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''LIGO AIR User Guide v1.2 — Wireless Fuel Level Sensor''
''Document version: 1.2 | Date: 04/11/2025 | Language: English''

== Safety Information ==

'''Read this section completely before installation or operation.''' Failure to observe these warnings may result in serious injury, death, or damage to equipment.

The LIGO AIR fuel level sensor must be installed and operated only by '''qualified technicians''' familiar with fuel tank systems, electrical safety, and wireless device installation. Personal Protective Equipment (PPE) is required during installation.
{{Danger
| title = Fire / Explosion Hazard
| body = *'''Hazard''': Fuel vapors are highly flammable and can ignite from sparks, open flames, or static electricity
*'''Consequence''': Serious injury, death, or destruction of vehicle/equipment
*'''Required action''': Before drilling or installation, '''completely empty the fuel tank''' and ventilate all residual vapors. Use only non-sparking tools. Maintain fire extinguisher within 5 meters. No smoking or open flames within 10 meters of work area.
}}
== Product Overview ==

The LIGO AIR is a '''wireless fuel level sensor''' designed and manufactured by SOJI Electronics for measuring the level of liquid fuel and other non-conductive liquids in vehicle tanks and stationary fuel storage applications.

Equipped with '''Bluetooth Low Energy 5.4''' technology, LIGO AIR enables seamless, real-time data transmission without requiring complex wiring. The heavy-duty metal structure provides protection against dust, moisture, vibration, and high-temperature environments.

=== Intended Use ===

LIGO AIR is intended for:

* Fuel level measurement in '''diesel, gasoline, and non-conductive liquid tanks'''
* Mobile applications: trucks, excavators, cement mixers, construction machinery
* Stationary applications: marine vessels, generators, industrial oil storage tanks
* Off-highway machinery in harsh environments

=== Product Variants ===

{| class="wikitable"
! Variant !! Description !! Battery Life !! Range
|-
| LIGO AIR LxS || Standard cost-effective version || 6–8 years || Standard
|-
| LIGO AIR LxT || Extended-battery version || '''8–12 years''' || Standard
|-
| LIGO AIR PRO || Long-range version (high TX power) || 6–8 years || '''2× Standard'''
|}

== Package Contents ==

Each LIGO AIR shipment includes:

{| class="wikitable"
! No. !! Item !! Quantity
|-
| 1 || LIGO AIR Fuel Level Sensor (700/1000/1500 mm standard, custom on request) || 01
|-
| 2 || Oil filter || 01
|-
| 3 || Gasoline-resistant rubber gasket || 01
|-
| 4 || Bottom-stop and springs || 01
|-
| 5 || Self-drilling screw M4.8 × 32 mm || 05
|-
| 6 || Rivet and screw M5 × 20 mm || 05
|-
| 7 || Protective cap || 01
|-
| 8 || Quick installation manual || 01
|}

'''Verify all items are present before installation.''' Contact SOJI Electronics if any item is missing or damaged.

== Specifications ==

{| class="wikitable" style="text-align:center;"
! Parameter !! LIGO AIR (LxS, LxT) !! LIGO AIR-PRO
|-
| Standard length (L), mm        || colspan="2" | 700, 1000, 1500 ... up to 6000 mm
|-
| Measuring error, %             || colspan="2" | ± 0.5 %
|-
| rowspan="2" | Bluetooth specs  || colspan="2" | ''Bluetooth'' 5.4, IEEE 802.15.4-2006, 2.4 GHz, -95 dBm sensitivity
|-
| TX power max: 6 dBm            || TX power max: '''19.5 dBm'''
|-
| Advertising Protocol           || colspan="2" | SOJI (default), Mielta, Escort — selectable in mobile app
|-
| Power supply                   || 3.6V × 2600mAh (LxS) / 2400mAh (LxT) Li-SOCl₂ || 3.6V × 3600mAh
|-
| Current (working mode), µA     || 9 || 27
|-
| Measurement interval (s)       || colspan="2" | 5 to 10
|-
| Advertising interval (s)       || 5 to 10 || 10 to 15
|-
| Ingress protection             || colspan="2" | IP69K
|-
| Operating temperature (°C)     || colspan="2" | -40 to +85
|-
| Resolution (bit)               || colspan="2" | 12
|-
| Accelerometer                  || N/A || Built-in
|-
| Memory                         || colspan="2" | Built-in 32 Mb EEPROM
|-
| Service life (expected), years || colspan="2" | 10
|-
| Storage condition              || colspan="2" | 15 °C to 30 °C, RH < 60 %
|}

=== Sensor Dimensions ===

[[File:LIGO-AIR-dimensions.png|thumb|center|500px|LIGO AIR overall dimensions (mm)]]

{| class="wikitable"
! Part Number !! Length L (mm)
|-
| LIGO AIR – L7S, L7T, LIGO AIR PRO – L7S          || 700 ± 3
|-
| LIGO AIR – L10S, L10T, LIGO AIR PRO – L10S       || 1000 ± 3
|-
| LIGO AIR – L15S, L15T, LIGO AIR PRO – L15S       || 1500 ± 3
|}

== Installation ==

'''Before installation''': Read [[#Safety Information|Safety Information]] section thoroughly.

=== Tools Required ===

* Electric drill with Ø4 mm and Ø42 mm bits
* M4.8 self-tapping screw driver (or M5 rivet tool depending on tank thickness)
* Cutting tool for sensor tube (hacksaw or pipe cutter)
* Deburring tool
* Fuel-resistant RTV silicone gasket sealant
* Mobile phone with LIGO BLE Configurator app installed
* Personal Protective Equipment (PPE): safety goggles, chemical-resistant gloves

=== Step 1: Fuel Tank Preparation ===

# Empty the fuel tank completely. For gasoline tanks, '''ventilate all fuel vapors''' to prevent fire/explosion (see [[#Safety Information|Safety]])
# Clean and dry the tank interior
# Select installation location:
#* As close as possible to the tank's '''geometric center'''
#* At the tank's '''deepest point'''
#* Avoid contact with reinforcement ribs or internal equipment

[[File:LIGO-AIR-tank-location.png|thumb|center|500px|Installation location — front, left, and top view]]

=== Step 2: Drilling Mounting Holes ===

Drill a central hole (Ø42 mm) and four mounting holes (Ø7 mm) as shown:

[[File:LIGO-AIR-drilling-pattern.png|thumb|center|500px|Drilling pattern: Ø40 center hole + 4 × Ø4 mounting holes at 70.5 × 70.5 mm spacing]]

{| class="wikitable"
! Tank wall thickness !! Fastener type !! Mounting hole
|-
| ≤ 3 mm || M5 rivet nut          || 4 × Ø7 mm
|-
| > 3 mm || M4.8 self-tapping screw || 4 × Ø7 mm
|}
{{Notice|title=Sensor Orientation|body=Mounting hole positions must ensure the sensor's '''directional arrow points toward the BLE receiver'''. Incorrect orientation will severely reduce wireless range.}}

=== Step 3: Sensor Tube Preparation ===

Cut the sensor tube to length:

  L = H − 25 mm

Where:
* '''L''' = final tube length after cutting
* '''H''' = height of the tank at the installation point

After cutting:
# Remove all burrs with deburring tool
# Clean the tube interior with fuel
{{Warning
| title = Tube Preparation
| body = Minimum tube length after cutting is '''150 mm (15 cm)'''. Shorter tubes will not function correctly.
}}

=== Step 4: Install Bottom-Stop and Filter ===

Install the bottom-stop and oil filter in sequence as shown:

[[File:LIGO-AIR-bottom-stop-filter.png|thumb|center|400px|Bottom-stop spring and oil filter installation]]

=== Step 5: Mount Sensor on Fuel Tank ===

# Apply '''fuel-resistant RTV silicone gasket sealant''' to:
#* Tank surface around the central hole
#* Gasket (both sides)
#* Sensor flange
# Insert the LIGO AIR sensor through the central hole
# Align so the directional arrow points toward the BLE receiver
# Fasten using appropriate screws (self-tapping or rivet)

[[File:LIGO-AIR-orientation-examples.png|thumb|center|600px|Correct (✓) vs incorrect (✗) sensor orientations]]

=== Step 6: Verify Installation Clearance ===

Ensure a minimum clearance of '''150 mm''' between the top of the sensor and any overhead metal surface to avoid BLE signal attenuation.

[[File:LIGO-AIR-clearance.png|thumb|center|400px|Minimum 150 mm clearance from overhead metal]]

After mounting, proceed to [[#Configuration|Configuration]].

== Configuration ==

LIGO AIR is configured via the '''LIGO BLE Configurator''' mobile application.

=== Mobile App Installation ===

Download LIGO BLE Configurator from:

* '''iOS''': App Store
* '''Android''': Google Play

After installation, '''grant all permissions''' requested by the app:

* Camera (for QR code scanning)
* Location (required by Android for BLE scanning)
* Nearby devices / Bluetooth

[[File:LIGO-AIR-app-permissions.png|thumb|center|400px|Granting app permissions]]

=== Connecting to the Sensor ===

# Open the LIGO BLE Configurator app
# Tap '''LIGO AIR''' in the product list
# Scan the area — the app will list discovered sensors
# Tap '''Connect''' next to the desired sensor

Each sensor shows:
* Name (e.g., LIGO AIR_7EEF7E7F)
* RSSI (signal strength, should be ≥ -80 dBm)
* Temperature
* Current fuel level
* Battery voltage (Vbat)
* Firmware version (FW)

[[File:LIGO-AIR-device-list.png|thumb|center|400px|Selecting LIGO AIR from device list]]

=== Calibration: Set Empty / Set Full ===

After installation, calibrate the sensor:

==== Step 1: Set Full ====

# Immerse the sensor in fuel until fuel reaches the sensor flange
# Wait for '''C_working''' value to stabilize (~30 seconds)
# Press '''Set Full''' button in the app

[[File:LIGO-AIR-set-full.png|thumb|center|400px|Set Full procedure]]

==== Step 2: Set Empty ====

# Remove the sensor from fuel
# Wait '''1–2 minutes''' for fuel to drain from the measuring probe
# Press '''Set Empty''' button in the app

[[File:LIGO-AIR-set-empty.png|thumb|center|400px|Set Empty procedure]]

=== Configurable Parameters ===

{| class="wikitable"
! Parameter !! Default !! Range / Options
|-
| Device name             || LIGO AIR_<MAC> || Customizable
|-
| Advertising protocol    || SOJI           || SOJI / Mielta / Escort
|-
| Measurement interval    || 5–10 s         || 5 to 60 s
|-
| Advertising interval    || 5–10 s         || 5–10 s (LIGO AIR), 10–15 s (PRO)
|-
| Output mode             || 0–4095 raw     || 0–1023 raw / 0–4095 raw / Liters
|-
| Password                || (default)      || '''CHANGE before deployment'''
|}
{{Notice|title=Security Recommendation|body=Change the default password immediately after first connection to prevent unauthorized configuration changes.}}

== Operation ==

After installation and calibration, LIGO AIR operates autonomously, transmitting fuel level data via BLE advertising packets at configured intervals.

=== Calibration Table ===

LIGO AIR supports two calibration methods:

{| class="wikitable"
! Method !! Description !! Recommended
|-
| '''On Platform (Server)''' || Sensor sends raw values (0–4095). Server converts to volume (liters) using calibration table. || ✓ '''Recommended'''
|-
| '''On Sensor''' || Sensor sends volume values directly using internal calibration table. ||
|}

The manufacturer recommends '''platform calibration''' for fleet management scenarios because:
* Single source of truth on the server
* Easier to update calibration across multiple sensors
* Reduces sensor memory load

=== Reading Sensor Data ===

LIGO AIR data is received by:

* '''Telematics device''' (FM tracker) with BLE scanning
* '''Smartphone''' with LIGO BLE Configurator app

For protocol integration details, see [[LIGO Air Configuration#Protocol Integration|Protocol Integration]].

=== Long-Range Operation ===

For challenging environments (long distance, metal obstacles):

{| class="wikitable"
! Combination !! Range
|-
| LIGO AIR + Telematics device      || Standard
|-
| LIGO AIR + LIGO AIR Adapter       || '''2× Standard'''
|-
| LIGO AIR PRO + LIGO AIR Adapter   || '''4× Standard'''
|}

=== Installing the Protective Cap ===

After installation and calibration are complete, install the protective cap to prevent unauthorized access and protect against environmental damage.

[[File:LIGO-AIR-cap-install.png|thumb|center|400px|Push the cap until it clicks into place]]

For inspection, remove the cap as shown:

[[File:LIGO-AIR-cap-removal.png|thumb|center|500px|Correct (✓) vs incorrect (✗) cap removal procedure]]

== Troubleshooting ==

{| class="wikitable"
! Symptom !! Possible Cause !! Solution
|-
| Sensor not found in app's device list
|
* Bluetooth disabled on phone
* Sensor in storage mode (not yet activated)
* Sensor out of range (>50 m)
* Metal obstruction blocking signal
|
* Enable Bluetooth, restart app
* Move within 1 m of sensor and retry
* Use LIGO AIR Adapter to boost reception
* Verify orientation (directional arrow toward receiver)
|-
| Connection drops frequently
|
* RSSI weaker than -80 dBm
* High RF interference (other 2.4 GHz devices)
* Tank metal interference
|
* Reposition receiver closer
* Use LIGO AIR PRO + Adapter
* Reorient sensor (arrow toward receiver)
|-
| Fuel reading inaccurate
|
* Calibration error
* Sensor tube damaged or bent
* Filter clogged with debris
* Wrong calibration table on platform
|
* Recalibrate using Set Empty / Set Full
* Inspect probe, replace if bent
* Clean or replace oil filter
* Verify calibration table values
|-
| Reading shows fixed value (no change)
|
* Sensor electronics frozen
* Storage mode not deactivated
|
* Disconnect and reconnect via app
* Power-cycle by removing/inserting battery
|-
| Battery voltage drops rapidly
|
* Battery near end of life (8+ years)
* Measurement interval too short
* Operating in temperature extremes
|
* Replace battery (see [[#Maintenance|Maintenance]])
* Increase measurement interval
* Verify operating temperature within range
|-
| Sensor reports incorrect temperature
|
* Sensor near heat source (engine, exhaust)
* Sensor still warming up after installation
|
* Relocate sensor away from heat sources
* Wait 10 minutes for thermal equilibrium
|-
| App permission denied
|
* Camera/Location/Bluetooth permissions not granted
|
* Phone Settings → Apps → LIGO BLE Configurator → Permissions → Grant all
|-
| Forgot password
|
* Custom password set, then lost
|
* Contact SOJI Support (proof of ownership required for reset)
|}

If problem persists after troubleshooting, contact [[#Support / Contact|Support]].

== Maintenance ==

=== Periodic Inspection ===

{| class="wikitable"
! Frequency !! Action
|-
| '''Monthly'''   || Verify sensor reports data via mobile app or telematics platform
|-
| '''Quarterly''' || Check protective cap integrity. Verify mounting screws still secure.
|-
| '''Annually'''  || Remove sensor, clean filter, inspect probe for damage. Verify gasket seal still functional.
|-
| '''Every 5 years''' || Check battery voltage trend. If below 3.4V consistently, plan battery replacement.
|-
| '''Every 8–10 years''' || Replace battery (Li-SOCl₂ 3.6V).
|}

=== Cleaning ===

# Disconnect sensor from fuel tank (drain tank if necessary)
# Wipe external surface with dry cloth or cloth lightly dampened with non-conductive cleaner
# Do '''NOT''' use:
#* Solvents (acetone, benzene)
#* Abrasive materials
#* High-pressure water beyond IP69K rating
# Inspect and clean the oil filter — replace if clogged
# Reinstall with new gasket sealant

=== Battery Replacement ===
{{Warning
| title = Battery Replacement Safety
| body = *Replace only with authorized '''SOJI Li-SOCl₂ 3.6V''' battery (part numbers vary by variant)
*Disconnect sensor from fuel tank before opening
*Ensure work area is ventilated and free of ignition sources
*Wear chemical-resistant gloves
}}
# Remove protective cap
# Loosen 4 mounting screws (do not remove from tank)
# Lift sensor housing off the tank
# Open battery compartment per technical instruction
# Remove old battery — '''observe polarity'''
# Install new battery — match polarity markers
# Close battery compartment
# Reassemble sensor and verify operation with mobile app

=== Calibration Verification ===

After any maintenance involving probe replacement or modification, '''re-perform Set Empty / Set Full calibration''' (see [[#Configuration|Configuration]]).

=== Disposal / End-of-Life ===

LIGO AIR contains a lithium battery and electronic components subject to WEEE (Waste Electrical and Electronic Equipment) regulations.

# Remove battery and dispose separately at certified battery recycling facility
# Send sensor body to electronic waste recycling
# Do NOT dispose in regular trash or landfill
# In EU: Take-back via local WEEE registration scheme

== Certification / Compliance ==

LIGO AIR is manufactured to meet international standards and regulations.

=== Wireless / Radio ===

{| class="wikitable"
! Region !! Standard / Approval
|-
| EU       || RED 2014/53/EU, EMC 2014/30/EU
|-
| US       || FCC Part 15.247
|-
| Canada   || ISED RSS-247, RSS-Gen, ICES-003
|-
| UK       || UKCA, UK RED
|-
| Japan    || MIC (Telec)
|}

=== Environmental ===

{| class="wikitable"
! Standard !! Status
|-
| RoHS 3 (2011/65/EU + 2015/863) || Compliant
|-
| REACH (EU Regulation 1907/2006) || Compliant
|-
| WEEE (2012/19/EU)               || Registered
|-
| Battery WEEE (2006/66/EC)        || Registered
|}

=== Mechanical ===

{| class="wikitable"
! Standard !! Rating
|-
| IEC 60529 (Ingress Protection)   || IP69K
|}

=== Bluetooth Qualification ===

* Bluetooth Core Specification: 5.4
* Bluetooth SIG Member ID: ''(see [[LIGO Air Memberships]])''
* End Product Declaration ID: ''(see [[LIGO Air Memberships]])''

''Detailed certification information: see [[LIGO Air Certification & Approvals]]''
''Memberships information: see [[LIGO Air Memberships]]''

=== Warranty ===

* Warranty period: '''3 years''' from date of shipment
* Battery NOT covered by warranty
* Warranty void if:
** Operating conditions exceed specifications
** Unauthorized modification or repair
** Damage from improper installation
** Damage from chemical exposure outside rated fluids

Contact SOJI Electronics for warranty claims.

== Support / Contact ==

For technical assistance, warranty claims, or product inquiries:

{| class="wikitable"
! Channel !! Contact
|-
| Website    || [https://sojielectronics.com sojielectronics.com]
|-
| Email      || support@sojielectronics.com
|-
| Phone      || ''(insert customer support number)''
|-
| Address    || ''(insert SOJI Electronics JSC address)''
|}

=== Related Pages ===

* [[LIGO AIR]] — Product overview
* [[LIGO AIR Datasheet]] — Detailed BLE protocol, payload format
* [[LIGO AIR Certification & Approvals]] — Full certification list
* [[Frequently Asked Questions - FAQ]] — Common questions



[[Category:LIGO AIR]]