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go-lepton

Streams images taken on a FLIR Lepton connected to a Raspberry Pi SPI port to over via WebSockets via embedded HTTP server. It sends the raw data which is then processed as javascript.

<a href="https://www.raspberrypi.org/"><img src="https://maruel.net/images/raspberrypirev2.jpg" width=107 height=71 /></a> + <a href="https://twitter.com/groupgetscom/status/524762927895953409"><img src="https://maruel.net/images/flir.jpg" width=102 height=76 /></a> → <a href="https://github.com/maruel/go-lepton"><img src="https://maruel.net/images/photo_ir.png" /></a>

Prerequisite Setup

Setup is fairly involved so it's in its dedicated SETUP.md page.

Installing

Building go-lepton on the Raspberry Pi v1 takes ~10s which is slow but still much faster than cross-compiling and transferring the file in.

go get github.com/maruel/go-lepton/cmd/lepton

Then run lepton.

Verification

Running the following command should have the corresponding output:

$ lepton -query
Status.CameraStatus: SystemReady
Status.CommandCount: 0
Serial:              0x12345
Uptime:              48m56.275s
Temperature:         30.75°C
Temperature housing: 26.34°C
Telemetry:           Enabled
TelemetryLocation:   Header
FCCMode.FFCShutterMode:          FFCShutterModeExternal
FCCMode.ShutterTempLockoutState: ShutterTempLockoutStateInactive
FCCMode.VideoFreezeDuringFFC:    Enabled
FCCMode.FFCDesired:              Enabled
FCCMode.ElapsedTimeSinceLastFFC: 48m56.285s
FCCMode.DesiredFFCPeriod:        5m0s
FCCMode.ExplicitCommandToOpen:   Disabled
FCCMode.DesiredFFCTempDelta:     3.00°K
FCCMode.ImminentDelay:           52

Performance

Reading the SPI port takes ~50% the CPU of a Raspberry Pi v1 running Raspbian. There's a rumor about DMA based transfer but for now that's the fastest that can be achieved.

Power

The FLIR Lepton takes ~150mW. The breakout board doesn't expose the necessary pins to put it in sleep mode. Sadly this means that if the Lepton goes into a bad mode, rebooting the Pi won't help.

Debug build

To debug cmd/lepton/static/root.html so that each HTTP request returns the file from disk, use:

go install -tags debug ./cmd/lepton