From: <tim...@co...> - 2007-01-10 19:30:47
|
Hi Kate, Are you refering to the input voltage from your power supply, or the reverse EMI from the motors? If you have a regulated supply then the protection is in the supply. Tim -------------- Original message ---------------------- From: "Dave Hylands" <dhy...@gm...> > HI Kate, > > > I've got a gumstix/roboaudiostix combination working (thanks to all the help > > from this list) and I want to use the robostix to drive motors and receive > > sensor data. My electronics knowledge isn't great and I would like to build > > a protection board for the robostix in case I accidently feed it the > > incorrect voltage or too much current etc. Do I only need zener diodes to > > limit the voltage and resistors to limit the current? Also, does the board > > have any built-in protection? Any advice on what I need would be greatly > > appreciated. > > There isn't any builtin circuitry to prevent that type of problem > (hooking up to high a voltage). > > Personally, I tend to use buffer chips, although these generally only > work when you have unidirectional signals. > > Having an inline resistor is definitely a good idea. I've never used > zener diodes like you suggested, so I don't know how good/bad they > might be. > > For the ultimate protection you can use opto-isolators. You just need > to be careful of the speed rating. Some are quite slow. > > -- > Dave Hylands > Vancouver, BC, Canada > http://www.DaveHylands.com/ > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share your > opinions on IT & business topics through brief surveys - and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users |
From: Kate M. <kat...@gm...> - 2007-01-11 08:45:33
|
Hi Dave Thanks for the suggestions... I will look into the opto-isolators. That's probably a safe bet :) And thanks again for all the help.. I wouldn't be getting anywhere without this list. Hi Tim What I am worrying about is that during development and testing there will be a mistake in some of my external sensor circuitry and don't want to feed the incorrect input to the robostix and damage it. I was just thinking of building a general purpose board as a buffer between the robostix inputs and outputs and my circuitry to prevent any accidental over-voltage or too much current. About the motors, sorry but I am really not an expert... will reverse EMI be a problem if I am driving the motors with H-bridge chips? Thanks Kate > > > > Hi Kate, > > Are you refering to the input voltage from your power supply, or the > reverse EMI from the motors? > > If you have a regulated supply then the protection is in the supply. > > Tim > > -------------- Original message ---------------------- > From: "Dave Hylands" <dhy...@gm...> > > HI Kate, > > > > > I've got a gumstix/roboaudiostix combination working (thanks to all > the help > > > from this list) and I want to use the robostix to drive motors and > receive > > > sensor data. My electronics knowledge isn't great and I would like to > build > > > a protection board for the robostix in case I accidently feed it the > > > incorrect voltage or too much current etc. Do I only need zener diodes > to > > > limit the voltage and resistors to limit the current? Also, does the > board > > > have any built-in protection? Any advice on what I need would be > greatly > > > appreciated. > > > > There isn't any builtin circuitry to prevent that type of problem > > (hooking up to high a voltage). > > > > Personally, I tend to use buffer chips, although these generally only > > work when you have unidirectional signals. > > > > Having an inline resistor is definitely a good idea. I've never used > > zener diodes like you suggested, so I don't know how good/bad they > > might be. > > > > For the ultimate protection you can use opto-isolators. You just need > > to be careful of the speed rating. Some are quite slow. > > > > -- > > Dave Hylands > > Vancouver, BC, Canada > > http://www.DaveHylands.com/ > > > > > ------------------------------------------------------------------------- > > Take Surveys. Earn Cash. Influence the Future of IT > > Join SourceForge.net's Techsay panel and you'll get the chance to share > your > > opinions on IT & business topics through brief surveys - and earn cash > > > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > > _______________________________________________ > > gumstix-users mailing list > > gum...@li... > > https://lists.sourceforge.net/lists/listinfo/gumstix-users > > > |
From: Fadjar T. <fa...@si...> - 2007-01-11 08:51:55
|
Dear All, Is it possible to ask the Gumstix manufacture to reduce the size of the wifistix and connex? Regards, Fadjar T |
From: group t. <mo...@gm...> - 2007-01-11 10:19:23
|
is this a request for a new product? otherwise, it would require a new turn of boards and a redesign--highly unlikely. On 1/11/07, Fadjar Tandabawana <fa...@si...> wrote: > > Dear All, > > Is it possible to ask the Gumstix manufacture to reduce the size of the > wifistix and connex? > > Regards, > Fadjar T > > > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get the chance to share > your > opinions on IT & business topics through brief surveys - and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > |
From: Fadjar T. <fa...@si...> - 2007-01-11 12:48:13
|
Just curious if there any possibilities... I just started new project to build the new phone with gumstix product but the size of wifistix + connex still bigger than I expected. If there any information about this regarding the manufacture, please let me know.. Regards, Fadjar T group two wrote: > is this a request for a new product? otherwise, it would require a > new turn > of boards and a redesign--highly unlikely. > > On 1/11/07, Fadjar Tandabawana <fa...@si...> wrote: >> >> Dear All, >> >> Is it possible to ask the Gumstix manufacture to reduce the size of the >> wifistix and connex? >> >> Regards, >> Fadjar T >> >> >> >> ------------------------------------------------------------------------- >> >> Take Surveys. Earn Cash. Influence the Future of IT >> Join SourceForge.net's Techsay panel and you'll get the chance to share >> your >> opinions on IT & business topics through brief surveys - and earn cash >> http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV >> >> _______________________________________________ >> gumstix-users mailing list >> gum...@li... >> https://lists.sourceforge.net/lists/listinfo/gumstix-users >> > |
From: Don A. <do...@gu...> - 2007-01-11 15:46:54
|
The connex motherboards has the now "standardized" 80 mm x 20 mm dimension. Many of our daughterboards have that same dimension. Volume orders of gumstix motherboards and expansion boards may be customized by the removal of components from the retail products. However, dimensional changes are not available from Gumstix. Don @ Gumstix +++++++++ At 7:48 PM +0700 1/11/07, Fadjar Tandabawana wrote: Just curious if there any possibilities... I just started new project to build the new phone with gumstix product but the size of wifistix + connex still bigger than I expected. If there any information about this regarding the manufacture, please let me know.. Regards, Fadjar T group two wrote: > is this a request for a new product? otherwise, it would require a > new turn > of boards and a redesign--highly unlikely. > > On 1/11/07, Fadjar Tandabawana <fa...@si...> wrote: >> >> Dear All, >> >> Is it possible to ask the Gumstix manufacture to reduce the size of the >> wifistix and connex? >> >> Regards, >> Fadjar T >> >> >> >> ----------------------------------------------------------------------- ==================================================================== Don Anderson http://www.gumstix.com ==================================================================== -- |
From: <tim...@co...> - 2007-01-11 22:53:14
|
Hi Kate, It's a very good idea to protect your gumstix. Opto-isolators are a good solution. As you know reverse emi is where the motor turns in to a generator and feed voltage back into the circuit. This voltage can be twice the voltage driving the motor. What I do is spec a high voltage/current driver. I designed a circuit that drives a 240 volt 2 horse power motor. I had to spec a 600 volt 40 amp alternister even though a 400 volt 10 amp device could drive the motor, it would short out when the circuit was disabled. Tim -------------- Original message ---------------------- From: "Kate McWilliams" <kat...@gm...> > Hi Dave > > Thanks for the suggestions... I will look into the opto-isolators. That's > probably a safe bet :) And thanks again for all the help.. I wouldn't be > getting anywhere without this list. > > Hi Tim > > What I am worrying about is that during development and testing there will > be a mistake in some of my external sensor circuitry and don't want to feed > the incorrect input to the robostix and damage it. I was just thinking of > building a general purpose board as a buffer between the robostix inputs and > outputs and my circuitry to prevent any accidental over-voltage or too much > current. About the motors, sorry but I am really not an expert... will > reverse EMI be a problem if I am driving the motors with H-bridge chips? > > Thanks > Kate > > > > > > > > > Hi Kate, > > > > Are you refering to the input voltage from your power supply, or the > > reverse EMI from the motors? > > > > If you have a regulated supply then the protection is in the supply. > > > > Tim > > > > -------------- Original message ---------------------- > > From: "Dave Hylands" <dhy...@gm...> > > > HI Kate, > > > > > > > I've got a gumstix/roboaudiostix combination working (thanks to all > > the help > > > > from this list) and I want to use the robostix to drive motors and > > receive > > > > sensor data. My electronics knowledge isn't great and I would like to > > build > > > > a protection board for the robostix in case I accidently feed it the > > > > incorrect voltage or too much current etc. Do I only need zener diodes > > to > > > > limit the voltage and resistors to limit the current? Also, does the > > board > > > > have any built-in protection? Any advice on what I need would be > > greatly > > > > appreciated. > > > > > > There isn't any builtin circuitry to prevent that type of problem > > > (hooking up to high a voltage). > > > > > > Personally, I tend to use buffer chips, although these generally only > > > work when you have unidirectional signals. > > > > > > Having an inline resistor is definitely a good idea. I've never used > > > zener diodes like you suggested, so I don't know how good/bad they > > > might be. > > > > > > For the ultimate protection you can use opto-isolators. You just need > > > to be careful of the speed rating. Some are quite slow. > > > > > > -- > > > Dave Hylands > > > Vancouver, BC, Canada > > > http://www.DaveHylands.com/ > > > > > > > > ------------------------------------------------------------------------- > > > Take Surveys. Earn Cash. Influence the Future of IT > > > Join SourceForge.net's Techsay panel and you'll get the chance to share > > your > > > opinions on IT & business topics through brief surveys - and earn cash > > > > > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > > > _______________________________________________ > > > gumstix-users mailing list > > > gum...@li... > > > https://lists.sourceforge.net/lists/listinfo/gumstix-users > > > > > > |
From: Ian S. <it...@cs...> - 2007-01-10 20:29:56
|
i was looking at the breakout board and there are lines labeled miso mosi etc, does that mean there is SPI access on the breakout? if so how hard is it to access? -Ian |
From: Andrei R. <ar...@ya...> - 2007-01-10 20:37:49
|
Not that hard, I'm using 3 SPI devices connected to the breakout-gs, Robostix is one of them. Do you have any particular problem ? --- Ian Smith <it...@cs...> wrote: > i was looking at the breakout board and there are > lines labeled miso > mosi etc, does that mean there is SPI access on the > breakout? if so how > hard is it to access? > -Ian > > ------------------------------------------------------------------------- > Take Surveys. Earn Cash. Influence the Future of IT > Join SourceForge.net's Techsay panel and you'll get > the chance to share your > opinions on IT & business topics through brief > surveys - and earn cash > http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > |