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Calculator Community => Other Calc-Related Projects and Ideas => TI-Nspire => Topic started by: DebboR on December 14, 2012, 02:27:54 pm

Title: Breakout board for the TI nSpire
Post by: DebboR on December 14, 2012, 02:27:54 pm
Hello,

I'm currently developing a cheap breakout board for the TI nSpire series. I am developping this because I don't like to solder directly to my nSpire. This breakout board will be converting the dock connector to a connector with 0.1 inch pitch (normal header size). All 26 pins will be connected to a main connector, with two seperate pin headers for easy connecting of the UART, 3.3V and ground.

I'm letting you know this because if I get the breakout board prototypes, I get 10 pieces. Is anyone intersted in buying such a breakout connector? The price will be around €7 or €8 + shipping. I'm not at home ATM, so I will be posting some pics of the digital PCB render tomorrow.

DebboR
Title: Re: Breakout board for the TI nSpire
Post by: ElementCoder on December 14, 2012, 02:33:20 pm
So it's something like an adapter that makes connecting something to the connnector strip/pins easier? Nice!
Title: Re: Breakout board for the TI nSpire
Post by: Jim Bauwens on December 14, 2012, 02:38:51 pm
Hello,

I'm currently developing a cheap breakout board for the TI nSpire series. I am developping this because I don't like to solder directly to my nSpire. This breakout board will be converting the dock connector to a connector with 0.1 inch pitch (normal header size). All 26 pins will be connected to a main connector, with two seperate pin headers for easy connecting of the UART, 3.3V and ground.

I'm letting you know this because if I get the breakout board prototypes, I get 10 pieces. Is anyone intersted in buying such a breakout connector? The price will be around €7 or €8 + shipping. I'm not at home ATM, so I will be posting some pics of the digital PCB render tomorrow.

DebboR

Hi DebboR,
I'm interested in getting one :)
Something like this is very handy when debugging.
Looking forward to the renders!
Title: Re: Breakout board for the TI nSpire
Post by: DebboR on December 14, 2012, 02:40:25 pm
So it's something like an adapter that makes connecting something to the connnector strip/pins easier? Nice!

Yes! That's exactly what it will be!
Title: Re: Breakout board for the TI nSpire
Post by: Levak on December 14, 2012, 06:05:36 pm
You mean this : http://levak.free.fr/ftp/nspire/dock-nspire/ ?
Title: Re: Breakout board for the TI nSpire
Post by: DebboR on December 14, 2012, 06:19:25 pm
You mean this : http://levak.free.fr/ftp/nspire/dock-nspire/ ?
Yes, but a little more professional... You'll see tomorrow what I mean exactly.
Title: Re: Breakout board for the TI nSpire
Post by: DebboR on December 15, 2012, 10:19:05 am
Hi!

I have finished the v0.1 design today (see pic's below). I just have to decide on the colors (Black, blue or green). The board (and the pin headers) will be €8 (approx. 10$) + shipping. If you are interested, please reply or send me a PM.

Some renders of the different colors:

Black:
(http://imageshack.us/a/img560/1708/blackosb.jpg)

Blue:
(http://imageshack.us/a/img826/3337/blueic.jpg)

Green:
(http://imageshack.us/a/img839/9972/greenum.jpg)

Please let me know what colour you'd prefer to have (I will only be ordering the most wanted colour!)

DebboR
Title: Re: Breakout board for the TI nSpire
Post by: Levak on December 15, 2012, 11:05:04 am
Hi,
I'm a bit confused on the way you'll try to connect to the dock connector ... using a dock connector ...

Indeed, if you look at any Nspire Cradle, you'll see that it has some brushes in order to keep every pin connected :
(http://tiplanet.org/images/dockconn.png)
Title: Re: Breakout board for the TI nSpire
Post by: DebboR on December 15, 2012, 11:09:54 am
Hi,
I'm a bit confused on the way you'll try to connect to the dock connector ... using a dock connector ...

Indeed, if you look at any Nspire Cradle, you'll see that it has some brushes in order to keep every pin connected :
<img>

Yes, you're correct that I haven't explained it at all :-) . This connector is supposed to connect in a totally different way. I will have this board manufactured with 1mm thickness (a little bit thinner than the normal 1.6mm), so that it fits snug between the actual dock connector and the protective sliding cover over it. Onto the pads, a tiny coat of solder is applied so the connections are raised a bit. This should be enough to keep all contacts connected.

DebboR
Title: Re: Breakout board for the TI nSpire
Post by: Adriweb on December 15, 2012, 11:20:45 am
Looks nice, hope it will work nicely with what levak said and the thickness too.

Also, you should put "TI-Nspire" instead of "TI nSpire" :P
Title: Re: Breakout board for the TI nSpire
Post by: DebboR on December 15, 2012, 11:22:35 am
Looks nice, hope it will work nicely with what levak said and the thickness too.

Also, you should put "TI-Nspire" instead of "TI nSpire" :P

Oh, Ok! I always thought it was nSpire... Thanks for the tip!
Title: Re: Breakout board for the TI nSpire
Post by: Levak on December 15, 2012, 11:22:40 am
Hi,
I'm a bit confused on the way you'll try to connect to the dock connector ... using a dock connector ...

Indeed, if you look at any Nspire Cradle, you'll see that it has some brushes in order to keep every pin connected :
<img>

Yes, you're correct that I haven't explained it at all :-) . This connector is supposed to connect in a totally different way. I will have this board manufactured with 1mm thickness (a little bit thinner than the normal 1.6mm), so that it fits snug between the actual dock connector and the protective sliding cover over it. Onto the pads, a tiny coat of solder is applied so the connections are raised a bit. This should be enough to keep all contacts connected.

DebboR
Sorry, but this does not work in real life : if pin 26 and pin 1 are higher of 10µ than the others, numerous pin in the middle wont me connected and will be really annoying while used. Also, some of the pins may create sparks and may crash the calc (already experimented that).

Look at any USB connectors, it also has brushes and stoppers.

Also, 1mm is really tiny and may break, but is not as tiny as it should be to get under the dock cover.

If your system (or prototype) works, nice for you, but I will still have doubt on the reliability of each pins.
Title: Re: Breakout board for the TI nSpire
Post by: DebboR on December 15, 2012, 12:00:24 pm
Hi,
I'm a bit confused on the way you'll try to connect to the dock connector ... using a dock connector ...

Indeed, if you look at any Nspire Cradle, you'll see that it has some brushes in order to keep every pin connected :
<img>

Yes, you're correct that I haven't explained it at all :-) . This connector is supposed to connect in a totally different way. I will have this board manufactured with 1mm thickness (a little bit thinner than the normal 1.6mm), so that it fits snug between the actual dock connector and the protective sliding cover over it. Onto the pads, a tiny coat of solder is applied so the connections are raised a bit. This should be enough to keep all contacts connected.

DebboR
Sorry, but this does not work in real life : if pin 26 and pin 1 are higher of 10µ than the others, numerous pin in the middle wont me connected and will be really annoying while used. Also, some of the pins may create sparks and may crash the calc (already experimented that).

Look at any USB connectors, it also has brushes and stoppers.

Also, 1mm is really tiny and may break, but is not as tiny as it should be to get under the dock cover.

If your system (or prototype) works, nice for you, but I will still have doubt on the reliability of each pins.

Hi.

Thanks for letting me know your opninion about the system. I have chosen the 1mm PCB as it will be the perfect size in my opnion. I have some 1.6mm PCB's laying around, and I have no problem at all wedging them between the dock and the cover. Also, try breaking a 1mm PCB, they're pretty sturdy!

I have actually hacked an old used PCB to try some connections. They don't seem to loose the connection even when I wiggel it around slightly (because they are wedged inbetween the cover and the PCB, plus they flex a bit so even if the edge is slightly higher, it still is able to connect).

As long as you aren't using any inductors or large caps in your external circuit, the arching will not happen on a bad contact (and it will certainly not damage the calc, because if it would, there would be a lot of problems, even with the original TI dock connectors).

I could have used some kind of brush (like in USB-connectors), but I didn't because I wanted to keep the price low. Remember this is still a prototype!

I'm sorry if you disagree with my toughts.

DebboR
Title: Re: Breakout board for the TI nSpire
Post by: Keoni29 on December 15, 2012, 01:01:34 pm
A connector will cost you about $2 or less. Make it optional for the user to intstall this for themselves. Universal prints are the way to go.
Title: Re: Breakout board for the TI nSpire
Post by: DebboR on December 15, 2012, 01:32:49 pm
A connector will cost you about $2 or less. Make it optional for the user to intstall this for themselves. Universal prints are the way to go.

That's a good idea, but I've googled around for a bit, and I can't seem to find a fitting one with a low enough footprint. Do you know a connector up to the job? I'd be happy to add it to the design!

DebboR
Title: Re: Breakout board for the TI nSpire
Post by: DebboR on December 15, 2012, 02:28:44 pm
Hi!

I think I have found a way to increase the reliablity (and make Levak happy :p). I am thinking of taking 26 of these (or similar) connectors: http://www.te.com/catalog/bin/TE.Connect?S=26927&M=PPROP&P=&BML=10576,17560,17553,17559,17770,12594&LG=1&PG=1&IDS=328455,328456,328457,328458,328453,420546,370060,443958,371522,440941,440809,440942,489080,328459,479446,420402,515288,479448,421578,485805&N=11 (http://www.te.com/catalog/bin/TE.Connect?S=26927&M=PPROP&P=&BML=10576,17560,17553,17559,17770,12594&LG=1&PG=1&IDS=328455,328456,328457,328458,328453,420546,370060,443958,371522,440941,440809,440942,489080,328459,479446,420402,515288,479448,421578,485805&N=11)

I will be cutting slots in the PCB at the connector spot, so the spring part fits inside the board. With a board thickness of 1mm, the spring would have 0.6mm to touch the contact (should be enough I think). They will be soldered upside down on the bottom. (I know this is a bit hard to explain. I'll try to draw my idea quickly.)

DebboR
Title: Re: Breakout board for the TI nSpire
Post by: Keoni29 on December 15, 2012, 02:31:11 pm
Farnell will probably have something that will fit. Head over to farnell.com and search for connectors. Enter some specs of the connector.
Title: Re: Breakout board for the TI nSpire
Post by: DebboR on December 15, 2012, 02:32:39 pm
Farnell will probably have something that will fit. Head over to farnell.com and search for connectors. Enter some specs of the connector.

Been there, done that... It's a really strange connector type! But I think my new idea would probably be ok...
I'm going to make a little drawing of it so I can explain it.

EDIT: Here's a little drawing (it's pretty hard with a mouse :p):
(http://imageshack.us/a/img812/2008/springfinger.jpg)

DebboR
Title: Re: Re: Breakout board for the TI nSpire
Post by: TheNlightenedOne on December 15, 2012, 02:44:49 pm
Hey, I might buy one. It looks like it could work!
Title: Re: Breakout board for the TI nSpire
Post by: DebboR on December 15, 2012, 02:56:09 pm
Hey, I might buy one. It looks like it could work!

Thanks! I will try to redesing the board with the new connector idea soon. When this design is done, please PM me to place your order :-).

DebboR
Title: Re: Breakout board for the TI nSpire
Post by: mbmb on January 31, 2013, 07:00:22 pm
Hi Debbor!

Could you please contact me via email? :)
Title: Re: Breakout board for the TI nSpire
Post by: tangrs on February 02, 2013, 04:44:24 am
Ooh, count me interested! My home made ones are getting more annoying to fit on snugly every time. Looking forward to seeing the final product.