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Discussion Groups | Piclist | RE: Re: Multiple LED's on one pin?
A discussion group for the PICMicro microcontroller. Also called the Microchip PIC, this list is dedicated to the use and abuse of this fine, simple, microcontroller. Close to topic posts are welcome, ie. general electronics.
Multiple LED's on one pin? - smitty505000 - Nov 8 21:55:00 2003
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Hey guys, Do I need a transistor to drive say 10 LED's on one output pin? Its going to be like 220ma. If so what kind of transistor? Thanks, Smitty |
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Re: Multiple LED's on one pin? - Dave Mucha - Nov 9 0:32:00 2003
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--- In , "smitty505000" <smitty505000@y...> wrote: > Hey guys, > > Do I need a transistor to drive say 10 LED's on one output pin? > Its going to be like 220ma. If so what kind of transistor? > > Thanks, > Smitty pn2222 1 amp TO-92 case digi-key PN2222-ND 30 cents |
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RE: Multiple LED's on one pin? - Wouter van Ooijen - Nov 9 3:05:00 2003
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> Do I need a transistor to drive say 10 LED's on one output pin? not if you use 2mA LEDs. you might even succeed in putting two in series, so the total current could be 10 mA. > Its going to be like 220ma. If so what kind of transistor? I would go for a big one to have room for experimental errors, so a TIP120. Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: www.voti.nl consultancy, development, PICmicro products |
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Re: Multiple LED's on one pin? - smitty505000 - Nov 9 12:11:00 2003
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--- In , "Dave Mucha" <davemucha@j...> wrote: > --- In , "smitty505000" <smitty505000@y...> > wrote: > > Hey guys, > > > > Do I need a transistor to drive say 10 LED's on one output pin? > > Its going to be like 220ma. If so what kind of transistor? > > > > Thanks, > > Smitty > pn2222 > > 1 amp > > TO-92 case > > digi-key PN2222-ND 30 cents Thanks so much! I can get them from my favorite place "www.jameco.com" for 5 cents...lol Do I just hook it up with the base on the pic pin and the collector to +5 and emitter to the led? Thanks for the help, Smitty |
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Re: Multiple LED's on one pin? - rtstofer - Nov 9 12:28:00 2003
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Think about putting 2 LEDs in series and 5 parallel strings. So, the dropping resistor for each string is probably 5V - 0.2V (transistor) - 2.4V (1.2Vf per LED) / 0.02A or 120 Ohms. So, you need 5 strings each consisting of 2 LEDs in series with a 120 Ohm resistor. Connect the resistor to +5 then through the LEDs and on to the collector of the transistor. Connect the emitter to ground. Now, since the collector current will be 5 * 0.02A or 0.1A and the transistor gain is probably about 100 you only need 0.1 / 100 base current of 100 uA. Assuming the port can pull to +4V and the base- emitter drop is 0.6V we have 3.4V and 0.0001A or 34K for the base resistor. Choose, say, 10k. So, connect a 10K resistor from the I/O pin to the base. Check to see that the transistor is fully saturated (0.2V give or take from collector to emitter) and reduce the base resistor if necessary. If the port can drive 0.01A then the lower limit of the base resistor is +5V - 0.6V (base emitter drop) / 0.01A or 440 Ohms. --- In , "smitty505000" <smitty505000@y...> wrote: > --- In , "Dave Mucha" <davemucha@j...> wrote: > > --- In , "smitty505000" <smitty505000@y...> > > wrote: > > > Hey guys, > > > > > > Do I need a transistor to drive say 10 LED's on one output > pin? > > > Its going to be like 220ma. If so what kind of transistor? > > > > > > Thanks, > > > Smitty > > > > > > pn2222 > > > > 1 amp > > > > TO-92 case > > > > digi-key PN2222-ND 30 cents > > Thanks so much! I can get them from my favorite > place "www.jameco.com" for 5 cents...lol > Do I just hook it up with the base on the pic pin and the collector > to +5 and emitter to the led? > > Thanks for the help, > Smitty |
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Re: Multiple LED's on one pin? - Phil - Nov 9 12:56:00 2003
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another good source of 2n2222s and TIP120s is www.glitchbuster.com. He's a small guy but honest as the day is long, very prompt and has great prices. the 2n2222's are 12/.98, TIP120s for .39 but more importantly, his PICs are well below the big guys. no minimums and he ships for a flat 1.85 first class (usa, only). Downside? he doesn't have a fancy ordering system and you pay via paypal. I always try to buy from him first. He's always asking for ideas on what to stock. I have no affiliation other than I use him and want to see him remain in biz... Phil --- In , "smitty505000" <smitty505000@y...> wrote: > --- In , "Dave Mucha" <davemucha@j...> wrote: > > --- In , "smitty505000" <smitty505000@y...> > > wrote: > > > Hey guys, > > > > > > Do I need a transistor to drive say 10 LED's on one output > pin? > > > Its going to be like 220ma. If so what kind of transistor? > > > > > > Thanks, > > > Smitty > > > > > > pn2222 > > > > 1 amp > > > > TO-92 case > > > > digi-key PN2222-ND 30 cents > > Thanks so much! I can get them from my favorite > place "www.jameco.com" for 5 cents...lol > Do I just hook it up with the base on the pic pin and the collector > to +5 and emitter to the led? > > Thanks for the help, > Smitty |
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RE: Re: Multiple LED's on one pin? - Wouter van Ooijen - Nov 9 13:04:00 2003
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> another good source of 2n2222s and TIP120s is www.glitchbuster.com. Looks a bit like my shop. I'll look closely at his list to see what i should stock too :) Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: www.voti.nl consultancy, development, PICmicro products |
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Re: Multiple LED's on one pin? - Phil - Nov 9 13:18:00 2003
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what do you charge to ship to seattle?? :( Phil --- In , "Wouter van Ooijen" <wouter@v...> wrote: > > another good source of 2n2222s and TIP120s is www.glitchbuster.com. > > Looks a bit like my shop. I'll look closely at his list to see what i > should stock too :) > > Wouter van Ooijen > > -- ------------------------------------------- > Van Ooijen Technische Informatica: www.voti.nl > consultancy, development, PICmicro products |
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RE: Re: Multiple LED's on one pin? - Bert Drake - Nov 9 13:20:00 2003
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I too
can vouch for www.glitchbuster.com as I've been very happy with my purchases
there.
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RE: Re: Multiple LED's on one pin? - Wouter van Ooijen - Nov 9 13:25:00 2003
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> what do you charge to ship to seattle?? :( I am in the Netherlands, so my (fixed) shipping/handling cost increases from E 3.00 (Netherlands, incl VAT) to E 5.00 (Europe, incl VAT), to US$ 7.35 (World, excl. VAT). So having a shop like mine or glitchbuster's in every country will make the hobby more affordable. BTW for some reason that I don't understand my business one year ago was 1/3 Netherlands, 1/3 Europe, 1/3 rest of the world. Now it is more like 9/10 Netherlands. I do have a web interface for my shop, but I wrote it all myself. Some say that shows. Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: www.voti.nl consultancy, development, PICmicro products |
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Re: Multiple LED's on one pin? - Phil - Nov 9 13:34:00 2003
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Looks like those good dutch boys are getting PIC-religion! By the way, I like your selection. I'll have to point randy (mr glitchbuster) to your site. I think its great how this PIC stuff has a total grass-roots feel to it. Microchip either lucked out or was brilliant in their strategy of giving away the development environment. I wonder how many hobby projects turned into commercial products? Phil --- In , "Wouter van Ooijen" <wouter@v...> wrote: > > what do you charge to ship to seattle?? :( > > I am in the Netherlands, so my (fixed) shipping/handling cost increases > from E 3.00 (Netherlands, incl VAT) to E 5.00 (Europe, incl VAT), to US$ > 7.35 (World, excl. VAT). > > So having a shop like mine or glitchbuster's in every country will make > the hobby more affordable. > > BTW for some reason that I don't understand my business one year ago was > 1/3 Netherlands, 1/3 Europe, 1/3 rest of the world. Now it is more like > 9/10 Netherlands. > > I do have a web interface for my shop, but I wrote it all myself. Some > say that shows. > > Wouter van Ooijen > > -- ------------------------------------------- > Van Ooijen Technische Informatica: www.voti.nl > consultancy, development, PICmicro products |
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Re: Multiple LED's on one pin? - Dave Mucha - Nov 9 13:34:00 2003
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--- In , "Phil" <phil1960us@y...> wrote: > another good source of 2n2222s and TIP120s is www.glitchbuster.com. > He's a small guy but honest as the day is long, very prompt and has > great prices. the 2n2222's are 12/.98, TIP120s for .39 but more > importantly, his PICs are well below the big guys. no minimums and > he ships for a flat 1.85 first class (usa, only). Downside? he > doesn't have a fancy ordering system and you pay via paypal. I > always try to buy from him first. He's always asking for ideas on > what to stock. > > I have no affiliation other than I use him and want to see him remain > in biz... > > Phil you forgot to mention that he does not charge a lot for shipping. op's you did mention that, but it deserves repeating ! Dave |
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RE: Re: Multiple LED's on one pin? - Wouter van Ooijen - Nov 9 14:42:00 2003
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> I wonder how many hobby > projects turned into commercial products? My Wisp628 was originally a hobby project. ZPL (zero-pin bootloader) was a hobby project too, I just sold a buch of development boards (http://sss.voti.nl/dwarf) using this bootloader. The Jal compiler has gone the other way: it is GPL now. Wouter van Ooijen -- ------------------------------------------- Van Ooijen Technische Informatica: www.voti.nl consultancy, development, PICmicro products |
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Re: Re: Multiple LED's on one pin? - Dennis Clark - Nov 9 16:19:00 2003
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D@#%! I'll have to remember this site! DLC Dave Mucha wrote: > --- In , "Phil" <phil1960us@y...> wrote: > >>another good source of 2n2222s and TIP120s is > > www.glitchbuster.com. > >>He's a small guy but honest as the day is long, very prompt and has >>great prices. the 2n2222's are 12/.98, TIP120s for .39 but more >>importantly, his PICs are well below the big guys. no minimums and >>he ships for a flat 1.85 first class (usa, only). Downside? he >>doesn't have a fancy ordering system and you pay via paypal. I >>always try to buy from him first. He's always asking for ideas on >>what to stock. >> >>I have no affiliation other than I use him and want to see him > > remain > >>in biz... >> >>Phil > > you forgot to mention that he does not charge a lot for shipping. > > op's you did mention that, but it deserves repeating ! > Dave > > to unsubscribe, go to http://www.yahoogroups.com and follow the instructions > > -- --------------------------------------------------------------------- * Dennis Clark http://www.techtoystoday.com * * "Programming and Customizing the OOPic Microcontroller" Mcgraw-Hill * --------------------------------------------------------------------- |
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Re: Multiple LED's on one pin? - smitty505000 - Nov 10 0:09:00 2003
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Wow! Someones an electrical engineer. Thanks for the info. I think I am going with the 2x5 series parallel. I have three boards to make, two with 20 led's each and one with 69 led's. I am going to have one pic16f628 drive the two with 20 and one pic for the board with 69 led's. The patterns are all different. If you are wondering what they are for, they are logic displays for a full size R2D2 I am building. Smitty --- In , "rtstofer" <rstofer@p...> wrote: > > Think about putting 2 LEDs in series and 5 parallel strings. So, > the dropping resistor for each string is probably 5V - 0.2V > (transistor) - 2.4V (1.2Vf per LED) / 0.02A or 120 Ohms. So, you > need 5 strings each consisting of 2 LEDs in series with a 120 Ohm > resistor. > > Connect the resistor to +5 then through the LEDs and on to the > collector of the transistor. Connect the emitter to ground. > > Now, since the collector current will be 5 * 0.02A or 0.1A and the > transistor gain is probably about 100 you only need 0.1 / 100 base > current of 100 uA. Assuming the port can pull to +4V and the base- > emitter drop is 0.6V we have 3.4V and 0.0001A or 34K for the base > resistor. Choose, say, 10k. So, connect a 10K resistor from the > I/O pin to the base. Check to see that the transistor is fully > saturated (0.2V give or take from collector to emitter) and reduce > the base resistor if necessary. > > If the port can drive 0.01A then the lower limit of the base > resistor is +5V - 0.6V (base emitter drop) / 0.01A or 440 Ohms. > > --- In , "smitty505000" <smitty505000@y...> > wrote: > > --- In , "Dave Mucha" <davemucha@j...> > wrote: > > > --- In , "smitty505000" > <smitty505000@y...> > > > wrote: > > > > Hey guys, > > > > > > > > Do I need a transistor to drive say 10 LED's on one output > > pin? > > > > Its going to be like 220ma. If so what kind of transistor? > > > > > > > > Thanks, > > > > Smitty > > > > > > > > > pn2222 > > > > > > 1 amp > > > > > > TO-92 case > > > > > > digi-key PN2222-ND 30 cents > > > > Thanks so much! I can get them from my favorite > > place "www.jameco.com" for 5 cents...lol > > Do I just hook it up with the base on the pic pin and the > collector > > to +5 and emitter to the led? > > > > Thanks for the help, > > Smitty |
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Re: Re: Multiple LED's on one pin? - John Remington - Nov 10 9:49:00 2003
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www.glitchbuster.com, 12 for a buck. Randy's great, ships right away, and you don't have a $25 minimum and $5 in shipping costs. --- Dave Mucha <> wrote: > --- In , "smitty505000" <smitty505000@y...> > wrote: > > Hey guys, > > > > Do I need a transistor to drive say 10 LED's on one output pin? > > > Its going to be like 220ma. If so what kind of transistor? > > > > Thanks, > > Smitty > pn2222 > > 1 amp > > TO-92 case > > digi-key PN2222-ND 30 cents __________________________________ |
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Re: Multiple LED's on one pin? - smitty505000 - Nov 16 13:10:00 2003
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rstofer, Thanks for the info! It works perfect! I have 70 LED's 7 sets on 7 pins wired in 2 series 5 parallel and she works like a charm. Take a look on my page to see it. http://home.cfl.rr.com/smittyshobbies/r2d2.htm Thanks, Smitty --- In , "rtstofer" <rstofer@p...> wrote: > > Think about putting 2 LEDs in series and 5 parallel strings. So, > the dropping resistor for each string is probably 5V - 0.2V > (transistor) - 2.4V (1.2Vf per LED) / 0.02A or 120 Ohms. So, you > need 5 strings each consisting of 2 LEDs in series with a 120 Ohm > resistor. > > Connect the resistor to +5 then through the LEDs and on to the > collector of the transistor. Connect the emitter to ground. > > Now, since the collector current will be 5 * 0.02A or 0.1A and the > transistor gain is probably about 100 you only need 0.1 / 100 base > current of 100 uA. Assuming the port can pull to +4V and the base- > emitter drop is 0.6V we have 3.4V and 0.0001A or 34K for the base > resistor. Choose, say, 10k. So, connect a 10K resistor from the > I/O pin to the base. Check to see that the transistor is fully > saturated (0.2V give or take from collector to emitter) and reduce > the base resistor if necessary. > > If the port can drive 0.01A then the lower limit of the base > resistor is +5V - 0.6V (base emitter drop) / 0.01A or 440 Ohms. > > --- In , "smitty505000" <smitty505000@y...> > wrote: > > --- In , "Dave Mucha" <davemucha@j...> > wrote: > > > --- In , "smitty505000" > <smitty505000@y...> > > > wrote: > > > > Hey guys, > > > > > > > > Do I need a transistor to drive say 10 LED's on one output > > pin? > > > > Its going to be like 220ma. If so what kind of transistor? > > > > > > > > Thanks, > > > > Smitty > > > > > > > > > pn2222 > > > > > > 1 amp > > > > > > TO-92 case > > > > > > digi-key PN2222-ND 30 cents > > > > Thanks so much! I can get them from my favorite > > place "www.jameco.com" for 5 cents...lol > > Do I just hook it up with the base on the pic pin and the > collector > > to +5 and emitter to the led? > > > > Thanks for the help, > > Smitty |
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Re: Multiple LED's on one pin? - rtstofer - Nov 16 14:45:00 2003
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Very impressive! --- In , "smitty505000" <smitty505000@y...> wrote: > rstofer, > > Thanks for the info! It works perfect! I have 70 LED's 7 sets on 7 > pins wired in 2 series 5 parallel and she works like a charm. Take a > look on my page to see it. > http://home.cfl.rr.com/smittyshobbies/r2d2.htm > Thanks, > Smitty > > --- In , "rtstofer" <rstofer@p...> wrote: > > > > Think about putting 2 LEDs in series and 5 parallel strings. So, > > the dropping resistor for each string is probably 5V - 0.2V > > (transistor) - 2.4V (1.2Vf per LED) / 0.02A or 120 Ohms. So, you > > need 5 strings each consisting of 2 LEDs in series with a 120 Ohm > > resistor. > > > > Connect the resistor to +5 then through the LEDs and on to the > > collector of the transistor. Connect the emitter to ground. > > > > Now, since the collector current will be 5 * 0.02A or 0.1A and the > > transistor gain is probably about 100 you only need 0.1 / 100 base > > current of 100 uA. Assuming the port can pull to +4V and the base- > > emitter drop is 0.6V we have 3.4V and 0.0001A or 34K for the base > > resistor. Choose, say, 10k. So, connect a 10K resistor from the > > I/O pin to the base. Check to see that the transistor is fully > > saturated (0.2V give or take from collector to emitter) and reduce > > the base resistor if necessary. > > > > If the port can drive 0.01A then the lower limit of the base > > resistor is +5V - 0.6V (base emitter drop) / 0.01A or 440 Ohms. > > > > > > > > --- In , "smitty505000" <smitty505000@y...> > > wrote: > > > --- In , "Dave Mucha" <davemucha@j...> > > wrote: > > > > --- In , "smitty505000" > > <smitty505000@y...> > > > > wrote: > > > > > Hey guys, > > > > > > > > > > Do I need a transistor to drive say 10 LED's on one > output > > > pin? > > > > > Its going to be like 220ma. If so what kind of transistor? > > > > > > > > > > Thanks, > > > > > Smitty > > > > > > > > > > > > pn2222 > > > > > > > > 1 amp > > > > > > > > TO-92 case > > > > > > > > digi-key PN2222-ND 30 cents > > > > > > Thanks so much! I can get them from my favorite > > > place "www.jameco.com" for 5 cents...lol > > > Do I just hook it up with the base on the pic pin and the > > collector > > > to +5 and emitter to the led? > > > > > > Thanks for the help, > > > Smitty |
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