# Unemployed Azure Point-of-view gun ## Description Low-voltage energy meter front-end (ESP32 + ACS712 + 9VAC sense) ## Project Details - **Owner:** talalabuhijleh - **Created:** 3/13/2026 - **Last Updated:** 3/13/2026 - **Visibility:** Public - **System Architecture:** flowchart TD subgraph LV_PCB [Low voltage PCB only] J_VAC["9VAC input terminal"] --> VDIV["Divider + AC coupling + bias"] VDIV --> V_ADC["RC filter + clamp"] V_ADC --> ADC_V["ESP32 GPIO34 ADC"] ACS["ACS712 current sensor"] --> I_SCALE["Scale trim + AC coupling + bias"] I_SCALE --> I_ADC["RC filter + clamp"] I_ADC --> ADC_I["ESP32 GPIO35 ADC"] ESP["ESP32 DevKit V1 via headers"] -->|I2C| LCD_HDR["I2C LCD header"] ESP -->|GPIO25| RELAY_HDR["Relay module header"] USB_IN["Micro USB 5V power"] --> V5["5V rail"] V5 --> ACS V5 --> LCD_HDR V5 --> RELAY_HDR ESP --> V3V3["3V3 rail"] V3V3 --> VDIV V3V3 --> I_SCALE end subgraph OFFBOARD [Off-board mains wiring only] MAINS["MAINS_L/MAINS_N"] --> LOAD["LOAD_L/LOAD_N"] end ## Key Components ### D1 — [BZT52C3V3-7-F](https://www.flux.ai/adrian95/bzt52c3v3-7-f.md) - License: https://creativecommons.org/licenses/by/4.0/ - Package: SOD-123 - Role Details: 3.3V zener clamp to protect ESP32 ADC input - Manufacturer Part Number: BZT52C3V3-7-F - Datasheet URL: https://www.diodes.com/assets/Datasheets/ds18004.pdf - Part Type: Diode - Role: Clamp - Manufacturer Name: Diodes Incorporated **Pins:** - A [pin 2] - K [pin 1] ### D2 — [BZT52C3V3-7-F](https://www.flux.ai/adrian95/bzt52c3v3-7-f.md) - Manufacturer Part Number: BZT52C3V3-7-F - Datasheet URL: https://www.diodes.com/assets/Datasheets/ds18004.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: Diodes Incorporated - Role Details: 3.3V zener clamp to protect ESP32 ADC input - Part Type: Diode - Package: SOD-123 - Role: Clamp **Pins:** - A [pin 2] - K [pin 1] ### J1 — [Pin Header 01x15 2.54mm Vertical](https://www.flux.ai/adrian95/pin-header-01x15-254mm-vertical.md) - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Role: Connector - Package: THT_2.54mm_1x15 - Role Details: ESP32 DevKit V1 30-pin header row **Pins:** - Pin_1 [pin 1] - Pin_10 [pin 10] - Pin_11 [pin 11] - Pin_12 [pin 12] - Pin_13 [pin 13] - Pin_14 [pin 14] - Pin_15 [pin 15] - Pin_2 [pin 2] - Pin_3 [pin 3] - Pin_4 [pin 4] - Pin_5 [pin 5] - Pin_6 [pin 6] - Pin_7 [pin 7] - Pin_8 [pin 8] - Pin_9 [pin 9] ### J2 — [Pin Header 01x15 2.54mm Vertical](https://www.flux.ai/adrian95/pin-header-01x15-254mm-vertical.md) - License: https://creativecommons.org/licenses/by/4.0/ - Role: Connector - Role Details: ESP32 DevKit V1 30-pin header row - Part Type: Connector - Package: THT_2.54mm_1x15 **Pins:** - Pin_1 [pin 1] - Pin_10 [pin 10] - Pin_11 [pin 11] - Pin_12 [pin 12] - Pin_13 [pin 13] - Pin_14 [pin 14] - Pin_15 [pin 15] - Pin_2 [pin 2] - Pin_3 [pin 3] - Pin_4 [pin 4] - Pin_5 [pin 5] - Pin_6 [pin 6] - Pin_7 [pin 7] - Pin_8 [pin 8] - Pin_9 [pin 9] ### J3 — [1546215-2](https://www.flux.ai/adrian95/1546215-2.md) - Manufacturer Part Number: 1546215-2 - Datasheet URL: https://www.te.com/usa-en/product-1546215-2.datasheet.pdf - Package: THT_TerminalBlock_2pos - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Name: TE Connectivity AMP Connectors - Role Details: 9VAC input from wall-wart transformer secondary - Part Type: Connector - Role: Connector **Pins:** - 1 [pin 1] - 2 [pin 2] ### J4 — [TSW-103-07-G-S](https://www.flux.ai/adrian95/tsw-103-07-g-s.md) - Role Details: Relay module interface header: 5V, GND, RELAY_CTRL - Package: THT_2.54mm_1x3 - Manufacturer Part Number: TSW-103-07-G-S - Datasheet URL: https://suddendocs.samtec.com/prints/tsw-xxx-xx-x-x-xx-xxx-footprint.pdf - Part Type: Connector - Manufacturer Name: Samtec Inc. - License: https://creativecommons.org/licenses/by/4.0/ - Role: Connector **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] - Pin_3 [pin 3] ### J5 — [Pin Header 01x04 2.54mm Vertical i2c](https://www.flux.ai/hasanbasri93/pin-header-01x04-2p54mm-vertical-i2c.md) - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Connector - Role Details: I2C LCD backpack header: SDA, SCL, 5V, GND - Role: Connector - Package: THT_2.54mm_1x4 **Pins:** - 5V [pin 1] - GND [pin 2] - SCL [pin 4] - SDA [pin 3] ### J6 — [USB3131-30-0230-A](https://www.flux.ai/adrian95/usb3131-30-0230-a.md) - Part Type: Connector - Manufacturer Name: GCT - Role: Power Input - Role Details: Micro-USB 5V input. Only VBUS and GND required; data pins left NC. - Datasheet URL: https://gct.co/files/specs/usb3131-spec.pdf - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: USB3131-30-0230-A - Package: MicroUSB_B_THT **Pins:** - 1 [pin 1] - 2 [pin 2] - 3 [pin 3] - 4 [pin 4] - 5 [pin 5] - 6 [pin 6] - 7 [pin 7] ### J7 — [2-644861-2](https://www.flux.ai/adrian95/2-644861-2.md) - Manufacturer Name: TE Connectivity AMP Connectors - Manufacturer Part Number: 2-644861-2 - License: https://creativecommons.org/licenses/by/4.0/ - Role: Connector - Package: THT_2.54mm_1x2 - Part Type: Connector - Datasheet URL: https://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=644861&DocType=Customer+Drawing&DocLang=English&PartCntxt=2-644861-2&DocFormat=pdf - Role Details: Off-board reference only: MAINS_L/MAINS_N and LOAD_L/LOAD_N. No mains routing on PCB. **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] ### J8 — [2-644861-2](https://www.flux.ai/adrian95/2-644861-2.md) - Part Type: Connector - Datasheet URL: https://www.te.com/commerce/DocumentDelivery/DDEController?Action=srchrtrv&DocNm=644861&DocType=Customer+Drawing&DocLang=English&PartCntxt=2-644861-2&DocFormat=pdf - Role Details: Off-board reference only: MAINS_L/MAINS_N and LOAD_L/LOAD_N. No mains routing on PCB. - Manufacturer Name: TE Connectivity AMP Connectors - Role: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: 2-644861-2 - Package: THT_2.54mm_1x2 **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] ### LCD1 — [WC1602A](https://www.flux.ai/jecstronic/wc1602a.md) - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: WC1602A - Role Details: 16x2 character LCD module. Electrically connected via backpack off-board; included for documentation. - Package: LCD1602_Module - Manufacturer Name: Wincom Tech - Role: Display - Datasheet URL: http://www.datasheet39.com/download.php?id=735838 - Part Type: Display Device **Pins:** - D0 [pin 7] - D1 [pin 8] - D2 [pin 9] - D3 [pin 10] - D4 [pin 11] - D5 [pin 12] - D6 [pin 13] - D7 [pin 14] - E [pin 6] - LED(-) [pin 16] - LED(+) [pin 15] - R/W [pin 5] - RS [pin 4] - VDD [pin 2] - VO [pin 3] - VSS [pin 1] ### TP1 — [1.25mm SMD Test Point](https://www.flux.ai/jharwinbarrozo/1p25mm-smd-test-point.md) - Package: SMD_TestPoint - Role: Test Point - Role Details: Calibration / scope probe point **Pins:** - P1 ### TP2 — [1.25mm SMD Test Point](https://www.flux.ai/jharwinbarrozo/1p25mm-smd-test-point.md) - Role Details: Calibration / scope probe point - Package: SMD_TestPoint - Role: Test Point **Pins:** - P1 ### U1 — [ACS712ELCTR-05B-T](https://www.flux.ai/vasy_skral/acs712elctr-05b-t.md) - Manufacturer Part Number: ACS712ELCTR-05B-T - Symbol Style: Parametric - Role Details: ACS712 5A hall sensor. IP pins intended to connect to off-board MAINS_L path only if ever brought to PCB (kept isolated per requirement). - Part Type: Integrated Circuit - Datasheet URL: https://www.allegromicro.com/~/media/Files/Datasheets/ACS712-Datasheet.ashx - Manufacturer Name: Allegro MicroSystems - Package: SOIC-8 - License: https://creativecommons.org/licenses/by/4.0/ - Role: Current Sensor **Pins:** - FILTER [pin 6] - GND [pin 5] - IP- [pin 4] - IP- [pin 3] - IP+ [pin 1] - IP+ [pin 2] - VCC [pin 8] - VIOUT [pin 7] ### U2 — [PCF8574DWR](https://www.flux.ai/jecstronic/pcf8574dwr.md) - Part Type: Integrated Circuit - Manufacturer Name: Texas Instruments - Role: I2C Expander - Manufacturer Part Number: PCF8574DWR - Role Details: PCF8574 I2C GPIO expander (LCD backpack core). Used here to anchor SDA/SCL and optional pullups. - Package: SOIC-16 - Datasheet URL: https://rocelec.widen.net/view/pdf/zsmwgcsqj9/scps068j.pdf?t.download=true&u=5oefqw - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - ~INT~ [pin 13] - A0 [pin 1] - A1 [pin 2] - A2 [pin 3] - P0 [pin 4] - P1 [pin 5] - P2 [pin 6] - P3 [pin 7] - P4 [pin 9] - P5 [pin 10] - P6 [pin 11] - P7 [pin 12] - SCL [pin 14] - SDA [pin 15] - VDD [pin 16] - VSS [pin 8] ### U3 — [ESP32-DEVKIT-V1](https://www.flux.ai/juan2704/esp32-devkit-v1.md) - Manufacturer Name: Espressif Systems - Role: MCU Module - Datasheet URL: https://www.espressif.com/sites/default/files/documentation/esp32_datasheet_en.pdf - Role Details: ESP32 DevKit V1 plugged into 2x 1x15 headers; used for explicit pin naming and wiring. - Manufacturer Part Number: ESP32-DEVKIT-V1 - Package: DevKitV1_30pin - Part Type: Module **Pins:** - 3V3 [pin 1] - D12 [pin 27] - D13 [pin 28] - D14 [pin 26] - D15 [pin 3] - D18 [pin 9] - D19 [pin 10] - D2 [pin 4] - D21 [pin 11] - D22 [pin 14] - D23 [pin 15] - D25 [pin 23] - D26 [pin 24] - D27 [pin 25] - D32 [pin 21] - D33 [pin 22] - D34 [pin 19] - D35 [pin 20] - D4 [pin 5] - D5 [pin 8] - EN [pin 16] - GND [pin 2] - GND__1 [pin 29] - RX0 [pin 12] - RX2 [pin 6] - TX0 [pin 13] - TX2 [pin 7] - VIN [pin 30] - VN [pin 18] - VP [pin 17] ### VR1 — [3296W-1-103LF](https://www.flux.ai/adrian95/3296w-1-103lf.md) - Datasheet URL: https://www.bourns.com/docs/product-datasheets/3296.pdf - Role: Adjust - Manufacturer Part Number: 3296W-1-103LF - Package or Case Code: 3296W1503LF - Part Type: Variable Resistor - Package: THT_Trimpot_3296W - Manufacturer Name: Bourns Inc. - Role Details: Trimpot: one for current scaling, one for LCD contrast - License: https://creativecommons.org/licenses/by/4.0/ **Pins:** - CCW [pin 1] - CW [pin 3] - WIPER [pin 2] ### VR2 — [3296W-1-103LF](https://www.flux.ai/adrian95/3296w-1-103lf.md) - Role Details: Trimpot: one for current scaling, one for LCD contrast - Manufacturer Name: Bourns Inc. - License: https://creativecommons.org/licenses/by/4.0/ - Datasheet URL: https://www.bourns.com/docs/product-datasheets/3296.pdf - Role: Adjust - Part Type: Variable Resistor - Package or Case Code: 3296W1503LF - Manufacturer Part Number: 3296W-1-103LF - Package: THT_Trimpot_3296W **Pins:** - CCW [pin 1] - CW [pin 3] - WIPER [pin 2] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/talalabuhijleh/unemployed-azure-point-of-view-gun](https://www.flux.ai/talalabuhijleh/unemployed-azure-point-of-view-gun).* --- *Generated from [https://www.flux.ai/talalabuhijleh/unemployed-azure-point-of-view-gun](https://www.flux.ai/talalabuhijleh/unemployed-azure-point-of-view-gun)*