Connectors and Wiring

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Revision as of 14:32, 13 September 2010 by Aerovista (talk | contribs) (→‎Crimpers)
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Molex PicoBlade™ 1.25mm (.049") Pitch Connector System

Molex plug

Paparazzi autopilots use 1.25mm Molex PicoBlade™ headers for all connections. Users must make their own wiring harnesses by either crimping the molex terminal pins onto their wiring or soldering pre-crimped wires to their peripherals.

  • Be sure to order plenty of 1.25mm Molex plugs (female)
  • Current: 1.0A
  • Wires are available (post sources) with pins already crimped - simply trim and solder these to your peripherals and assemble them into the Molex plugs. Try Farnell Part number 112-5276 or 112-5274, RS-Components 279-9516 or 279-9544. In the US Newark has them. Part number 93K4876 ~$10 for 10 300mm wires with a socket on each end.

1.25mm (0.049") Pitch PicoBlade Receptacle (Female)

These are the connector housings, used in the wiring harness and not the PCB

  • 51021-0200 1.25mm Molex PicoBlade Receptacle 2pos
  • 51021-0300 1.25mm Molex PicoBlade Receptacle 3pos
  • 51021-0400 1.25mm Molex PicoBlade Receptacle 4pos
  • 51021-0500 1.25mm Molex PicoBlade Receptacle 5pos
  • 51021-0700 1.25mm Molex PicoBlade Receptacle 7pos
  • 51021-0800 1.25mm Molex PicoBlade Receptacle 8pos
  • 51021-1000 1.25mm Molex PicoBlade Receptacle 10pos

1.25mm (0.049") Female Crimp Terminals

The 1.25mm terminals are extremely small and cannot and should not be soldered, crimped with pliers, or attached by any tool other than the genuine Molex crimper. Remember that if a wire comes loose, any wire, the plane will crash!

  • 50058-8000 28-32 tape ($0.04-0.07 USD based on qty)
  • 50079-8000 26-28 tape ($0.03-0.07 USD based on qty)
Molex pin

Crimpers

Molex Crimper

Crimpers are available from Mouser or Digi-Key for approximately $200 USD and will prove worthwhile for most users. The fact that Wire-to-Wire Plugs are available should make this Crimper an even more worthwhile investment.

  • Strip Length should be between 1.40 to 1.90mm
  • Wire Insulation Range should be < 1.0mm with the 28-32AWG Terminals and < 1.04mm with the 26-28AWG Terminals

1.25mm (0.049") Pitch PicoBlade Plug (Male, Wire-to-wire)

These Plugs are for Wire-to-Wire connections and they are not required. Their reference here is for convenience only.

1.25mm (0.049") Male Crimp Terminals

These Crimp Terminals are for Wire-to-Wire connections and they are not required. Their reference here is for convenience only.


Power Supply

For reference, Matthew Currie is assembling his Tiny(s) with WS Deans Micro 2R connectors for power as they are a commonly available R/C connector and are of high quality and durability. They do not have a positive lock mechanism but insert under a lot of pressure. They do not require any special crimping tools and withstand up to 15A.

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Wiring

Wiring is a critical part of any autonomous vehicle and the importance of high quality reliable wiring cannot be stressed enough. The molex connectors work best with 0.4mm (26AWG) wire though can also be used with 0.3mm (29AWG) on extremely lightweight models. Larger sizes will not fit. High strand-count wire is strongly advised as it is much less prone to failure from fatigue. The insulation type is critical: silicone is extremely flexible and heat resistant but easily cut or torn, teflon is extremely heat and abrasion resistant but not very flexible. Either choice is good though teflon is more durable and readily available. Standard plastic/vinyl insulated wire does not solder well (insulation melts) and does not crimp well - the vinyl insulation provides little or no strength and wires tend to break at the solder or crimp joints. Some recommended wire sources are:

  • Alpha 19 strand Teflon insulated 26AWG wire: Mouser P/N: 2843/19
  • RDS Wire sells very high strand count (66 strands!) 26AWG and 29AWG silicone wire for around $0.60 to $1 per foot in quantity but they mostly deal with very large production orders and may or may not have small quantites available for a reasonable price. Call them for details.
  • Hobby-Lobby has a great selection of larger silicone wire at great prices but this wire is only useful for motors and batteries. The 0.5mm wire they offer has very thick silicone insulation and will not fit into the molex connectors.
  • A convenient female USB mini-B receptacle ( Mouser P/N: 500075-0517) permits soldering directly without a PCB