<div dir="ltr">Pete,<div><br></div><div>What Charlie is trying to do is create a board that the people working on the CANInstall spec can use as a base line tool. We won't be using long cables for this initial work.</div><div><br></div><div>I like the RJ11 for some things, but it needs to mate with a flat cable which by its nature can't be twisted, CAT cables won't mate to it without a lot of extra work. We need, as Charlie just told me, four wires, two for the CAN protocol and two for power. Each one will go to some sort of sensor.</div><div><br></div><div>~Carl</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Fri, Sep 25, 2015 at 12:46 PM, Pete Soper via TriEmbed <span dir="ltr"><<a href="mailto:triembed@triembed.org" target="_blank">triembed@triembed.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000">
The cable requirement for CANBUS is explicitly dictated by the bus
standard (covered in this <a href="http://www.ti.com/lit/an/slla270/slla270.pdf" target="_blank">TI blurb</a>):
you'll be using 120 ohm twisted pair. Accommodating the 120 ohm
termination resistors needed at the two ends of the bus is a side
issue that might interact with connector choice. The easy choice for
cable is UTP (aka CAT3/5/6) with as few twisted pairs as you can get
by with (since canbus only uses one pair). Somebody recently gave
away hundreds of feet of this stuff at a TriEmbed meeting, so I
think this is a good choice.<br>
<br>
The bus is only two wires, plus one more for an optional shield. So
a very simple connector will do it. IMO the lowly RJ11 will get the
job done. I have three crimping tools you can borrow. :-) The male
connectors are cheap as dirt. Here's a <a href="http://www.digikey.com/product-detail/en/A-2014-0-4-R/AE10390-ND/2183641" target="_blank">Digikey
jack</a> (35 cents at Q50). Some of the "big boys" use RJ45, but I
can't see the need for that and it's just extra cost wrt PCB area.<br>
<br>
The lowly RJ11 combined with UTP cable might be a practical
solution. The connector is "keyed", trivial to get in and out, but
stays in place. You could also arrange a convention where a
termination resistor could either be crimped into two additional
connector sites (so the termination is part of the cable) or handled
on the PCB. A weather boot would be used for cases where crud might
get inside the connector, as it is highly exposed. Using dielectric
grease to exclude oxygen would be a good idea too for cases where
the connection is going to be exposed.<br>
<br>
-Pete<div><div class="h5"><br>
<br>
<div>On 09/25/2015 10:18 AM, Charles West
via TriEmbed wrote:<br>
</div>
</div></div><blockquote type="cite"><div><div class="h5">
<div dir="ltr">
<div>
<div>
<div>
<div>Hello,<br>
<br>
</div>
I'm working on a board for the CanInstall autoregistration
project and I'm not really sure what connectors to use for
it. I'm currently leaning toward either DF13-4 connectors
or simple 4 pin headers. If I may ask, are there any
other connectors that you would recommend or have used in
your projects?<br>
<br>
</div>
Pros/cons:<br>
DF13:<br>
The upside is that they are very small, connect very
securely and SMD female connectors are $.41 per. The
downside is that they are extremely hard to get out (don't
pull on cable, very gently pry with finger nail on one side,
then the other) and cables for them are extremely hard to
find/expensive ($1.5 per in lots of 20 is the cheapest I've
found).<br>
<br>
Vertical Headers:<br>
The plus is I can get break apart SMD headers at roughly
$.05 each including shipping at lots of $5 (<a href="http://www.ebay.com/itm/10pcs-2-54MM-1-40Pin-SMD-SMT-1-40Pin-Male-Single-Row-Pin-Header-/261879748701?hash=item3cf93fd85d" target="_blank"></a><a href="http://www.ebay.com/itm/10pcs-2-54MM-1-40Pin-SMD-SMT-1-40Pin-Male-Single-Row-Pin-Header-/261879748701?hash=item3cf93fd85d" target="_blank">http://www.ebay.com/itm/10pcs-2-54MM-1-40Pin-SMD-SMT-1-40Pin-Male-Single-Row-Pin-Header-/261879748701?hash=item3cf93fd85d</a>),
cables at $.22 per in lots of $5 (<a href="http://www.ebay.com/itm/20pcs-2-54mm-to-2-54mm-Dupont-Wire-Cable-Connectors-4P-to-4P-Pin-Header-20cm-YG-/111487505711?hash=item19f52c552f" target="_blank">http://www.ebay.com/itm/20pcs-2-54mm-to-2-54mm-Dupont-Wire-Cable-Connectors-4P-to-4P-Pin-Header-20cm-YG-/111487505711?hash=item19f52c552f</a>)
and they are pretty standard for hobbyist projects (and
extremely similar to servo connections). The downsides are
that they have no polarity control, are much more likely to
slide out and take up a lot more board real estate
(translating to either bigger boards or less connectors).<br>
<br>
</div>
Thanks,<br>
</div>
Charlie<br>
</div>
<br>
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<br></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature">-------------------------------------------------------------------------------<br>Carl J. Nobile (Software Engineer)<br><a href="mailto:carl.nobile@gmail.com" target="_blank">carl.nobile@gmail.com</a><br>-------------------------------------------------------------------------------</div>
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