# ZAPP-LB-V1 Smart Relay Logic Board ## Description 2-layer SELV ESP8266 smart relay logic board using an ESP-12F module, MCP1700-3302E 5V-to-3.3V LDO, exact 2x7 relay/control connector pinout, 4-pin UART programming header, GPIO0 flash test point, active-low GPIO2 status LED, power and GPIO test points, 55x45 mm board outline, top-side assembly, bottom solid ground pour, ESP-12F antenna keepout, 4 M3 mounting holes, and silkscreen connector labels for production use. ## Project Details - **Owner:** cookiea11 - **Created:** 4/14/2026 - **Last Updated:** 4/14/2026 - **Visibility:** Public ## Key Components ### D1 — [LED 0603 (1608 Metric)](https://www.flux.ai/jharwinbarrozo/generic-led-0603-1608-metric~yk.md) - Role: Status Indicator - Part Type: LED - Role Details: Active-low status LED on GPIO2 - Package: 0603 - Manufacturer Part Number: LED 0603 (1608 Metric) **Pins:** - A [pin 2] - K [pin 1] ### H1 — [M3 Mounting Hole](https://www.flux.ai/vasyl/m3-mounting-hole~kc3.md) - Role Details: M3 corner mounting hole - Manufacturer Name: Wurth Elektronik - Role: Mounting Hole - Manufacturer Part Number: 9774035243R - Product Info Url: https://www.mcmaster.com/screws/drive-style~torx/rounded-head-style~pan/material~steel/specifications-met~iso-7045/thread-size~m3/finish~zinc-plated/ - Package: M3 **Pins:** - terminal ### H2 — [M3 Mounting Hole](https://www.flux.ai/vasyl/m3-mounting-hole~kc3.md) - Manufacturer Part Number: 9774035243R - Manufacturer Name: Wurth Elektronik - Package: M3 - Role Details: M3 corner mounting hole - Product Info Url: https://www.mcmaster.com/screws/drive-style~torx/rounded-head-style~pan/material~steel/specifications-met~iso-7045/thread-size~m3/finish~zinc-plated/ - Role: Mounting Hole **Pins:** - terminal ### H3 — [M3 Mounting Hole](https://www.flux.ai/vasyl/m3-mounting-hole~kc3.md) - Role Details: M3 corner mounting hole - Package: M3 - Manufacturer Name: Wurth Elektronik - Manufacturer Part Number: 9774035243R - Role: Mounting Hole - Product Info Url: https://www.mcmaster.com/screws/drive-style~torx/rounded-head-style~pan/material~steel/specifications-met~iso-7045/thread-size~m3/finish~zinc-plated/ **Pins:** - terminal ### H4 — [M3 Mounting Hole](https://www.flux.ai/vasyl/m3-mounting-hole~kc3.md) - Role: Mounting Hole - Package: M3 - Role Details: M3 corner mounting hole - Product Info Url: https://www.mcmaster.com/screws/drive-style~torx/rounded-head-style~pan/material~steel/specifications-met~iso-7045/thread-size~m3/finish~zinc-plated/ - Manufacturer Part Number: 9774035243R - Manufacturer Name: Wurth Elektronik **Pins:** - terminal ### P1 — [Pin Header 02x07 2.54mm Vertical](https://www.flux.ai/adrian95/pin-header-02x07-254mm-vertical~bnn.md) - Package: THT 2x07 2.54mm - Manufacturer Part Number: Pin Header 02x07 2.54mm Vertical - Part Type: Connector - Role: External Interface Connector - Role Details: Carries 5V, ground, relay controls, switch sense lines, UART debug, and reserved auxiliary I2C pins - License: https://creativecommons.org/licenses/by/4.0/ **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_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] ### P2 — [Pin Header 01x04 2.54mm Vertical](https://www.flux.ai/adrian95/pin-header-01x04-254mm-vertical~l97.md) - Part Type: Connector - License: https://creativecommons.org/licenses/by/4.0/ - Role Details: Provides 3.3V, GND, U0TXD, and U0RXD for programming and console access - Manufacturer Part Number: Pin Header 01x04 2.54mm Vertical - Package: THT 1x04 2.54mm - Role: Programming Header **Pins:** - Pin_1 [pin 1] - Pin_2 [pin 2] - Pin_3 [pin 3] - Pin_4 [pin 4] ### TP1 — [1.25mm SMD Test Point](https://www.flux.ai/jharwinbarrozo/1p25mm-smd-test-point~b9.md) - Role: Test Point - Role Details: 5V input rail access - Manufacturer Name: Keystone Electronics - Package: SMD Test Point - Manufacturer Part Number: 5016 **Pins:** - P1 ### TP10 — [1.25mm SMD Test Point](https://www.flux.ai/jharwinbarrozo/1p25mm-smd-test-point~b9.md) - Manufacturer Part Number: 5016 - Manufacturer Name: Keystone Electronics - Role: Test Point - Role Details: GPIO16 switch sense access - Package: SMD Test Point **Pins:** - P1 ### TP11 — [1.25mm SMD Test Point](https://www.flux.ai/jharwinbarrozo/1p25mm-smd-test-point~b9.md) - Role Details: GPIO9 switch sense access - Manufacturer Name: Keystone Electronics - Manufacturer Part Number: 5016 - Package: SMD Test Point - Role: Test Point **Pins:** - P1 ### TP12 — [1.25mm SMD Test Point](https://www.flux.ai/jharwinbarrozo/1p25mm-smd-test-point~b9.md) - Package: SMD Test Point - Manufacturer Part Number: 5016 - Role Details: GPIO10 switch sense access - Manufacturer Name: Keystone Electronics - Role: Test Point **Pins:** - P1 ### TP2 — [1.25mm SMD Test Point](https://www.flux.ai/jharwinbarrozo/1p25mm-smd-test-point~b9.md) - Manufacturer Part Number: 5016 - Role Details: 3.3V rail access - Package: SMD Test Point - Role: Test Point - Manufacturer Name: Keystone Electronics **Pins:** - P1 ### TP3 — [1.25mm SMD Test Point](https://www.flux.ai/jharwinbarrozo/1p25mm-smd-test-point~b9.md) - Package: SMD Test Point - Role Details: Ground access - Manufacturer Part Number: 5016 - Manufacturer Name: Keystone Electronics - Role: Test Point **Pins:** - P1 ### TP4 — [1.25mm SMD Test Point](https://www.flux.ai/jharwinbarrozo/1p25mm-smd-test-point~b9.md) - Manufacturer Name: Keystone Electronics - Package: SMD Test Point - Manufacturer Part Number: 5016 - Role Details: GPIO0 boot mode access - Role: Test Point **Pins:** - P1 ### TP5 — [1.25mm SMD Test Point](https://www.flux.ai/jharwinbarrozo/1p25mm-smd-test-point~b9.md) - Manufacturer Name: Keystone Electronics - Package: SMD Test Point - Manufacturer Part Number: 5016 - Role Details: GPIO4 relay control access - Role: Test Point **Pins:** - P1 ### TP6 — [1.25mm SMD Test Point](https://www.flux.ai/jharwinbarrozo/1p25mm-smd-test-point~b9.md) - Role: Test Point - Role Details: GPIO5 relay control access - Manufacturer Part Number: 5016 - Manufacturer Name: Keystone Electronics - Package: SMD Test Point **Pins:** - P1 ### TP7 — [1.25mm SMD Test Point](https://www.flux.ai/jharwinbarrozo/1p25mm-smd-test-point~b9.md) - Manufacturer Name: Keystone Electronics - Role Details: GPIO12 relay control access - Manufacturer Part Number: 5016 - Package: SMD Test Point - Role: Test Point **Pins:** - P1 ### TP8 — [1.25mm SMD Test Point](https://www.flux.ai/jharwinbarrozo/1p25mm-smd-test-point~b9.md) - Package: SMD Test Point - Role Details: GPIO13 relay control access - Manufacturer Part Number: 5016 - Role: Test Point - Manufacturer Name: Keystone Electronics **Pins:** - P1 ### TP9 — [1.25mm SMD Test Point](https://www.flux.ai/jharwinbarrozo/1p25mm-smd-test-point~b9.md) - Role: Test Point - Manufacturer Part Number: 5016 - Role Details: GPIO14 switch sense access - Manufacturer Name: Keystone Electronics - Package: SMD Test Point **Pins:** - P1 ### U1 — [ESP-12F](https://www.flux.ai/adrian95/esp-12f~1h1.md) - Datasheet URL: https://media.digikey.com/pdf/Data%20Sheets/Adafruit%20PDFs/2491_Web.pdf - Role Details: ESP8266 WiFi module with integrated PCB antenna, relay control GPIOs, UART programming, and status indication - Implementation Details: Pins ADC, CS0, MISO, MOSI, and SCLK are intentionally unused in this design and should be treated as NC per design intent. - Pin Type: Not Connected - License: https://creativecommons.org/licenses/by/4.0/ - Part Type: Module - Manufacturer Name: AI-Thinker - Role: Main Controller - Manufacturer Part Number: ESP-12F - Package: ESP-12F **Pins:** - ADC [pin 2] - CS0 [pin 9] - EN [pin 3] - GND [pin 15] - GPIO0 [pin 18] - GPIO10 [pin 12] - GPIO12 [pin 6] - GPIO13 [pin 7] - GPIO14 [pin 5] - GPIO15 [pin 16] - GPIO16 [pin 4] - GPIO2 [pin 17] - GPIO4 [pin 19] - GPIO5 [pin 20] - GPIO9 [pin 11] - MISO [pin 10] - MOSI [pin 13] - RST [pin 1] - RXD0 [pin 21] - SCLK [pin 14] - TXD0 [pin 22] - VCC [pin 8] ### U2 — [MCP1700T-3302E-TT](https://www.flux.ai/adrian95/mcp1700t-3302e-tt~h60.md) - Role Details: 3.3V LDO from 5V input; exact MCP1700 family implementation for the logic rail - Package: SOT-23 - Manufacturer Name: Microchip Technology - Datasheet URL: https://datasheet.octopart.com/MCP1700T-3302E/TT-Microchip-datasheet-532260.pdf - Role: Voltage Regulator - Part Type: Integrated Circuit - License: https://creativecommons.org/licenses/by/4.0/ - Manufacturer Part Number: MCP1700T-3302E/TT **Pins:** - GND [pin 1] - VI [pin 3] - VO [pin 2] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/cookiea11/zapp-lb-v1-smart-relay-logic-board~z6](https://www.flux.ai/cookiea11/zapp-lb-v1-smart-relay-logic-board~z6).* --- *Generated from [https://www.flux.ai/cookiea11/zapp-lb-v1-smart-relay-logic-board~z6](https://www.flux.ai/cookiea11/zapp-lb-v1-smart-relay-logic-board~z6)*