Quite true. The contacts still need to be provided in another way.
I won’t be surprised to find multi-strand printers in use, with the ability to print a conductive material. Maybe already available.
But as you say, Richard, gold plated contacts are the best. Silver is almost as good. Probably not printable yet.
The designs on thingiverse are just the plastic parts, arms and bases. Additional work is needed to provide reliable contacts.
Andrew VK1DA/VK2UH
Andrew,
It would be possible to coat a plastic contact with graphite paint and then plate on copper followed by (my preference) Rhodium. Resists oxidation, hard wearing, good conductor. Expensive. Used in military stuff that sits in its box for 15 years and then must work no questions asked. Platinum maybe about the same price but not sure about plating it. Even though the cost might be $3,000 per ounce you only need a thin coating < 1 mg to have an excellent contact. Tungsten was favoured in car ignition breakers because of its toughness and availability. Usually sintered in place - hard with plastic base.
Gold looks good and solders like a flash but it’s soft and not wear resistant. Worse than copper. When used in contacts silver is also soft so usually alloyed with something else.
With solid state switches being used for most everything the skills of making durable low maintenance contacts has probably been lost.
EOE
73
Ron
VK3AFW
Just thinking aloud, but if you were making your own 3D printed key (or any other type) you could maybe use contacts recovered from an old relay. Gold, silver and platinum are not uncommon. A pair of basic gold or silver ear studs (or other body part studs :o) would probably come in under the price of a Palm key, and could make good contacts…
The problem of using “old recovered X” is whether there is sufficient “old recovered X” for a production run whether the production run is a real produce keys for sale run, or repeatability for anyone using your design files.
If you have your own 3d printer you can play making one offs and improving. But for a design to be reproducible to the extent that I can get the model files, print one, find a old X and strip and make a key that works as well as the prototype is hard.
It’s an interesting subject. Maybe a run of contacts will need to made at some financial risk to make 3d printing repeatable. I’m doing something similar at present looking at some way of making a repeatable 13 (or 23cms) antenna design that can be easily built by people who know which end of a soldering iron to hold but don’t have basic metal bashing facilities. Whilst making money out of the idea would be nice, my aim is to make it so more people can buy some cheap(ish) microwave gear and make up some real gain antennas and go and have regular QSOs on these bands as easy as on 2m and 70cms.
For those that have had problems with the cable or connector used for the Palm Paddle - here’s a retrofit idea.
All the usual caveats here about me representing nothing about how well this may or may not work for you and that you take all the responsibility for working on your own stuff.
Remove the base of the Palm Paddle and ease the paddle out of the case.
Use a thin utility knife to break the glue bond between the connector and the paddle. Mine separated very easily.
With a pin or sharp utility knife, press the release on the connector pins, push them out, and remove the connector body.
Cut the pins off, leaving the wires as long as possible and strip a tiny amount from the end of each wire.
With some small gauge wire, extend the length of the red and brown wires. Be neat about it and use a short bit of heat shrink over the solder joints.
For the connector specified below, the rear pin goes to the black wire, the brown wire connects to the front pin (nearest the opening) and the red wire to the last spot. The connector is a Kobiconn Phone Connector, 3.5mm stereo open circuit, Mouser 161-4033-E.
A bit of contact cement under the connector finishes the work. The new connector almost looks like it belongs.
Many audio stereo extension cables will work - the photos show a very common computer audio cable.
My design will likely use semi-flex 0.8 PCB strips for the contacts, same as the Palm Pico.
Martin
This topic has drifted away from the subject, which did not deserve to be derailed. I don’t have the privileges to split a discussion but the new discussion is valid in its own right. Could someone with the privileges do that, if they agree with the idea?
Thanks VK1DA/VK2UH
Seems a very sensible idea Andrew. I think I’ll move the Palm replacement messages to one new thread unless anyone has a better idea.
I don’t know. Replacements seems a logical continuation of a thread that has run out of steam.
