PowerComms v1.3.0
Posted by ZachHoeken
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Re: PowerComms v1.3.0 August 02, 2007 04:22PM |
jmarsden Wrote:
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> BTW, has any thought been given to how one
> "jumpers" wires in an RJ-45 (or RJ-11) jack for
> testing purposes? This is trivial with the
> current connectors (a handy croc clip lead, or two
> crimp connectors and an inch of wire). Let's
> beware of making testing harder by accident.
Now I don't know much about the tests, I'm not that far yet. But it seems to me that if all you have to do is short the RX and TX pins together, that should be pretty easy even in an RJ45/11 jack. The way they're set up (I'm sure you know this, but just for the record), the contacts are spring-loaded and extend a good ways into the socket. Shoving a large, blunt object in there such as a screwdriver should do a fine job of shorting together a couple of leads, especially adjacent ones such as 7 & 8. This is much less convenient than the current method, and you do run a real risk of bending the contacts, but IMO the convenience of pre-made, robust cables makes up for this.
> Stepping back somewhat: we're asking Reprappers to
> make pulleys and belts using boiling water, moulds
> and CAPA, to cut lengths of threaded studding to
> within +/- 0.5mm, and to solder a 3mm wire rope to
> a drilled-out bolt they have created flat areas on
> using a lathe or drill press... compared to that
> kind of thing, making the wires is relatively
> simple, isn't it? I suppose I'm asking whether
> switching to pre-made cables between boards is
> really improving the most pressing and most
> difficult part of the overall construction and
> testing process.
You're right, there are a lot of things about the RepRap project that are probably be more challenging to more people than soldering a handful of cables. BUT, that isn't an excuse to be complacent with the current state of affairs. I get the impression that making this easier will take a good deal less effort all around than tackling those challenges, and something is better than nothing. The right question to ask is "Will this change make a big enough improvement to the project as a whole to justify the time it takes to implement it," not "Is this the absolute biggest issue we face right now?"
EDIT: I forgot to mention it, but I like the idea of RJ-11. It has all the advantages, for this application, of RJ-45, and is better in several areas (size, header size, bending radius, price even). For example, here's a 2 ft (whoops, 61cm
) cable I found in a quick google search. And Mouser sells the headers, I didn't really do a price comparison though. Also, people may be less likely to get confused and try to plug one of the UCBs directly into something they ought'nt.
REEDIT: Here's the link - I must be really slow today. [www.national-tech.com]
Edited 2 time(s). Last edit at 08/02/2007 04:32PM by Kyle Corbitt.
-------------------------------------------------------
> BTW, has any thought been given to how one
> "jumpers" wires in an RJ-45 (or RJ-11) jack for
> testing purposes? This is trivial with the
> current connectors (a handy croc clip lead, or two
> crimp connectors and an inch of wire). Let's
> beware of making testing harder by accident.
Now I don't know much about the tests, I'm not that far yet. But it seems to me that if all you have to do is short the RX and TX pins together, that should be pretty easy even in an RJ45/11 jack. The way they're set up (I'm sure you know this, but just for the record), the contacts are spring-loaded and extend a good ways into the socket. Shoving a large, blunt object in there such as a screwdriver should do a fine job of shorting together a couple of leads, especially adjacent ones such as 7 & 8. This is much less convenient than the current method, and you do run a real risk of bending the contacts, but IMO the convenience of pre-made, robust cables makes up for this.
> Stepping back somewhat: we're asking Reprappers to
> make pulleys and belts using boiling water, moulds
> and CAPA, to cut lengths of threaded studding to
> within +/- 0.5mm, and to solder a 3mm wire rope to
> a drilled-out bolt they have created flat areas on
> using a lathe or drill press... compared to that
> kind of thing, making the wires is relatively
> simple, isn't it? I suppose I'm asking whether
> switching to pre-made cables between boards is
> really improving the most pressing and most
> difficult part of the overall construction and
> testing process.
You're right, there are a lot of things about the RepRap project that are probably be more challenging to more people than soldering a handful of cables. BUT, that isn't an excuse to be complacent with the current state of affairs. I get the impression that making this easier will take a good deal less effort all around than tackling those challenges, and something is better than nothing. The right question to ask is "Will this change make a big enough improvement to the project as a whole to justify the time it takes to implement it," not "Is this the absolute biggest issue we face right now?"
EDIT: I forgot to mention it, but I like the idea of RJ-11. It has all the advantages, for this application, of RJ-45, and is better in several areas (size, header size, bending radius, price even). For example, here's a 2 ft (whoops, 61cm
) cable I found in a quick google search. And Mouser sells the headers, I didn't really do a price comparison though. Also, people may be less likely to get confused and try to plug one of the UCBs directly into something they ought'nt.REEDIT: Here's the link - I must be really slow today. [www.national-tech.com]
Edited 2 time(s). Last edit at 08/02/2007 04:32PM by Kyle Corbitt.
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