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Pin headers and JST connectors

2.54 mm headers for breadboard-style wiring, and small JST connectors (SH 1.0 mm for Qwiic/STEMMA QT I²C, PH 2.0 mm for batteries) for cables.

Pin headers#

The 2.54 mm (0.1") header is the universal connector: breadboards, jumper wires, modules. Male pins on one board, a female socket on the other. Through-hole, cheap, robust. In PCB Canvas every 1×N connector uses the Conn_01xNN symbol; the footprint decides header, socket or JST.

Qwiic / STEMMA QT#

SparkFun’s Qwiic and Adafruit’s STEMMA QT are the same thing: a JST SH 4-pin, 1.0 mm connector carrying I²C at 3.3 V. Pin order: 1 GND, 2 3V3, 3 SDA, 4 SCL. Chain sensors with ready-made cables, no soldering.

Example circuit: The same I²C bus on a Qwiic connector (J1) and a 2.54 mm header (J2), with one pair of pull-ups for the bus.
The same I²C bus on a Qwiic connector (J1) and a 2.54 mm header (J2), with one pair of pull-ups for the bus. Open the qwiic_connector example from this page in PCB Canvas: “Insert into my schematic”.

JST PH (batteries)#

2.0 mm, 2-pin: the LiPo battery plug. See LiPo charger for the polarity trap.

Pitfalls#

  • Pin 1 is marked by a square pad and a silkscreen mark; label the signals on the silkscreen too.
  • JST SH mounting tabs are pads without a pin in the symbol; the ERC notes one unconnected pad, which is fine (solder them for strength).
  • Qwiic is 3.3 V only. Do not put 5 V on it.

Footprint#

Headers are through-hole and hand-soldered. JST SH 4-pin horizontal (C160404) is a JLCPCB extended part.