I need is the pocket jewel spectroscope I've been using all along, properly …
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