Converting Lenovo pointing stick for use on Dell laptop

[bgoodr]

I like the Lenovo T60 trackpoint keyboard, but am stuck with a Dell Latitude E6410 trackpoint keyboard. I do not want to replace the entire Dell laptop with a Lenovo laptop (actually if I do that, I'd first like to go Office Space on it with a baseball bat, then go Amazon shopping for a Lenovo).

The thing I like about the Lenovo T60 laptop's trackpoint, is that it is raised slightly above the caps:



The Dell's trackpoint is depressed to be slightly level with the keyboard. So I find myself in last place with this Dell (reference: http://www.laptopmag.com/articles/looki ... ing-sticks).

The sizes of the posts that the two trackpoints fit onto are of different size, so I cannot simply replace Dell trackpoint with the one from the Lenovo.

Options I thought of:

1. Find a vendor that sells the "muffin top" style of pointing stick but that fits the post on the Dell. But since there is no standard naming convention for these things (reference: http://superuser.com/questions/438749/w ... in-the-mid), searching on the web for what I want is rather daunting (I lack the Google Fu).
2. Purchase a Lenovo trackpoint and a Dell trackpoint. Then, carve off the "muffin top" (so to speak) from the Lenovo trackpoint and somehow glue it to the top of the new Dell trackpoint. But to do so I would need to identify the right types of glue to glue rubber to rubber (rubber cement?).
3. Form the muffin top to the Dell trackpoint using something like Sugru. It would require some gluing and I don't know what would be the correct glue to use with Sugru w.r.t. the rubber on the Dell trackpoint.
4. Form the entire trackpoint out of something like Sugru. The problem is using the existing keyboard as a mold, and I would have to have a method to avoid it from permanently sticking to the keyboard (oil?).
5. Jam some Sugru into the hole on the larger Lenovo trackpoint, squish it down onto the Dell post, let it set, pull it off, carve off the excess. Requires separation agent.

So I'm looking for opinions on the best approach to take here.

Thanks,
Brent

[Findecanor]

You could also search eBay and computer stores for replacement nubs. I know I have seen kits with different replacement nubs of various sizes and shapes at one time or another.

[elecplus]

Another alternative is to buy an inexpensive (less than $20) replacement Lenovo keyboard, remove the pointing device from that, and put it in your Dell. Lotfancy has good replacement keyboards on Amazon for very cheap.

[bgoodr]

Thanks Findecanor and elecplus. I will look into both of those options.

elecplus: I thought that the pointing devices in both Lenovo and Dell keyboards were hardwired in, not parts that can just unplug. Am I thinking straight here? If so, that would mean carving/sawing/soldering which is surely possible, just something I would need to account for if I go that route. But if they are pluggable and compatible that would be even better.

[andrewjoy]

You could buy a repalcement nub for the dell and a lenovo one , and cut the tops off and switch them

[bgoodr]

You could buy a repalcement nub for the dell and a lenovo one , and cut the tops off and switch them

That would leave me with a decapitated nub on the Dell which is no better than the existing Dell nub. I want the "muffin top" on the nub for the one going onto the Dell, hence the idea of gluing as shown in my OP item number 2.

[elecplus]

On most modern laptop keyboards, the mouse pad and pointer stick are an assembly, with wires connecting the pointer to the pad. Sometimes these are soldered, and sometimes they have a tiny pluggable connector. Sorry, I don't know enough specifically about these 2 laptop keyboards to be able to say for sure. I do know that we have repaired laptop keyboard pointer sticks in the past by scrounging parts from different brands of keyboards.

[bgoodr]

elecplus: Got it. I guess I would have to open up both laptops and inspect their connections to see how viable that is.

[andrewjoy]

You could buy a repalcement nub for the dell and a lenovo one , and cut the tops off and switch them

That would leave me with a decapitated nub on the Dell which is no better than the existing Dell nub. I want the "muffin top" on the nub for the one going onto the Dell, hence the idea of gluing as shown in my OP item number 2.

I am a classic nipple man myself.

[HuBandiT]

Have you measured the sizes of the Dell and the ThinkPad stems? How much is the difference? Maybe carving out the hole with an exacto-knife would be an option?

Alternatively, you could CAD and 3D print a dome that fits, from this material: http://www.shapeways.com/materials/elasto-plastic

[bgoodr]

Have you measured the sizes of the Dell and the ThinkPad stems? How much is the difference? Maybe carving out the hole with an exacto-knife would be an option?

Alternatively, you could CAD and 3D print a dome that fits, from this material: http://www.shapeways.com/materials/elasto-plastic

I could not measure the inside of the square hole with any degree of accuracy, but my micrometer fits around the square post. Here are the measurements:

Dell Latitude E6410 pointer post: 0.119 inch

Lenovo T60 pointer post: 0.180 inch

So post on the Lenovo is larger than the post on the Dell.

The OD of the nubs are as follows (inaccurate as they are squishy):

Dell Latitude E6410 nub OD: 0.338 inch

Lenovo T60 nub OD: 0.344 inch

[HuBandiT]

The OD of the nubs are as follows (inaccurate as they are squishy):

For outer diameter measurement you might want to try gently picking up the piece between the micrometer faces, then turning upside down and slowly opening up the micrometer until the piece falls out. If you do it slowly enough - and don't compress the piece much to begin with - then you should get a somewhat more precise measurement.

I could not measure the inside of the square hole with any degree of accuracy, but my micrometer fits around the square post. Here are the measurements:

Put them foot flush on a desktop scanner and scan them at highest physical (non-interpolated) resolution - 2400 DPI on mine, which gets you about a 0.4 mil resolution.

Well then, so you basically need a shim between the thicker hole in the ThinkPad nub and the smaller shaft of the Dell.

Nail polish - at least for a fitting test?

Or you would you prefer to CAD/3D print your way out of this?

[HuBandiT]

Here, 16 micron layers for $5.99 per cubic cm: http://www.shapeways.com/materials/fros ... il-plastic

You could model up the nub with the correct outer and inner sizes, and either print that, take a negative cast, and then cast nubs using that; or model up a two-piece mini mould to be printed from this material, with a runner with inlet port for an off the shelf plastic syringe, and air escape modeled into it, and then you don't need to take a negative cast, but mould nubs directly.

Then you can mould yourself nubs with proper size and good precision all day.

[bgoodr]

Here, 16 micron layers for $5.99 per cubic cm: http://www.shapeways.com/materials/fros ... il-plastic ...
Then you can mould yourself nubs with proper size and good precision all day.

That is tempting from a geeky standpoint, but I'm not so sure UV-baked acrylic has the same feel on the finger as the material used in the original nubs. Or not even sure it matters.

I suspect that the mechanical engineers working at both Dell and Lenovo had good reasons to use the material they used. Perhaps the conversation went something like this: "Joe: Why can't we simply use cheap plastic for these nubs? Fred: We tried that with the usability study and they hated it!"

Speaking of which, what is that material anyhow? Feels like some form of rubber?

I didn't see any form of rubber in shapeways materials list: http://www.shapeways.com/materials

[bhtooefr]

It's worth noting that the E6410 keyboard uses an edge connector that connects it to the palmrest - there's no separate cable going between the pointing stick module (actually, I can't even remember if there's a separate module on that particular keyboard) and the motherboard. I don't have an E6410 in front of me to check, though, and I think I've gotten rid of all of the E6410 keyboards in my inventory (I work for Dell doing field service for a specific client).

[bgoodr]

...there's no separate cable going between the pointing stick module and the motherboard.

Thanks bhtooefr. I have had to return the E6410 back to the Amazon vendor for a replacement. Once I get the new one back in, I can explore some of the various ideas proposed.

[HuBandiT]

Here, 16 micron layers for $5.99 per cubic cm: http://www.shapeways.com/materials/fros ... il-plastic ...
Then you can mould yourself nubs with proper size and good precision all day.

That is tempting from a geeky standpoint, but I'm not so sure UV-baked acrylic has the same feel on the finger as the material used in the original nubs. Or not even sure it matters.

I suspect that the mechanical engineers working at both Dell and Lenovo had good reasons to use the material they used. Perhaps the conversation went something like this: "Joe: Why can't we simply use cheap plastic for these nubs? Fred: We tried that with the usability study and they hated it!"

Oh, my - granted, implied only; but speled out more fully in later comments - suggestion was to use the Shapeways material only as cast/mould to eventually shape modelling rubber, which - is my understanding, but I never actually used modelling materials - should provide a pretty much rubber-like surface and characteristics.

I didn't see any form of rubber in shapeways materials list: http://www.shapeways.com/materials

Shapeways has something they call "Elasto Plastic": http://www.shapeways.com/materials/elasto-plastic - but I haven't tried it yet.

[bgoodr]

Speaking of which, what is that material anyhow? Feels like some form of rubber?

The material is either silicone rubber or what Upgrading and Repairing PCs calls "plastic sandpaper".

[HuBandiT]

Speaking of which, what is that material anyhow? Feels like some form of rubber?

The material is either silicone rubber or

well that is great news then, as the model making rubber I was thinking about also turns out to be silicone rubber. So you should be all set. (Unless you specifically want the plastic sandpaper nub.)

[bgoodr]

Thanks HuBandiT. I'm set to explore these alternatives. I've not decided which alternative to take yet, and that is a good, because I found a driver problem with this trackpoint on Ubuntu which I must fix before I can fix the nub problem: http://askubuntu.com/questions/702140/p ... tude-e6410

[HuBandiT]

Pleasure! Over-engineering is my pastime! Somehow I can't quite get rid of the feeling that it all could be accomplished almost as well with just a shim made out of a piece of postcard paper of the right thickness, cut to the right shape, squished between the ThinkPad nub and the Dell stem.