Let me know if you have questions or comments!
given the problems that the makesmith had with the encoders, I’m surprised you
went with magnetic ones again. are you reading via PWM again or as a digital
interface?
David Lang
Nope, we’re using the digital interface so we get back an exact number. No trying to read the PWM precisely. The encoder technology has come quite a long way in the last ten years.
@bar I saw your recent Wed update and I’m a bit concerned with the Ethernet cable use since all of the Cat5 cabling I’ve worked with was single strand wire and that by nature is not designed to handle flexing like stranded wiring. But if you found CAT5 cabling which is stranded then all’s good and well.
Connectivity in an Ethernet connector isn’t that great for dirty environments either since it only has a single side of contact while a JST type is going to have 2 or more sides of the connection pin in contact with the mating socket since it’s a 3 sided socket with a spring on the 4th side.
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@bar I saw your recent Wed update and I¢m a bit concerned with the Ethernet
cable use since all of the Cat5 cabling I¢ve worked with was single strand
wire and that by nature is not designed to handle flexing like stranded
wiring. But if you found CAT5 cabling which is stranded then all¢s good and
well.
even if the cables do fail more frequently, having them be something readily
available instead of special order would be a win
Connectivity in an Ethernet connector isn¢t that great for dirty environments
either since it only has a single side of contact while a JST type is going to
have 2 or more sides of the connection pin in contact with the mating socket
since it¢s a 3 sided socket with a spring on the 4th side.
that is an issue, and since it’s not sealed, corrosion can kick in
David Lang
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Those are great points. The ethernet cable that I’ve been playing with is stranded, but I will make sure that we use a stranded cable in the final version as well. The first cable that I grabbed for testing was stranded so I didn’t realize that it is commonly solid core, but a little bit of research shows that you are right. Thanks for pointing that out. That’s something I wasn’t going to double check that I absolutely will now.
That is also a fantastic point. The thing that worries me with the JST-XH is that since all four pins are in a row as the arm moves back and forth it puts quite a bit of strain on the outside pins while the Ethernet connector connector has a lot more protection for them. I 100% agree that you are right about having multiple points of contact be a win for the XH connector. I’ll do some extra testing with putting sawdust in the ports to see how likely it is to cause an issue. Right now I think it’s still a benefit for long term reliability, but I will double check my assumptions about how reliable the ethernet connection is. It’s a good point.
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Because of the timeline I’ve got a couple factories making samples already and I just confirmed with one of them that they are using stranded wire. Thank you again for bringing that up, very much worth double checking that one.
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Solid is for infrastructure wiring, stranded is for patch cables. So just say it’s a long patch cable.
There are lots of different sealed ethernet connectors available in China - just feed the cable through and turn. You find alot used in ip cameras, just a split grommit and a compression connector.
As for corrosion. Shouldn’t be an issue as virtually all connectors are gold plated (high frequency data and corrosion don’t mix) - only issue might be vibration - might be worth testing as they’re not designed to be in high vibration areas, so you could get some issues.
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So what happens if a confused user connects either end of this to their network? I once heard a story of a guy who used standard receptacle plugs to connect their speakers to their sound system. The speakers didn’t last long when a party guest tried plugging them into the wall.
As I’m understanding it, this is to connect the motors/sensors on the short
swinging arms to the electronics, so only about a foot long.
but if you do plug the electronics into your ethernet port, good chance it
would damage the port, if you plug the motor into the port, probably nothing
would happen
David Lang
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Yeah, these cables are only about one foot long and low voltage so the odds of connecting one accidentally to an ethernet port on the wall are hopefully low, but if you did I doubt it would damage anything on either side.