Kindle 3 serial plug designs

[geekmaster]

If you cannot solder, you could attach wires to aluminum foil with paper clips, if the traces were brought out to larger pads designed for paper clip attachment.

Glue some metal foil to plastic the correct thickness, then cut out non-conductive channels between the traces. Although you do not want to mix different metals at contact points for long term "permanent" use (due to galvanic corrosion), this should not be a problem with a temporary connector.

For more permanent use (such as an external keyboard), I would use copper-clad printed circuit board (PCB) material, but for temporary use (such as debricking) -- hey, whatever gets the job done!

[Shikhin]

Hi,

Originally Posted by geekmaster

[...] If you have access to a piece of circuit board, [...] grind down the circuit board to be thinner to fit in the kindle 3 slot.

Sorry for the late reply. School was re-opening, and thus..

Well, no, I don't have any access to a piece of circuit board - and I'm not sure how easily it'll be available. As for grinding, could sandpaper be used? (if I somehow obtain a piece of circuit board)

I have aluminium foil with me - there's nothing written on it's box - so I'd assume its standard aluminium foil used to wrap food? I have a solder unit - which I don't have much experience with - but I think it could be used to solder wires to the foil.

Regards,
Shikhin

[geekmaster]

Originally Posted by Shikhin

Hi,



Sorry for the late reply. School was re-opening, and thus..

Well, no, I don't have any access to a piece of circuit board - and I'm not sure how easily it'll be available. As for grinding, could sandpaper be used? (if I somehow obtain a piece of circuit board)

I have aluminium foil with me - there's nothing written on it's box - so I'd assume its standard aluminium foil used to wrap food? I have a solder unit - which I don't have much experience with - but I think it could be used to solder wires to the foil.

Regards,
Shikhin

You cannot solder to aluminum with lead or tin-based electrical solders. You can solder to aluminum with special low-melting point aluminum alloys such as Alumaloy, but that is rather expensive.

Aluminum would need a mechanical or conductive paint attachment. You can temporarily connect wires to aluminum foil with alligator clips or paper clips.

You can solder to copper foil. I just found my copper foil today.

Even scrap circuit board salvaged from junk electronics will work. You can use a piece that has some groundplane copper on the surface. Just sand off the paint where you need to connect to it. You can sand or grind it thinner, but do not inhale the dust -- use a dust mask.

Can you get copper foil? Is this for temporary use (recovery)?

[Shikhin]

I guess I can use paper clips then - since I'm not sure where I'll find copper foil.

Yeah, it's for temporary usage - I'm not sure what falls under permanent usage?

[geekmaster]

Originally Posted by Shikhin

I guess I can use paper clips then - since I'm not sure where I'll find copper foil.

Yeah, it's for temporary usage - I'm not sure what falls under permanent usage?

Permanent might be a cable for a foldable serial keyboard, or a serial mouse, that you plan to use many times.

Temporary is just for debricking/recovery (hopefully not many times).

You could take the template or pattern (available elsewhere on mobileread) for the etched circuit board (using only the kindle 3 side of the pattern) and expand the external side with pads large enough to hold paper clips. Then glue the foil onto a suitable thickness piece of plastic (or even glued layers of card stock or paperboard, and when secure, slice out very thin strips of foil to separate the traces. It helps to use a V-shaped hobby knife, but an exacto-style hobby knife will work too if you are careful.

[Shikhin]

Well, as you might know, I'm a bit of a noob - so, well, please don't mind my noobish questions.

a) I wasn't sure a foldable serial keyboard could be used with the kindle. What all would be needed to do something like that?

b) "slice out very thin strips of foil to separate the traces" - I guess this means that I cut out all extra pieces of aluminium so that it matches the kindle 3 serial port template?

[Shikhin]

Oh, and um, what is the Kindle 3's serial connector pinout order, when you hold it in your hands, as you read it.

EDIT: Suppose I do get a copper clad board, as well as an etching solution, but don't have access to a laser printer, can I somehow do it in a easier + secure way?

[geekmaster]

Originally Posted by Shikhin

Oh, and um, what is the Kindle 3's serial connector pinout order, when you hold it in your hands, as you read it.

EDIT: Suppose I do get a copper clad board, as well as an etching solution, but don't have access to a laser printer, can I somehow do it in a easier + secure way?

Pinout:

I am doing this from memory, so it might not be correct. It is probably documented in mobileread along with the connector layout for a circuit board.

On the kindle models that I have examined, the serial port layouts were designed so that it is okay to short together any adjacent pair of pins. They are in the order (starting at the top on kindle 3) TxD, RxD, GND. The kindle 3 also has a 4th pin at the bottom, which when connected to the GND pin above it, enables +3.7v DC power to the top connector (in the top slot). You should verify the information above before using it.

Connector:

You can draw it by hand directly on the copper with a Sharpie or other permanent marker. Instead of ferric chloride etching solution, you can use a mixture of hydrogen peroxide and hydrochloric (muriatic) acid. You can google that... Or you can remove copper strips with a knife, or a small drill bit in a drill press (by milling the voids out), or use a dremel tool (or other rotary tool).

You could probably even do it without metal foil. You could take some copper wire used for house electrical wiring, strip it and pound the wires down flat and thin to make copper strips, and glue those to a piece of stiff paper, or thin plastic, or other nonconductive base material (preferably something you can cut to shape with a pair of scissors).

Or... use your imagination! The point is that there are more ways to do this than I can imagine, so you can do it. It just requires a little ingenuity. I could keep this up all day, and some people would probably respond with even more ideas.

As I mentioned before, you could cut a small piece of copper clad circuit board from a piece of junk electronics. Just route around any existing holes in it. And sand the paint off the copper where you need to etch it. Because it is so small and simple, I would skip the etching and just slice and peel thin strips of copper from between the traces.

You still need to convert the 1.8v TTL serial to something you can use with a computer (RS-232 or USB) even after you bring it out on a cable.