Automotive Telematics Design

flux

Work done
  • Added automotive input + protection: J1, D1 (1N4007 series), D3 (TVS)
  • Wired buck + 5V rail + bulk cap: PS1 -> ^+5V with C1 470uF
  • Implemented and wired sensing:
    • Fuel follower: U4 -> U1 GPIO34 (D34)
    • Fuel pull-up + isolation: R1 10k + D6 (Schottky) to fuel input J3
    • Ignition divider to GPIO35: J2 + R3 10k / R4 4.7k
    • Tamper header + pull-up to GPIO13: J4 + R5 10k
  • Verified UART mappings:
    • SIM800L U3: TXD->ESP32 RX2(GPIO16), RXD->ESP32 TX2(GPIO17)
    • NEO-6M U2: TX->GPIO21, RX->GPIO22
  • Set layout baseline: 2-layer 1.6mm FR4 stackup + default 10 mil trace width
Success criteria review
  • ✅ ESP32 DevKit-V1 + power regulation + sensing circuits implemented and wired per values/mapping
  • ✅ ERC “Missing Power” cleared (added PowerNet1 to satisfy symbol check)
  • ❌ PCB constraints not fully enforceable yet: Flux DRC still reports Airwires (37) because routing (and copper pours/keepouts/via stitching) cannot be executed by me in this environment
Next steps
  • In PCB editor, run Auto-Layout / route the 37 airwires, then I can re-check DRC.
  • If you share the antenna keepout dimensions/regions (or a board outline file), I can help define exact keepout polygons and confirm the rules once those layout primitives exist.
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U3
U1
U1 RX2 - U3 TXD
J1
U1 GND_1 - U3 GND
C1
Capacitance
470uF
U1 GND_1 - U3 GND
U1 RX2 - U3 TXD
R3
Resistance
10kΩ
U4
J4 1 - R5 P2
R1
Resistance
10kΩ
R1 P2 - D6 A
J1 1 - D1 anode
GND
U1 GND_1 - U3 GND
D6 C - U4 +IN 1
J2 1 - R3 P1
GND
R4
Resistance
4.7kΩ
U1 TX2 - U3 RXD
U1 3V3 - R1 P1
R17
Resistance
500 Ω
J1 1 - D1 anode
J2
U1 GND_1 - U3 GND
R5
Resistance
10kΩ
J2 1 - R3 P1
U1 TX2 - U3 RXD
U1 GND_1 - U3 GND
R3 P2 - R4 P1
U1 GND_1 - U3 GND
U1 GND_1 - U3 GND
R3 P2 - R4 P1
J4 1 - R5 P2
J1 1 - D1 anode
GND
R2
Resistance
500 Ω
J1 1 - D1 anode
U1 3V3 - R1 P1
R3 P2 - R4 P1
PS1 OUT + - U1 VIN
PS1 OUT + - U1 VIN
J4
PS1 OUT + - U1 VIN
U1 GND_1 - U3 GND
U1 3V3 - R1 P1
R1 P2 - D6 A
D6 C - U4 +IN 1
J1 1 - D1 anode
U4 OUT 1 - U1 D34
J3
PS1
D3
D6
C3
D1

Fuel Sentinel V1 - Automotive Telematics & Fuel Security

Fuel Sentinel V1 - Automotive Telematics & Fuel Security thumbnail
Fuel Sentinel V1 - Automotive Telematics & Fuel Security

Properties

Diagram



  
    
  
  
    
  























UART

UART













"Car battery node_12V input"
"Reverse diode + TVS"
"LM2596 buck node_5V node_3A"
"5V rail"
"ESP32 DevKit V1"
"SIM800L"
"NEO-6M"
"Ignition sense divider"
"Fuel sender line"
"LM358 follower (IGN on)"
"3.3V pullup via Schottky (IGN off)"
"Tamper switch header"
"Common GND"

Pricing & Availability

Distributor

Qty 1

Arrow

$1.43–$2.79

Digi-Key

$5.83–$7.02

LCSC

$11.42–$11.53

Mouser

$4.29

TME

$3.55

Verical

$1.23–$3.20

Controls