Indicator and Caution Lights¶

What you'll do: configure physical cockpit indicator lamps and the caution panel so they light up from DCS and BMS sim state.

There are two distinct output types covered here:

Indicator lights: individual lamps (gear lights, FLCS PWR, master caution, etc.) each driven by one GPIO pin.
Caution panel: the full 32-lamp caution/advisory panel, driven by a TLC59281 shift-register chain over SPI on an AIM board, or by one MAX7219 on an Arduino, Teensy or Pico.

Note

On AIM boards, physical indicator and caution output requires firmware v2.2.0 or newer. Check your board's firmware version on the Firmware page before wiring. Open Hardware boards drive indicator lamps from any pin (see the wiring table on Open Hardware). On an Arduino, Teensy or Pico, the caution panel runs from one MAX7219, and any other lamp can sit on a MAX7219 lamp matrix instead of a pin of its own. See Lamps on a MAX7219.

Indicator lights¶

How they work¶

Each individual lamp connects to one GPIO pin on the board. The manager drives the pin high or low based on the sim state for that light. Gear down-and-locked, master caution, FLCS fault, etc. The board's GPIO expander handles the output; no external driver chip is needed for standard indicator lamps.

Setting them up¶

Indicator lamps are part of the panel they belong to. You don't add them separately. When you select a panel in Step 2 of the board wizard (for example, the gear panel or the eyebrow lights panel), the wizard automatically includes every lamp that panel contains.

In Step 3: Pin Assignments, each lamp appears as its own row. Assign each one to an available GPIO pin, the same way you assign switches. Each lamp needs its own pin.

Tip

Use GPIO pins on the opposite side of the MCP23017 expander from your switch inputs if possible. Keeping outputs grouped separately from inputs makes troubleshooting easier later.

Lamps and buttons inside a cluster¶

On the F-16C, the indexers, the eyebrows, MASTER CAUTION, the ECM buttons and the threat warning buttons are clusters: several lamps, and in some of them buttons, drawn as one part on Console Panels. Each lamp and each button gets a pin of its own, on every board. In the Pins step the cluster's lamps share one row with a pin slot per lamp, and each button has a row of its own.

Panel	Lamp row: its lamps	Button rows
AOA INDEXER	AOA INDEXER: SLOW, ON SPEED, FAST
RIGHT INDEXER	AAR: RDY, AR/NWS, DISC
EYEBROW LIGHTS	L EYEBROW: TF FAIL
EYEBROW LIGHTS	R EYEBROW: ENG FIRE, ENGINE, HYD/OIL PRESS, FLCS, DBU ON, TO/LDG CONFIG, CANOPY, OXY LOW
MASTER CAUTION	MASTER CAUTION	MASTER CAUTION
ECM	1 to 6, FRM and SPL: S, A, F and T on each	1 to 6, FRM, SPL
THREAT WARNING AUX	THREAT WARNING AUX: SEARCH, ACTIVE, ACT POWER, ALT LOW, ALT, SYSTEM POWER	SEARCH, ACT/PWR, ALTITUDE, POWER
THREAT WARNING PRIME	TWS PRIME: HANDOFF UP, HANDOFF H, MISSILE LAUNCH, MODE PRI, MODE OPEN, UNKNOWN U, UNKNOWN, SYS TEST ON, SYS TEST, TGT SEP UP, TGT SEP DOWN	HANDOFF, MISSILE LAUNCH, MODE, UNKNOWN, SYS TEST, TGT SEP
LANDING GEAR	LG HANDLE LAMP, the light in the gear handle

Wire the buttons as pushbuttons. In DCS, the ECM buttons and the TWA POWER button stay in or out, so a pushbutton on one of them turns it on or off with each press.

An LED for O2 FLOW¶

The oxygen FLOW indicator can be a single LED that lights whenever the indicator in the sim shows white. On Instruments, find O2 FLOW under OXYGEN and pick LED. (On Console Panels, the same choice is LED in the ⋯ menu on its row.) In the Pins step it is then a lamp row with one pin, and Test lamp in its ⋯ menu on Console Panels lights it.

Wiring¶

Connect the lamp's anode (positive leg) to the GPIO pin header, and cathode (negative leg) to GND. The GPIO pin drives high (3.3V) when the lamp should be on.

If you're using higher-current lamps, add a current-limiting resistor in series. Most standard indicator LEDs run well at 3.3V with a 100-330 Ω resistor. Check the LED's datasheet for its forward voltage and rated current.

Caution panel¶

How it works¶

The caution panel's 32 lamps are driven by a TLC59281 constant-current LED shift register over SPI. All 32 lamps share one SPI channel. You assign the channel once and the firmware handles the rest. There is no pin-by-pin assignment for caution lamps.

The manager maps each DCS caution light argument (or BMS caution flag) to its corresponding TLC59281 output channel automatically, based on the panel catalog's hardcoded layout. You don't need to configure individual channels.

In the manager, the caution panel has its own card on Instruments, not on Console Panels. The card shows where its lamps are wired and every cell lit as the sim lights it.

Setting it up¶

Step 2: Panels: Check Caution Panel in the panel list. A slot dropdown appears. Select which SPI channel on your board the TLC59281 chain is wired to (SPI Channel 1 or SPI Channel 2).

That's it. No Step 3 assignments are needed for caution lamp outputs. The 32-channel mapping is handled by the catalog.

Wiring¶

Connect the TLC59281 chain's SPI input (SDI, CLK, LE, /OE) to the SPI channel header on your Sidewinder board. The TLC59281 is a daisy-chainable shift register. If you have two ICs for a full 32-lamp panel, chain the SDO of the first to the SDI of the second.

Power the TLC59281 at 3.3V or 5V depending on your lamp supply. The ESP32's SPI lines are 3.3V and are compatible with 3.3V-powered TLC59281 directly. If you run it at 5V, add a level shifter on the SPI lines.

The /BLANK (output enable) pin should be pulled low to enable outputs. If you leave it floating or pull it high, all lamps stay off regardless of the data sent.

Note

If the caution lamps light in the wrong positions, the daisy-chain bit order may be reversed from what the catalog expects. Swap the first and last TLC59281 in the chain, or swap the two ICs' positions, to reverse the order.

On an Open Hardware board¶

On an Arduino, Teensy or Pico, the 32 lamps run from one MAX7219 on three pins, two LEDs a lamp. Check Caution Panel in Step 2, then give its LAMPS row in Step 3 its DIN, CLK and LOAD pins. The exported pinout lists the digit line and the two segment lines for every lamp. See Lamps on a MAX7219.

Check it worked¶

In Avionics → Console Panels, find a lamp, click its ⋯ button and choose Test lamp. Every cell of that indicator lights for three seconds, no sim needed. Then load into a mission in DCS and trigger the relevant cockpit state (put the gear down, activate master caution, etc.). The corresponding lamp on your panel should light.

For the caution panel, open Avionics, then Instruments, and click Test lamps on the CAUTION PANEL card: every lamp lights for three seconds. Then trigger a caution condition in DCS (engine fault, fuel low, etc.) and verify the correct lamp lights. The card lights the same cell at the same time.

If something's wrong¶

Problem	Fix
Indicator lamp never lights	Check the GPIO pin assignment in Step 3. Confirm the pin is not also assigned to a switch input. Verify the lamp is wired anode → GPIO, cathode → GND.
Indicator lamp is always on	The GPIO may be floating high. Check the pin assignment and confirm the firmware version is 2.2.0+.
Caution panel lamps light in wrong positions	On an AIM board, the TLC59281 daisy-chain bit order is reversed: swap the order of the ICs in the chain. On a MAX7219, check each LED against the exported pinout: anode to its segment line, cathode to its digit line.
Caution panel does nothing	Check that the SPI channel in Step 2 matches the physical wiring. Confirm /BLANK is pulled low.
Firmware page shows version older than 2.2.0	Update board firmware before testing outputs. See Update Board Firmware.