Spark Logic

HM-10 Bluetooth Low Energy serial module connection guide

HM-10 Bluetooth Low Energy serial module Huamao HM-10 bare module wiring guide with power, signal assignments, and bench checks.

Huamao HM-10 bare module

34 contacts Current package

Jinan Huamao · 26.9 × 13 mm module with 34 castellations.

Check HM-10 transmit firmware

Required

Wire the four return pads and the crossed 3.3 V UART. Start at 9600 bit/s, 8N1, with the module unconnected to a remote device.

  • 3.3 V supply
    • VCC (12)
    • Regulated 3.3 V
    • C1.1
  • Ground
    • GND (13)
    • GND (14)
    • GND (21)
    • GND (22)
    • Supply return
    • Host ground
    • C1.2
  • Host to module
    • UART_RX (2)
    • Host UART TX
  • Module to host
    • UART_TX (1)
    • Host UART RX
C1 100 nF between 3.3 V supply and Ground3.3 V supplyC1 100 nFGround

Bench checks

  • Send uppercase AT with no CR or LF. Expect OK.
  • Query AT+BAUD? if the link works and you need to inspect the configured speed. Recheck firmware identity before using additional commands.

Jinan Huamao HM Bluetooth module datasheet V539, § 8.

Huamao HM-10 bare module wiring map

Select a contact to inspect it.

Huamao HM-10 bare module
Component-side view with the antenna at the top. Pad 1 is at upper left. The numbering passes down the left side, across the bottom and up the right side. Scroll the map to reach all contacts.
Selected pin details

21 · GND

Return · Ground

Common return. Connect every GND contact.

Jinan Huamao HM Bluetooth module datasheet V539, §§ 6.1–6.4

Electrical limits · Pin in the reference

Models and documents

This 34-pad HM-10 follows the Huamao V539 datasheet. The contact table and commands apply to the documented Huamao module and transmit firmware.

Jinan Huamao HM-10
34-pad module in the V539 pinout and land pattern.