Date: Thu, 1 Sep 1994 15:35:49 -0400
Message-Id: <9409011932.AA18091@pepper.Eng.Sun.COM>
Errors-To: gkulosa@oberon.com
Reply-To: cmcmanis@scndprsn.FirstPerson.COM
Originator: robot-board@oberon.com
Sender: gkulosa@oberon.com
Precedence: bulk
From: cmcmanis@scndprsn.FirstPerson.COM (Chuck McManis)
To: Multiple recipients of list <robot-board@oberon.com>
Subject: Cool miniboard Connectors


{Copy of my post to comp.robotics}
I have 8 miniboards, and because of this, have built *many* miniboard
type connectors for sensors and motors. I thought I'd pass on some 
information on some cool miniboard compatible connectors.

If you have a miniboard or have read the documentation for the miniboard
you will recall Fred Martin's excellent exposition on how to construct
connectors that plug into the miniboard's connector headers. Basically
the sequence is this:
	a) Cut off a set of either 3 or 4 pins from a male connector header
	
	b) remove pin 2. 

	c) remove the 'nubs' along the sides of the pins

	d) solder wires to the pins you need

	e) put a drop of hot glue on as a strain relief.

	f) put some heat shrink tubing around the assembly.

This is easily the most cost effective way to make connectors because
the header strips price out to about $0.16 per connector. With hot glue
and heat shrink tubing your probably still under $0.25. 

Now, in my opinion, the resulting connectors don't look "professional" (how
can anything with hot glue blobbed on it look pro :-)) and it is an art
to getting them just right so that they don't interfere with neighboring
connectors.

An alternative is the Berg Microlatch connector. These are pin and housing
connectors like standard "molex" connectors and are much more expensive but
may be more robust in the long term. These connectors consist of crimp
pins and a plastic housing. You crimp and then solder your wires to the 
pins, then insert them into the housing and then you're done.

Newark Electronics sells them and these are the part numbers:

Newark		Berg
part #		part #		Description			cost
--------	-------		------------------------	----
89F4597		65039-034	3 slot housing (motors)		.65
89F4596 	65039-033	4 slot housing (sensors)	.71
89F4586 	48116-000	Male crimp pins			.83 (each!)

As it turns out you can only get the _gold_ male pins from Newark, the
tin pins are less expensive but I haven't found a supplier for them
yet. And Newark doesn't seem to offer a volume discount on the male
pins.

So a an active sensor connector (3 pins, housing)	 $3.20 
A passive sensor connector (2 pins, housing)		 $2.37
A motor connector (2 pins, housing)			 $2.31
Enough to fill all connectors (24 sensors + 4 motors)	$86.04

Also Newark sells a crimp tool for $654 (which I can't believe _anyone_
buys these) but you can crimp them yourself with a pair of needle
nose pliers fairly easily.

Clearly its a lot more money, but the resulting connectors would seem
to be a bit more reliable than the hand built ones. They also look better
and always fit next to each other on your board. Remember though that 
appearance is always in the eye of the beholder.


--Chuck