[TriEmbed] Favourite electrical connectors?

Sun Sep 27 21:43:03 CDT 2015

Thank you all.  That is some good info.

The resistance requirements that Pete has pointed out for CAN bus had me
looking stuff up all weekend.  I wasn't aware of the terminating resistor
requirement, which complicates making a plug and play setup enormously.
Researching that also lead to the revelation that CAN bus really doesn't
like T-spurs (advised to keep under 1.5 meters).  In combination with some
other factors, it throws the viability of the whole concept into doubt.

I've been looking into using a I2C based bus instead.  There are some real
upsides (such as $.65 microcontrollers which can use it) but special
consideration has to be made for the range issues (though those may be
mitigated by using range extender chips such as the

P82B715).  Until the "which protocol" issue is resolved, it will be
difficult to move forward with the board design.

Thanks again,

Charlie

On Fri, Sep 25, 2015 at 6:10 PM, Shane Trent via TriEmbed <
triembed at triembed.org> wrote:

> Charlie,
>
> They aren't fancy but for prototyping I am a fan on the JST SM connectors
> with attached wires from Adafruit. They are reasonably small, lock in place
> and give you polarity protection. Not something for production but you get
> proper machine crimped pins in the connector and it lets you get up and
> running quickly.
>
> https://www.adafruit.com/products/578
>
> Shane
>
> On Fri, Sep 25, 2015 at 3:22 PM, Robert Gasiorowski via TriEmbed <
> triembed at triembed.org> wrote:
>
>> My favorite is Eurostyle connector from Molex, 39501 and 39502 series.
>>
>>
>>
>> http://www.ebay.com/sch/i.html?_odkw=3.5mm+connector+terminal+green&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.X3.5mm+connector+pluggable+green.TRS0&_nkw=3.5mm+connector+pluggable+green&_sacat=0
>>
>>
>> On Fri, Sep 25, 2015 at 1:17 PM, Pete Soper via TriEmbed <
>> triembed at triembed.org> wrote:
>>
>>>
>>>
>>> On 09/25/2015 01:06 PM, Carl Nobile wrote:
>>>
>>> Pete,
>>>
>>> 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.
>>>
>>> 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,
>>>
>>> Tell this to the fractional billions of people using RJ45 connectors.
>>> They're identical to RJ11 but eight vs six connections. I agree 200% that
>>> inserting and crimping UTP into an RJ45 or RJ11 is a certified, genuine
>>> pain in the you know what, but figured labor costs in this case are
>>> considered zero. :-)
>>>
>>> -Pete
>>>
>>>
>>> four wires, two for the CAN protocol and two for power. Each one will go
>>> to some sort of sensor.
>>>
>>> ~Carl
>>>
>>>
>>> On Fri, Sep 25, 2015 at 12:46 PM, Pete Soper via TriEmbed <
>>> <triembed at triembed.org>triembed at triembed.org> wrote:
>>>
>>>> The cable requirement for CANBUS is explicitly dictated by the bus
>>>> standard (covered in this TI blurb
>>>> <http://www.ti.com/lit/an/slla270/slla270.pdf>): 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.
>>>>
>>>> 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 Digikey jack
>>>> <http://www.digikey.com/product-detail/en/A-2014-0-4-R/AE10390-ND/2183641>
>>>> (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.
>>>>
>>>> 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.
>>>>
>>>> -Pete
>>>>
>>>>
>>>> On 09/25/2015 10:18 AM, Charles West via TriEmbed wrote:
>>>>
>>>> Hello,
>>>>
>>>> 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?
>>>>
>>>> Pros/cons:
>>>> DF13:
>>>> 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).
>>>>
>>>> Vertical Headers:
>>>> The plus is I can get break apart SMD headers at roughly $.05 each
>>>> including shipping at lots of $5 (
>>>> http://www.ebay.com/itm/10pcs-2-54MM-1-40Pin-SMD-SMT-1-40Pin-Male-Single-Row-Pin-Header-/261879748701?hash=item3cf93fd85d),
>>>> cables at $.22 per in lots of $5 (
>>>> <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>
>>>> 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)
>>>> 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).
>>>>
>>>> Thanks,
>>>> Charlie
>>>>
>>>>
>>>> _______________________________________________
>>>> Triangle, NC Embedded Computing mailing listTriEmbed at triembed.orghttp://mail.triembed.org/mailman/listinfo/triembed_triembed.org
>>>> TriEmbed web site: http://TriEmbed.org
>>>>
>>>>
>>>>
>>>> _______________________________________________
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>>>>
>>>>
>>>
>>>
>>> --
>>>
>>> -------------------------------------------------------------------------------
>>> Carl J. Nobile (Software Engineer)
>>> carl.nobile at gmail.com
>>>
>>> -------------------------------------------------------------------------------
>>>
>>>
>>>
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>>>
>>>
>>
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>>
>
>
> --
> A blog about some of my projects.  http://fettricks.blogspot.com/
>
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