Project Files of Air-Core Gauge Library for Proteus V1.0 (Arduino + L9110S)

AIR-CORE GAUGE LIBRARY FOR PROTEUS - V1.0 (the air-core movement of car gauges
behind a 52 mm tachometer dial)
Designed by The Engineering Projects
www.TheEngineeringProjects.com

IMPORTANT LINKS
Article (read it first - pictures, step by step, every feature explained):
  https://www.theengineeringprojects.com/2026/11/air-core-gauge-library-for-proteus-v1-0.html
Report a bug or suggest a feature (our forum):
  https://www.theengineeringprojects.com/forum/category/motor-driver-proteus-library
The demo runs on our Arduino UNO V4.0 (included) - working LEDs, RESET and a
built-in serial monitor - its own article:
  https://www.theengineeringprojects.com/2026/10/arduino-uno-library-for-proteus-v40.html
The demo's driver is our L9110S Motor Driver - a SEPARATE library, not in this
package: download and install it first - its own article:
  https://www.theengineeringprojects.com/2026/10/l9110s-motor-driver-library-for-proteus-v1-0.html
Support us (the libraries are free):
  https://www.theengineeringprojects.com/donate

FILE STRUCTURE
Air-Core-Gauge-TEP-v1.0/
|-- Proteus Library Files/
|   |-- ArduinoV4TEP.LIB                              201.9 KB   TEP Arduino boards V4.0 (UNO) -> LIBRARY
|   |-- TEPAIRCORE.LIB                                 32.6 KB   the library -> LIBRARY folder
|-- Proteus Model Files/
|   |-- TEPAIRCORE.DLL                                308.5 KB   the model -> MODELS folder
|   |-- TEPARDUINO.DLL                                883.5 KB   the Arduino board model -> MODELS folder
|-- Proteus Simulation/
|   |-- AirCore_Gauge_Demo.hex                         24.9 KB   the demo firmware
|   |-- Air-Core-Gauge-L9110S-ArduinoUnoV4.pdsprj      25.6 KB   the demo project
|   |-- TEPAIRCORE.DLL                                308.5 KB   copy of the model
|   |-- TEPARDUINO.DLL                                883.5 KB   copy of the board model
|-- Arduino Code/
|   |-- AirCore_Gauge_Demo/AirCore_Gauge_Demo.ino       6.2 KB   the demo sketch (source of the .hex)
|-- README.txt                                        ~18.5 KB   this file
Total: 2.63 MB (unzipped). The C++ source code of the models is not included.

WHAT IS IT?
A simulation model of the air-core gauge movement - the movement behind the
tachometers, speedometers, fuel and temperature gauges of countless car
dashboards, and a favourite of makers who build their own clusters and sim
racing dashboards. It has no gears and no spring: two coils wound crossed at
90 deg on a plastic bobbin and, inside them, a disc magnet on the needle's
shaft. The magnet turns to the direction of the two coils' field, so the
needle points at atan2(SIN, COS) - anywhere round the full circle. Our own
model:
  * The two coils - COS between COS+ / COS-, SIN between SIN+ / SIN- - are in
    the circuit with their resistance and inductance: 230 ohm and 25 mH each,
    12 V coils (52 mA). An H-bridge drives them (L9110S, L293D, L298N).
  * The needle follows the field: the COS coil along the needle's 0, the SIN
    coil along 90 deg. Drive COS with cos(angle) and SIN with sin(angle) and
    the needle goes to that angle.
  * A silicone fluid damps the magnet: a move settles in about half a second
    with a small overshoot. A pivot friction and a small return magnet bend
    the reading by up to about 1.6 deg (50 r/min) at the full field.
  * The return magnet sits at the stop pin: with the coils off the needle
    sinks slowly back to 0 (from past 174 deg it falls onto the pin's far
    side). Property RETURN NO: no return magnet - the needle stays put.
  * The stop pin just below the 0 mark: the needle cannot pass it from either
    side (-6 to 354 deg). A field that jumps more than 180 deg sends the
    magnet the short way round - onto the pin, where it stays: STUCK AT THE
    PIN. Move the field in steps.
  * A weak field (under 25 % of the rated current) holds the needle loosely:
    the return magnet and the pivot pull it off - WEAK FIELD.
  * Warnings: more current than a 12 V coil takes, one coil without current
    (a wire off).
  * A finger on the needle (a click on the dial) and a tap on the gauge (the
    pop-up's chip) - the fluid settles it back.
The symbol shows a 52 mm car tachometer from the front: the chrome bezel, the
black face with its 0 - 8 x1000 r/min scale over 270 deg and the red zone, the
red needle and its hub, and on the left the movement's terminal block with its
four brass terminals and the coil wires. At Run the needle turns to the
simulated angle, the scale follows properties RANGE and REDLINE, and an orange
mark on the rim shows where the field points. The plate, the coil LEDs COS and
SIN (green: the current flows + to -, red: - to +), the rating line and the
strip under the plate (VALUE, ANGLE, FIELD, OPEN PANEL) are TEP additions; the
real gauge has none of them.

ONE DEVICE (search "air-core" or "gauge" in Pick Devices):
  AIRCORETEP     "Air-Core Gauge V1.0"   (category Electromechanical >
                 Motors), model TEPAIRCORE.DLL
  The pop-up panel "TEP Air-Core Gauge" opens at Run (and with OPEN PANEL on
  the strip) - the look of the TEP Serial Monitor. Tabs Gauge, Graphs, Event
  log and Check; gear and ? icons for Settings and Help; the palette icon
  switches the theme:
    Gauge      the state in big letters (SHOWING 3162 R/MIN, MOVING, WEAK
               FIELD, AT THE PIN, STUCK AT THE PIN, OFF); the dial with the
               needle and the field; the live values (the reading, the needle,
               where the field points, how far off, the field's size, the
               state, the two coil currents); the field vector, drawn the
               dial's way round; the coil currents over the last second. The
               toolbar: Hold it (a finger on the needle), Tap the gauge.
    Graphs     the needle and the field, the two coil currents and the
               field's size over the last 5, 15 or 30 s. Live / Freeze.
    Event log  FIELD ON / OFF, every move ("STEADY at 6839 r/min (230.8 deg)
               - from 3180 r/min in 0.66 s, 1.5 deg off the field"), STUCK AT
               THE PIN, WEAK FIELD, the warnings; filters All / Moves /
               Warnings, Pause, Clear
    Check      Good for: a needle that does not move, points the wrong way,
               reads low, sticks at the pin or swings past and back - the
               coils, the current, the field, the accuracy, the moves, the
               pin, the return magnet, with tips
    Settings   theme, text size, open at Run, window size
    Help       report a bug, suggest a feature, article, updates, donate,
               forum; Copy diagnostics for a bug report

TEST STATUS
V1.0: verified in Proteus 8.5 on 29 Oct 2026 (the demo project as shipped: an
A3 sheet, an Arduino UNO V4.0 with its built-in monitor, our L9110S driver -
its pop-up version, from its own library - on +12V, RV1 and the gauge; all
pop-ups open). What the runs showed:
  * The project loads and starts cleanly; the sketch's self-test sweeps the
    needle to 8000 r/min and back, then RV1 (40 %) sets it: "STEADY at 3162
    r/min (106.7 deg)", COS -17 mA, SIN 49 mA, the field at 100 %.
  * "rpm 6800": "STEADY at 6839 r/min (230.8 deg) - from 3181 r/min in 0.66 s,
    1.5 deg off the field" - in the red zone.
  * "rpm 900", then "jump 7000" - the field jumps 206 deg at once: "STUCK AT
    THE PIN - the field jumped to 236 deg the short way round: move it in
    steps under 180 deg". "rpm 3000" slews the field back past the far side
    and the needle frees itself: "STEADY at 2948 r/min (99.5 deg)".
  * "weak 15": "WEAK FIELD - 15 % of the rated current: the needle sits 6.5
    deg off the field" - and it sinks further, to 12.5 deg off.
  * "angle 300": past the scale, "STEADY at 8928 r/min (301.3 deg)".
  * The Tap chip: the needle jumps and settles back in 0.28 s.
  * "off": the return magnet takes the needle down, from 133.9 deg to 20.4 deg
    in 7 s; "on", "sweep", "rev" (900, a blip to 6800, back to 900).
  * The L9110S's own pop-up at 900 r/min (30 deg): motor B (the COS coil)
    FORWARD 86 % at 490 Hz, motor A (the SIN coil) FORWARD 51 % at 977 Hz -
    cos 0.87 and sin 0.50; its scope draws the two coil voltages as a cosine
    and a sine through the sweep and the blip.
  Plus automatic checks on a PC, 0 failed: 39 on the movement (the COS coil
  alone: 52.2 mA, the needle at 0; 3500 r/min within 2 deg, settled in 0.5 s;
  a step to 170 deg overshoots to 175 and settles; a jump 0 to 270 deg sticks
  at the pin, the same move in steps gets there; 357 deg and 340 deg end on
  the pin; off: back to 0, from 300 deg onto the pin's far side, without the
  return magnet it stays; 15 % = WEAK FIELD; a PWM on both coils = the
  average; a SIN coil without current is found; 20 V = over-current; a finger
  holds the needle, a tap settles back; every event text fits); 2 on the
  pop-up pages rendered; the demo project read back from disk (75 checks:
  devices, pins, wires, labels, no wire through a part, no crossing).

INSTALLATION (about 2 minutes)
1. Close Proteus. Extract the WHOLE ZIP to a normal folder (e.g. Desktop).
2. Copy everything in "Proteus Library Files" (TEPAIRCORE.LIB and our Arduino
   library V4.0, ArduinoV4TEP.LIB) to the LIBRARY folder of Proteus, for
   example:
     C:\Program Files (x86)\Labcenter Electronics\Proteus 8 Professional\LIBRARY
   (on some PCs: C:\ProgramData\Labcenter Electronics\Proteus 8 Professional\
   LIBRARY - use the folder that already holds Proteus's own .LIB files).
3. Copy TEPAIRCORE.DLL and TEPARDUINO.DLL from "Proteus Model Files" to the
   MODELS folder (...\Proteus 8 Professional\MODELS). The demo's driver is NOT
   in this package: install our L9110S Motor Driver library the same way (its
   own ZIP - see IMPORTANT LINKS): TEPL9110S.LIB and TEPL9110S.DLL.
4. Delete TEPAIRCORE.IDX from the LIBRARY folder if it is there.
5. Start Proteus. In Pick Devices (P) search "air-core".

RUN THE DEMO
"Proteus Simulation\Air-Core-Gauge-L9110S-ArduinoUnoV4.pdsprj" - keep the .hex
file and the DLLs beside the project (with the L9110S library installed).
  ARD1: Arduino UNO V4.0 running AirCore_Gauge_Demo.hex, its serial monitor
        built in (window "TEP Arduino UNO - ARD1").
  DRV1: our L9110S driver (pop-up version, a separate library): B-IA on D9,
        B-IB on D10, A-IA on D5, A-IB on D6, VCC on +12V, GND - by net labels.
  M1:   the gauge: COS+ / COS- on the L9110S's B-OA / B-OB (motor B), SIN+ /
        SIN- on A-OA / A-OB (motor A) - straight wires.
  RV1:  10k pot on A0 (the r/min in knob mode).
  1. Press Run. The monitor and the two pop-ups open (move them aside). The
     needle sweeps to the end and back, then follows RV1.
  2. Turn RV1. Type in the monitor and press Send: rpm 6800, jump 7000, rpm
     3000, weak 15, full, angle 300, off, on, sweep, rev.
  3. Click the dial: a finger holds the needle. The pop-up's Tap chip knocks
     the gauge.
  4. Double-click M1: RANGE (e.g. 12000), REDLINE, RETURN NO.
  5. The pop-up: Gauge, Graphs, Event log, Check.

WIRING (the same idea on a real gauge)
  L9110S          Arduino UNO / supply
   B-IA, B-IB     D9, D10 (PWM): the COS coil
   A-IA, A-IB     D5, D6 (PWM): the SIN coil
   VCC            12 V (the L9110S takes 2.5 - 12 V; its inputs stay 5 V
                  logic), GND to the UNO's GND
  Gauge           L9110S
   COS+ / COS-    B-OA / B-OB
   SIN+ / SIN-    A-OA / A-OB
In the sketch (no library needed): for each coil a PWM on one input and LOW on
the other; the sign of cos / sin picks the input:
  coil(cos(angle), COS_A, COS_B);   // analogWrite(COS_A, |x| * 255) or (COS_B)
  coil(sin(angle), SIN_A, SIN_B);
REAL HARDWARE:
 * Car air-core gauges are 12 V parts with 200 - 250 ohm coils: 50 - 60 mA a
   coil - an H-bridge (L9110S, L293D, L298N) or a gauge driver chip (CS4192,
   CS8190); never straight from a microcontroller pin.
 * Find the coils with a meter: two pairs of terminals, about 230 ohm each.
   If the needle turns the wrong way, swap the two wires of one coil.
 * Move the field in steps (a few degrees every 10 ms): a jump of more than
   180 deg sends the magnet the short way round.
 * Keep cos^2 + sin^2 near 1: the field stays the same size and the needle
   equally firm all round the dial.

THE DEMO SKETCH ON THE SERIAL MONITOR (AirCore_Gauge_Demo V1.0, 9600 baud)
  rpm 3500   show 3500 r/min          knob      follow RV1
  sweep      0 - 8000 - 0             rev       a blip: 900 - 6800 - 900
  jump 7000  jump there at once (more than 180 deg: stuck at the pin)
  angle 300  the field to 300 deg (past the scale)
  weak 20    the field at 20 %        full      the field at 100 %
  off / on   the coils off (the return magnet takes the needle to 0) / on
  help       the list
EXPECTED MONITOR OUTPUT
  Air-Core Gauge demo - The Engineering Projects
  L9110S on 12 V: COS coil on motor B (D9 / D10), SIN coil on motor A (D5 / D6).
  Self-test sweep, then the knob (RV1).
  Commands: rpm 3500 | knob | sweep | rev | jump 7000 | angle 300 | weak 20 | full | off | on | help
  Sweep done - the knob

PROPERTIES (double-click the part > Edit Properties)
  RANGE      r/min at the end of the 270 deg scale (2000 - 20000; default
             8000 - the dial numbers in thousands)
  REDLINE    where the red zone starts (default 6500)
  RETURN     YES: the return magnet (with the coils off the needle sinks back
             to 0); NO: none (default YES)
Every run starts again from the properties.

TROUBLESHOOTING
* The needle does not move (OFF): no coil current - the L9110S has no 12 V, or
  its inputs are not driven.
* It points the wrong way, or turns backwards: one coil's wires are swapped,
  or COS and SIN are swapped - the Check page and the field vector show it.
* It sits on the pin and will not come up (STUCK AT THE PIN): the field jumped
  more than 180 deg - slew it in steps.
* It reads low and sluggish (WEAK FIELD): too little current - a low supply,
  or cos / sin scaled down.
* "only the COS coil carries current": the SIN coil (or its H-bridge) is not
  connected.
* The part is not simulated: TEPAIRCORE.DLL is missing from MODELS and from
  the project folder. No driver: install our L9110S library (TEPL9110S.LIB /
  .DLL). No UNO / no monitor window: TEPARDUINO.DLL, or click the UNO's USB
  port.
* The pop-up does not appear: click OPEN PANEL on the strip, or turn "Open the
  panel at Run" on its Settings page back on.

BUG REPORTS AND FEATURE REQUESTS
Please post them in our forum with a screenshot, the Serial Monitor text, the
simulation log and the pop-up's Copy diagnostics text:
  https://www.theengineeringprojects.com/forum/category/motor-driver-proteus-library

SUPPORT US
This library is free. If it saves you time, please support our work:
  https://www.theengineeringprojects.com/donate

LICENCES AND THIRD-PARTY NOTES
* The gauge model (TEPAIRCORE.DLL), the symbol and artwork and the Arduino
  Library V4.0 (ArduinoV4TEP.LIB / TEPARDUINO.DLL) are made by The Engineering
  Projects. The model is an independent implementation written from the
  typical data of automotive air-core gauge movements. The models use only
  standard Windows libraries; no Visual C++ redistributable is needed.
  The C++ source code is not included. The demo's driver, our L9110S Motor
  Driver library (TEPL9110S.LIB / TEPL9110S.DLL), is a separate download.
* The demo's .hex is built from the demo sketch and the Arduino AVR core 1.8.6,
  which includes LGPL-licensed code; its source code is available at
  https://github.com/arduino/ArduinoCore-avr/tree/1.8.6
* Proteus is a product of Labcenter Electronics and is not included. Arduino is
  a trademark of Arduino SA. This library is not made or endorsed by any gauge
  maker, Arduino or Labcenter.

REBUILDING THE FIRMWARE (OPTIONAL)
The HEX file is supplied; Arduino IDE is not needed to run the demo. To edit
the sketch, open Arduino Code\AirCore_Gauge_Demo\AirCore_Gauge_Demo.ino, select
Arduino Uno and use Sketch > Export Compiled Binary. The sketch needs 9,070
bytes of flash (28 % of the UNO) and 316 bytes of RAM.

MODEL SCOPE AND LIMITS
Modelled: the two coils (resistance, inductance, the magnet's back-EMF), the
needle's torque from the field, the fluid damping, the pivot friction, the
return magnet, the stop pin (stuck after a jump of more than 180 deg), the
weak field, the finger and the tap, the over-current and dead-coil warnings.
How it runs: each coil is in the circuit as its backward-Euler companion over
the analog step (a conductance and a source); the needle runs in 100 us steps
between the analog points, which are held to 200 us while the needle moves or
a current changes (2 ms at rest). The field and the needle's speed are judged
from the currents averaged over 10 ms (a PWM straight on the coils is felt as
its average).
Not modelled: the temperature drift of the coils and of the fluid, the
magnet's cogging, a pointer's mechanical imbalance.

VERSION
TEP Air-Core Gauge library V1.0 (Oct 2026). Device AIRCORETEP
(TEPAIRCORE.LIB / TEPAIRCORE.DLL). Demo sketch AirCore_Gauge_Demo V1.0. Demo
driver: L9110SADVTEP (TEP L9110S Motor Driver library V1.0, a separate
library). Demo board: ARDUINO UNO V4.0 (TEP Arduino Library V4.0) with its
built-in serial monitor.