---
title: HBOX Watchdog v3 PROD — Socket Pinouts (for silkscreen)
project: Project Drogheda
date: 2026-07-05
tags: [project-drogheda, hardware, pcb, silkscreen, pinout]
---

# Socket pinouts — for silkscreen labelling

Connected pins only (NC pins omitted). "Silk" = suggested short label that fits the
2.54 mm pitch (vertical text). Pin 1 is the **square** pad on each header.

## J1 — Blackpill (left row, pins 1→20 left to right)
| Pin | Net | Silk |
|---|---|---|
| 5 | NRST | NRST |
| 6 | BAT_SENSE | BSNS |
| 7 | PWR_CTRL | PCTL |
| 8 | GNSS_TX | G-TX |
| 9 | GNSS_RX | G-RX |
| 10 | 5V_SENSE | 5VS |
| 11 | IGN_SENSE | IGN |
| 12 | FAN_PWM | FPWM |
| 14 | EXT_LED | ELED |
| 15 | NTC_TEMP | NTC |
| 17 | FAN_TACH | FTAC |
| 18 | 3V3 | 3V3 |
| 19 | GND | GND |
| 20 | SYS5V | 5V |

## J2 — Blackpill (right row, pins 1→20)
| Pin | Net | Silk |
|---|---|---|
| 1 | BATLED1 | BL1 |
| 2 | BATLED2 | BL2 |
| 3 | BATLED3 | BL3 |
| 4 | BATLED4 | BL4 |
| 5 | CHRG_EN | CHEN |
| 6 | USART1_TX | U-TX |
| 7 | USART1_RX | U-RX |
| 11 | CHRG_STAT | CSTA |
| 12 | CHRG_FAULT | CFLT |
| 13 | BYP_CTRL | BYP |
| 14 | I2C_SCL | SCL |
| 15 | I2C_SDA | SDA |
| 18 | SYS5V | 5V |
| 19 | GND | GND |
| 20 | 3V3 | 3V3 |

## J7 — 4G XBee row 1 (pins 1→10 top to bottom)
| Pin | Net | Silk |
|---|---|---|
| 1 | 3V3_MODEM | 3V3 |
| 2 | DOUT_4G | DOUT |
| 3 | DIN_4G | DIN |
| 10 | GND | GND |

## J8 — 4G XBee row 2
All pins NC — no labels needed.

## MOD1 — simpleRTK2B Pro (Arduino headers)
| Pin | Net | Silk |
|---|---|---|
| 2 | 3V3 | 3V3 |
| 5 | SW_5V | 5V |
| 6, 7 | GND | GND |
| 15 | GNSS_RX | G-RX |
| 16 | GNSS_TX | G-TX |
| 17 | DOUT_4G | DOUT |
| 23 | USART1_RX | U-RX |
| 29 | GND | GND |

---
**Anchor labels I already staged** (power/ground, if you want to keep the placement):
J1: 3V3 / GND / 5V at pins 18-20 · J2: same at pins 18-20 · J7: 3V3 (pin 1), GND (pin 10) ·
MOD1: 3V3 (pin 2), 5V (pin 5), GND (pin 6/7). They're in my memory only — not saved — so
just re-create them from this table in KiCad.