# Universal Inline Analog Signal Conditioner ## Description ESP32-based universal inline analog signal conditioner with protected sensor input, DAC output, fail-safe NC relay passthrough, OLED UI, Bluetooth profile logic, and terminal-block I/O for automotive/bench use. ## Project Details - **Owner:** ricomans - **Created:** 5/16/2026 - **Last Updated:** 5/16/2026 - **Visibility:** Public ## Key Components ### D1 — [1N4007RLG](https://www.flux.ai/jecstronic/1n4007rlg~07j.md) - Datasheet URL: https://www.onsemi.com/pdf/datasheet/1n4001-d.pdf - Role Details: Series diode from J3 12V input to protected 12V rail - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Diode - Role: Reverse Polarity Protection - Manufacturer Name: onsemi - Manufacturer Part Number: 1N4007RLG **Pins:** - anode [pin 2] - cathode [pin 1] ### D2 — [1N4148-1](https://www.flux.ai/gaby27/1n4148-1~89.md) - Datasheet URL: https://www.mouser.com/datasheet/2/308/1N914_D-1801484.pdf - Role Details: Upper clamp diode from protected analog input to 5V_REF - Part Type: Diode - Manufacturer Part Number: 1N4148-1 - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: Microchip - Role: Input Clamp **Pins:** - A [pin 2] - K [pin 1] ### D3 — [1N4148-1](https://www.flux.ai/gaby27/1n4148-1~89.md) - Manufacturer Part Number: 1N4148-1 - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.mouser.com/datasheet/2/308/1N914_D-1801484.pdf - Part Type: Diode - Role: Input Clamp - Role Details: Lower clamp diode from GND to protected analog input - Manufacturer Name: Microchip **Pins:** - A [pin 2] - K [pin 1] ### D4 — [1N4007RLG](https://www.flux.ai/jecstronic/1n4007rlg~07j.md) - Manufacturer Name: onsemi - Manufacturer Part Number: 1N4007RLG - Role Details: Protects Q1 from relay coil inductive kick - Role: Flyback Diode - Part Type: Diode - Datasheet URL: https://www.onsemi.com/pdf/datasheet/1n4001-d.pdf - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - anode [pin 2] - cathode [pin 1] ### J1 — [282837-3](https://www.flux.ai/adrian95/282837-3~5mc.md) - Role: Input Connector - Role Details: Pin 1 SIG IN, Pin 2 5V REF, Pin 3 GND - Datasheet URL: https://www.te.com/usa-en/product-282837-3.datasheet.pdf - Part Type: Connector - Manufacturer Name: TE Connectivity AMP Connectors - Manufacturer Part Number: 282837-3 - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] - Pin_3 [pin 3] ### J2 — [282837-3](https://www.flux.ai/adrian95/282837-3~5mc.md) - Role Details: Pin 1 SIG OUT, Pin 2 5V REF, Pin 3 GND - Role: Output Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: TE Connectivity AMP Connectors - Manufacturer Part Number: 282837-3 - Part Type: Connector - Datasheet URL: https://www.te.com/usa-en/product-282837-3.datasheet.pdf **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] - Pin_3 [pin 3] ### J3 — [KF128-5.08-2P-AA](https://www.flux.ai/lcsc/kf128-5p08-2p-aa~0pbi.md) - Product Info Url: https://lcsc.com/product-detail/New-Quadratic-Unclassified-Data_Cixi-Kefa-Elec-KF128-5-08-2P_C474952.html - Connector Type: Screw terminal - Role: Power Input Connector - Connector Gender: Female - JLCPCB Part Class: Extended Part - Package or Case Code: CONN-TH_P5.08_KF128-5.08-2P - LCSC Part Number: C474952 - Current Rating: 24A - Connector Positions: 2 - Connector Rows: 1 - Part Type: Screw terminal - Manufacturer Name: KEFA(科发) - Connector Pitch: 5.08mm - Operating Temperature: -40℃~+105℃ - Manufacturer Part Number: KF128-5.08-2P-AA - Role Details: Pin 1 12V DC input, Pin 2 GND - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2408211511_Cixi-Kefa-Elec-KF128-5-08-2P-AA_C474952.pdf **Pins:** - 1 [pin 1] - 2 [pin 2] ### K1 — [PR2-5V-450-1C](https://www.flux.ai/adrian95/pr2-5v-450-1c~nlr.md) - Role Details: NC contact wired for raw signal passthrough; coil energized only after ESP32 firmware is running - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Relay - Role: Fail-Safe Relay - Datasheet URL: https://www.cuidevices.com/product/resource/pr2.pdf - Manufacturer Name: CUI Devices - Manufacturer Part Number: PR2-5V-450-1C **Pins:** - COIL_1 [pin 1] - COIL_2 [pin 2] - COM [pin 3] - NC [pin 5] - NO [pin 4] ### Q1 — [2N2222A](https://www.flux.ai/lcsc/2n2222a~00rk.md) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/1809200018_ST-Semtech-2N2222A_C118536.pdf - Product Info Url: https://lcsc.com/product-detail/Transistors-NPN-PNP_2N2222_C118536.html - LCSC Part Number: C118536 - Compliance: RoHS - Manufacturer Part Number: 2N2222A - Transistor Type: NPN - Part Type: Transistors/Thyristors/Bipolar (BJT) - Role Details: Switches 5V relay coil current; driven through PC817 output and base resistor - JLCPCB Part Class: Extended Part - Package or Case Code: TO-92-3_L4.9-W3.7-P1.27-L - Manufacturer Name: ST(先科) - Role: Relay Driver - Frequency: 250MHz **Pins:** - B [pin 2] - C [pin 3] - E [pin 1] ### S1 — [OEM B3F-4055](https://www.flux.ai/dany3/oem-b3f-4055~vl.md) - Manufacturer Name: OEM Generic - Part Type: Switch - Datasheet URL: https://omronfs.omron.com/en_US/ecb/products/pdf/en-b3f.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: OEM B3F-4055 - Role Details: Profile up tactile pushbutton - Part Type: {"type":"vector3","data":{"x":0,"y":0,"z":0}} - Role: Button **Pins:** - A [pin 1] - A1 [pin 2] - B [pin 3] - B1 [pin 4] ### S2 — [OEM B3F-4055](https://www.flux.ai/dany3/oem-b3f-4055~vl.md) - Part Type: Switch - Datasheet URL: https://omronfs.omron.com/en_US/ecb/products/pdf/en-b3f.pdf - Manufacturer Name: OEM Generic - Manufacturer Part Number: OEM B3F-4055 - Role Details: Profile down tactile pushbutton - License: https://creativecommons.org/licenses/by/4.0/ - Role: Button - Part Type: {"data":{"x":0,"y":0,"z":0},"type":"vector3"} **Pins:** - A [pin 1] - A1 [pin 2] - B [pin 3] - B1 [pin 4] ### U1 — [ESP32-DEVKITC](https://www.flux.ai/vasy_skral/esp32-devkitc~7mc.md) - Part Type: Development Boards - Datasheet URL: http://espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf - Manufacturer Part Number: ESP32-DEVKITC - Role: MCU - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: Espressif Systems - Symbol Style: Parametric - Role Details: ESP32 DevKitC controller; use ADC1 for buffered sensor input, I2C for DAC/OLED, GPIOs for buttons and relay enable **Pins:** - 3V3 [pin 1] - CLK [pin 20] - CMD [pin 18] - EN [pin 2] - EXT_5V [pin 19] - GND1 [pin 14] - GND2 [pin 32] - GND3 [pin 38] - IO0 [pin 25] - IO12 [pin 13] - IO13 [pin 15] - IO14 [pin 12] - IO15 [pin 23] - IO16 [pin 27] - IO17 [pin 28] - IO18 [pin 30] - IO19 [pin 31] - IO2 [pin 24] - IO21 [pin 33] - IO22 [pin 36] - IO23 [pin 37] - IO25 [pin 9] - IO26 [pin 10] - IO27 [pin 11] - IO32 [pin 7] - IO33 [pin 8] - IO34 [pin 5] - IO35 [pin 6] - IO4 [pin 26] - IO5 [pin 29] - RXD0 [pin 34] - SD0 [pin 21] - SD1 [pin 22] - SD2 [pin 16] - SD3 [pin 17] - SENSOR_VN [pin 4] - SENSOR_VP [pin 3] - TXD0 [pin 35] ### U2 — [LM358_2247708](https://www.flux.ai/texas-instruments/lm3582247708~ex.md) - Role Details: LM358 powered from protected 12V so 0.3V-4.7V sensor input is within input common-mode range - Role: Analog Buffer - Package or Case Code: DIP8_300 - Manufacturer Part Number: LM358 **Pins:** - 2 [pin 2] - 6 [pin 6] - 4 [pin 4] - 3 [pin 3] - 1 [pin 1] - 5 [pin 5] - 8 [pin 8] - 7 [pin 7] ### U3 — [MCP4725A1T-E-CH](https://www.flux.ai/jecstronic/mcp4725a1t-e-ch~1ah.md) - Manufacturer Part Number: MCP4725A1T-E/CH - Datasheet URL: http://www.microchip.com/mymicrochip/filehandler.aspx?ddocname=en532676 - Role: DAC - Manufacturer Name: Microchip - Part Type: Integrated Circuit - Role Details: MCP4725 12-bit I2C DAC, VDD=5V reference, A0 tied to GND, VOUT drives output relay path; replaces U3 breakout module. **Pins:** - A0 - GND - SCL - SDA - VDD - VOUT ### U5 — [LM7805CT/NOPB](https://www.flux.ai/adrian95/lm7805ctnopb~wo3.md) - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Integrated Circuit - Datasheet URL: https://www.ti.com/lit/ds/symlink/lm340.pdf - Role Details: 12V to 5V linear regulator; design current about 624mA peak, thermal dissipation documented in power-analysis - Role: Voltage Regulator - Manufacturer Name: Texas Instruments - Manufacturer Part Number: LM7805CT/NOPB **Pins:** - GND [pin 2] - VI [pin 1] - VO [pin 3] ### U6 — [PC817](https://www.flux.ai/kicad-part-library/pc817~0c.md) - Datasheet URL: http://www.soselectronic.cz/a_info/resource/d/pc817.pdf - Role: Optocoupler - Role Details: GPIO-controlled relay enable isolation/drive interface - Package or Case Code: DIP-4_W7.62mm - Manufacturer Part Number: PC817 **Pins:** - ~ [pin 1] - ~ [pin 3] - ~ [pin 2] - ~ [pin 4] ### U7 — [Logic Level Converter](https://www.flux.ai/diamond91/logic-level-converter~nm.md) - Role Details: Protects ESP32 3.3V GPIO while allowing 5V-powered MCP4725 output range - Role: Logic-level Shifting - Manufacturer Name: Generic / SparkFun-compatible - Manufacturer Part Number: BSS138 I2C Logic Level Converter Module **Pins:** - GND [pin GND_1] - GND [pin GND_2] - HV [pin HV] - HV1 [pin HV1] - HV2 [pin HV2] - HV3 [pin HV3] - HV4 [pin HV4] - LV [pin LV] - LV1 [pin LV1] - LV2 [pin LV2] - LV3 [pin LV3] - LV4 [pin LV4] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/ricomans/universal-inline-analog-signal-conditioner~tt](https://www.flux.ai/ricomans/universal-inline-analog-signal-conditioner~tt).* --- *Generated from [https://www.flux.ai/ricomans/universal-inline-analog-signal-conditioner~tt](https://www.flux.ai/ricomans/universal-inline-analog-signal-conditioner~tt)*