# ESP32 Relay Automation Board ## Description 2-layer SMD-only ESP32 DevKit V1 relay automation carrier board with LM2596 module pads, ULN2803A driver, relay wire pads, LEDs, pull-downs, and no drilled holes. ## Project Details - **Owner:** hari-d-04 - **Created:** 5/11/2026 - **Last Updated:** 5/11/2026 - **Visibility:** Public ## Key Components ### CESP_BULK — [Generic Capacitor](https://www.flux.ai/jharwinbarrozo/generic-capacitor~1d.md) - Package: SMD_0603_1608Metric - Capacitance: 100uF - Package or Case Code: SMD electrolytic - Capacitor Type: Polarized - Part Type: Non-Polarized Capacitor - Role Details: Bulk capacitance local to ESP32 VIN/5V pad and GND. - Role: Bulk - Voltage Rating: 10V **Pins:** - P1 [pin 1] - P2 [pin 2] ### CESP_HF — [Generic Capacitor](https://www.flux.ai/jharwinbarrozo/generic-capacitor~1d.md) - Part Type: Non-Polarized Capacitor - Role Details: High-frequency decoupling local to ESP32 VIN/5V pad and GND. - Role: Decoupling - Capacitor Type: Ceramic - Voltage Rating: 10V - Package: SMD_0603_1608Metric - Package or Case Code: 0805 - Capacitance: 100nF **Pins:** - P1 [pin 1] - P2 [pin 2] ### D12V — [LED 0805 (2012 Metric)](https://www.flux.ai/vasyl/led-0805-2012-metric~sr7.md) - Role Details: 12V power indicator LED, driven through 2.2k resistor to GND. - Role: Indicator - Part Type: LED **Pins:** - A [pin 2] - K [pin 1] ### D5V — [LED 0805 (2012 Metric)](https://www.flux.ai/vasyl/led-0805-2012-metric~sr7.md) - Part Type: LED - Role Details: 5V power indicator LED, driven through 1k resistor to GND. - Role: Indicator **Pins:** - A [pin 2] - K [pin 1] ### DMQTT — [LED 0805 (2012 Metric)](https://www.flux.ai/vasyl/led-0805-2012-metric~sr7.md) - Part Type: LED - Role Details: MQTT status LED controlled by ESP32 GPIO4 through 1k resistor. - Role: Indicator **Pins:** - A [pin 2] - K [pin 1] ### DREL1 — [LED 0805 (2012 Metric)](https://www.flux.ai/vasyl/led-0805-2012-metric~sr7.md) - Part Type: LED - Role: Indicator - Role Details: Relay channel indicator LED connected from relay GPIO net through 1k resistor to LED to GND. **Pins:** - A [pin 2] - K [pin 1] ### DWIFI — [LED 0805 (2012 Metric)](https://www.flux.ai/vasyl/led-0805-2012-metric~sr7.md) - Part Type: LED - Role Details: WiFi status LED controlled by ESP32 GPIO2 through 1k resistor. - Role: Indicator **Pins:** - A [pin 2] - K [pin 1] ### ESP_L1_EN — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role Details: ESP32 DevKit V1 L1 EN pad; target pad 2.5mm x 3.5mm, 2.54mm pitch, no drilled hole. - Role: SMD Module Pad **Pins:** - P1 ### ESP_L10_GPIO27 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 L10 GPIO27 pad; target pad 2.5mm x 3.5mm, no hole. - Testpoint Size: 0.5 **Pins:** - P1 ### ESP_L11_GPIO14 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: ESP32 DevKit V1 L11 GPIO14 relay 2 control pad; target pad 2.5mm x 3.5mm, no hole. - Testpoint Size: 0.5 - Role: SMD Module Pad **Pins:** - P1 ### ESP_L12_GPIO12 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 L12 GPIO12 pad; target pad 2.5mm x 3.5mm, no hole. - Testpoint Size: 0.5 **Pins:** - P1 ### ESP_L13_GND — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 L13 GND pad; target pad 2.5mm x 3.5mm, no hole. **Pins:** - P1 ### ESP_L14_GPIO13 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 L14 GPIO13 relay 1 control pad; target pad 2.5mm x 3.5mm, no hole. **Pins:** - P1 ### ESP_L15_VIN5V — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 L15 VIN/5V pad; target pad 2.5mm x 3.5mm, no hole. **Pins:** - P1 ### ESP_L2_GPIO36 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 L2 GPIO36 pad; target pad 2.5mm x 3.5mm, no hole. **Pins:** - P1 ### ESP_L3_GPIO39 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 L3 GPIO39 pad; target pad 2.5mm x 3.5mm, no hole. **Pins:** - P1 ### ESP_L4_GPIO34 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 L4 GPIO34 pad; target pad 2.5mm x 3.5mm, no hole. **Pins:** - P1 ### ESP_L5_GPIO35 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role Details: ESP32 DevKit V1 L5 GPIO35 pad; target pad 2.5mm x 3.5mm, no hole. - Role: SMD Module Pad **Pins:** - P1 ### ESP_L6_GPIO32 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: ESP32 DevKit V1 L6 GPIO32 pad; target pad 2.5mm x 3.5mm, no hole. - Testpoint Size: 0.5 - Role: SMD Module Pad **Pins:** - P1 ### ESP_L7_GPIO33 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: ESP32 DevKit V1 L7 GPIO33 pad; target pad 2.5mm x 3.5mm, no hole. - Role: SMD Module Pad - Testpoint Size: 0.5 **Pins:** - P1 ### ESP_L8_GPIO25 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 L8 GPIO25 relay 8 control pad; target pad 2.5mm x 3.5mm, no hole. - Testpoint Size: 0.5 **Pins:** - P1 ### ESP_L9_GPIO26 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 L9 GPIO26 pad; target pad 2.5mm x 3.5mm, no hole. - Testpoint Size: 0.5 **Pins:** - P1 ### ESP_R1_GPIO23 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 R1 GPIO23 relay 7 control pad; target pad 2.5mm x 3.5mm, no hole. - Testpoint Size: 0.5 **Pins:** - P1 ### ESP_R10_GPIO17 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 R10 GPIO17 relay 4 control pad; target pad 2.5mm x 3.5mm, no hole. - Testpoint Size: 0.5 **Pins:** - P1 ### ESP_R11_GPIO16 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Module Pad - Testpoint Size: 0.5 - Role Details: ESP32 DevKit V1 R11 GPIO16 relay 3 control pad; target pad 2.5mm x 3.5mm, no hole. **Pins:** - P1 ### ESP_R12_GPIO4 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: ESP32 DevKit V1 R12 GPIO4 MQTT LED pad; target pad 2.5mm x 3.5mm, no hole. - Testpoint Size: 0.5 - Role: SMD Module Pad **Pins:** - P1 ### ESP_R13_GPIO0 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role Details: ESP32 DevKit V1 R13 GPIO0 pad; target pad 2.5mm x 3.5mm, no hole. - Role: SMD Module Pad **Pins:** - P1 ### ESP_R14_GPIO2 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 R14 GPIO2 WiFi LED pad; target pad 2.5mm x 3.5mm, no hole. - Testpoint Size: 0.5 **Pins:** - P1 ### ESP_R15_3V3 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 R15 3V3 pad; target pad 2.5mm x 3.5mm, no hole. - Testpoint Size: 0.5 **Pins:** - P1 ### ESP_R2_GPIO22 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 R2 GPIO22 pad; target pad 2.5mm x 3.5mm, no hole. **Pins:** - P1 ### ESP_R3_TX0_GPIO1 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Module Pad - Role Details: ESP32 DevKit V1 R3 TX0/GPIO1 pad; target pad 2.5mm x 3.5mm, no hole. - Testpoint Size: 0.5 **Pins:** - P1 ### ESP_R4_RX0_GPIO3 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: ESP32 DevKit V1 R4 RX0/GPIO3 pad; target pad 2.5mm x 3.5mm, no hole. - Role: SMD Module Pad - Testpoint Size: 0.5 **Pins:** - P1 ### ESP_R5_GPIO21 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: ESP32 DevKit V1 R5 GPIO21 pad; target pad 2.5mm x 3.5mm, no hole. - Role: SMD Module Pad - Testpoint Size: 0.5 **Pins:** - P1 ### ESP_R6_GND — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: ESP32 DevKit V1 R6 GND pad; target pad 2.5mm x 3.5mm, no hole. - Testpoint Size: 0.5 - Role: SMD Module Pad **Pins:** - P1 ### ESP_R7_GPIO19 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: ESP32 DevKit V1 R7 GPIO19 relay 6 control pad; target pad 2.5mm x 3.5mm, no hole. - Testpoint Size: 0.5 - Role: SMD Module Pad **Pins:** - P1 ### ESP_R8_GPIO18 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Module Pad - Testpoint Size: 0.5 - Role Details: ESP32 DevKit V1 R8 GPIO18 relay 5 control pad; target pad 2.5mm x 3.5mm, no hole. **Pins:** - P1 ### ESP_R9_GPIO5 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: ESP32 DevKit V1 R9 GPIO5 pad; target pad 2.5mm x 3.5mm, no hole. - Role: SMD Module Pad - Testpoint Size: 0.5 **Pins:** - P1 ### LED1 — [LED 0805 (2012 Metric)](https://www.flux.ai/vasyl/led-0805-2012-metric~sr7.md) - Role Details: Relay channel indicator LED connected from relay GPIO net through 1k resistor to LED to GND. - Part Type: LED - Role: Indicator **Pins:** - A [pin 2] - K [pin 1] ### LED2 — [LED 0805 (2012 Metric)](https://www.flux.ai/vasyl/led-0805-2012-metric~sr7.md) - Role Details: Relay channel indicator LED connected from relay GPIO net through 1k resistor to LED to GND. - Part Type: LED - Role: Indicator **Pins:** - A [pin 2] - K [pin 1] ### LED3 — [LED 0805 (2012 Metric)](https://www.flux.ai/vasyl/led-0805-2012-metric~sr7.md) - Role: Indicator - Role Details: Relay channel indicator LED connected from relay GPIO net through 1k resistor to LED to GND. - Part Type: LED **Pins:** - A [pin 2] - K [pin 1] ### LED4 — [LED 0805 (2012 Metric)](https://www.flux.ai/vasyl/led-0805-2012-metric~sr7.md) - Part Type: LED - Role: Indicator - Role Details: Relay channel indicator LED connected from relay GPIO net through 1k resistor to LED to GND. **Pins:** - A [pin 2] - K [pin 1] ### LED5 — [LED 0805 (2012 Metric)](https://www.flux.ai/vasyl/led-0805-2012-metric~sr7.md) - Part Type: LED - Role Details: Relay channel indicator LED connected from relay GPIO net through 1k resistor to LED to GND. - Role: Indicator **Pins:** - A [pin 2] - K [pin 1] ### LED6 — [LED 0805 (2012 Metric)](https://www.flux.ai/vasyl/led-0805-2012-metric~sr7.md) - Role Details: Relay channel indicator LED connected from relay GPIO net through 1k resistor to LED to GND. - Part Type: LED - Role: Indicator **Pins:** - A [pin 2] - K [pin 1] ### LED7 — [LED 0805 (2012 Metric)](https://www.flux.ai/vasyl/led-0805-2012-metric~sr7.md) - Part Type: LED - Role: Indicator - Role Details: Relay channel indicator LED connected from relay GPIO net through 1k resistor to LED to GND. **Pins:** - A [pin 2] - K [pin 1] ### LM_INM — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: LM2596 module LM_IN- pad; target pad 5mm x 5mm, no drilled hole. - Testpoint Size: 0.5 - Role: SMD Module Pad **Pins:** - P1 ### LM_INP — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: LM2596 module LM_IN+ pad; target pad 5mm x 5mm, no drilled hole. - Testpoint Size: 0.5 - Role: SMD Module Pad **Pins:** - P1 ### LM_OUTM — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role Details: LM2596 module LM_OUT- pad; target pad 5mm x 5mm, no drilled hole. - Role: SMD Module Pad **Pins:** - P1 ### LM_OUTP — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role Details: LM2596 module LM_OUT+ 5V pad; target pad 5mm x 5mm, no drilled hole. - Role: SMD Module Pad **Pins:** - P1 ### RELAY_12V — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role: SMD Wire Pad - Role Details: Relay module 12V solder wire pad; target pad 6mm x 6mm, no drilled hole. **Pins:** - P1 ### RELAY_GND — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: Relay module GND solder wire pad; target pad 6mm x 6mm, no drilled hole. - Testpoint Size: 0.5 - Role: SMD Wire Pad **Pins:** - P1 ### RLED1 — [Generic Resistor](https://www.flux.ai/jharwinbarrozo/generic-resistor~3e.md) - Package or Case Code: 0805 - Part Type: Resistor - Resistance: 1kΩ - Package: SMD_0603_1608Metric - Role Details: 1k resistor from each relay GPIO control net to its relay indicator LED. - Role: LED Current Limit **Pins:** - P1 [pin 1] - P2 [pin 2] ### RLY_IN1 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role Details: Relay input 1 solder wire pad; target pad 3mm x 4mm, no drilled hole. - Role: SMD Wire Pad **Pins:** - P1 ### RLY_IN2 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Wire Pad - Role Details: Relay input 2 solder wire pad; target pad 3mm x 4mm, no drilled hole. - Testpoint Size: 0.5 **Pins:** - P1 ### RLY_IN3 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Wire Pad - Testpoint Size: 0.5 - Role Details: Relay input 3 solder wire pad; target pad 3mm x 4mm, no drilled hole. **Pins:** - P1 ### RLY_IN4 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: Relay input 4 solder wire pad; target pad 3mm x 4mm, no drilled hole. - Role: SMD Wire Pad - Testpoint Size: 0.5 **Pins:** - P1 ### RLY_IN5 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Wire Pad - Role Details: Relay input 5 solder wire pad; target pad 3mm x 4mm, no drilled hole. - Testpoint Size: 0.5 **Pins:** - P1 ### RLY_IN6 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role: SMD Wire Pad - Testpoint Size: 0.5 - Role Details: Relay input 6 solder wire pad; target pad 3mm x 4mm, no drilled hole. **Pins:** - P1 ### RLY_IN7 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Testpoint Size: 0.5 - Role Details: Relay input 7 solder wire pad; target pad 3mm x 4mm, no drilled hole. - Role: SMD Wire Pad **Pins:** - P1 ### RLY_IN8 — [Generic Testpoint](https://www.flux.ai/jharwinbarrozo/generic-testpoint~esx.md) - Role Details: Relay input 8 solder wire pad; target pad 3mm x 4mm, no drilled hole. - Testpoint Size: 0.5 - Role: SMD Wire Pad **Pins:** - P1 ### RMQTT_LED — [Generic Resistor](https://www.flux.ai/jharwinbarrozo/generic-resistor~3e.md) - Package: SMD_0603_1608Metric - Resistance: 1kΩ - Role: LED Current Limit - Part Type: Resistor - Package or Case Code: 0805 - Role Details: 1k resistor from GPIO4 to MQTT status LED. **Pins:** - P1 [pin 1] - P2 [pin 2] ### RPD1 — [Generic Resistor](https://www.flux.ai/jharwinbarrozo/generic-resistor~3e.md) - Package: SMD_0603_1608Metric - Resistance: 100kΩ - Role Details: 100k pull-down from relay GPIO control net to GND to keep relay driver input low during boot/reset. - Package or Case Code: 0805 - Role: Pull Up/Down - Part Type: Resistor **Pins:** - P1 [pin 1] - P2 [pin 2] ### RWIFI_LED — [Generic Resistor](https://www.flux.ai/jharwinbarrozo/generic-resistor~3e.md) - Part Type: Resistor - Package or Case Code: 0805 - Role Details: 1k resistor from GPIO2 to WiFi status LED. - Resistance: 1kΩ - Package: SMD_0603_1608Metric - Role: LED Current Limit **Pins:** - P1 [pin 1] - P2 [pin 2] ### U1 — [ULN2803A](https://www.flux.ai/lcsc/uln2803a~i9jk.md) - Package or Case Code: SOP-18_L11.4-W7.6-P1.27-LS10.6-BL - Role: Relay Driver - Part Type: Darlington transistor array driver - LCSC Part Number: C845537 - JLCPCB Part Class: Extended Part - Manufacturer Part Number: ULN2803A - Role Details: ULN2803A SOP-18; GPIO inputs IN1-IN8, open-collector outputs OUT1-OUT8 to relay module input pads; COM intentionally NC; GND to board GND. - Manufacturer Name: UMW(友台半导体) - Datasheet URL: https://storage.googleapis.com/graviton-electric-symbols/document_assets/lcsc/2410251531_UMW-Youtai-Semiconductor-Co---Ltd--ULN2803A_C845537.pdf - Product Info Url: https://lcsc.com/product-detail/Darlington-transistor-array-driver_UMW-Youtai-Semiconductor-Co-Ltd-ULN2803A_C845537.html **Pins:** - COM [pin 10] - GND [pin 9] - Input [pin 5] - Input [pin 1] - Input [pin 6] - Input [pin 4] - Input [pin 8] - Input [pin 3] - Input [pin 2] - Input [pin 7] - Output [pin 16] - Output [pin 15] - Output [pin 13] - Output [pin 12] - Output [pin 18] - Output [pin 17] - Output [pin 11] - Output [pin 14] *The full schematic, PCB layout, bill of materials, and interactive design are available at [https://www.flux.ai/hari-d-04/esp32-relay-automation-board~et](https://www.flux.ai/hari-d-04/esp32-relay-automation-board~et).* --- *Generated from [https://www.flux.ai/hari-d-04/esp32-relay-automation-board~et](https://www.flux.ai/hari-d-04/esp32-relay-automation-board~et)*