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Re: LM3914 vs LM3915 vs LM3916
--- Curtis Sakima <electronichobbyist@y...> wrote:
I saw on this group .... somebody wanted to know the[snip] You're right ... that schematically, the LM39XX chip[snip] The 3916 is calibrated by dB's (like in audio/VUCurtis, that was me asking. Basically I was asking if there was any benefit of one over the other. The original plan was to drive a few (10-15) LEDs as a throttle position indicator by using a linear slide pot to change the reference voltage. A few here suggested the LM3916. In looking for the chip to purchase, it was discontinued, but there were references to the 3914, and 3915 chips. Now with your explanation, it seems the 3914, would be the chip to use since I want to measure voltage? Brian |
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Re: PIC resources
Mounir Shita
¿ªÔÆÌåÓýI
would disagree with everyone who thinks PIC discussions doesn't belong to this
group either. I think we're beyond the times where you could do everything with
discrete components. These days microcontrollers belong as much to Basic
Electronics as a transistor and a diode.
?
Mounir
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Re: Energy
d nixon
Yeah, solar...wind...geothermal. But what does this have to do with electronics?
I suggest an alternative energy group/website. From: "angtengchat" <angtengchat@...> _________________________________________________________________ Get your FREE download of MSN Explorer at |
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Re: PIC resources
d nixon
You'd get a better answer on the PIC group.
From: "Teodoro M. Villamarzo" <tedmv@...> _________________________________________________________________ Get your FREE download of MSN Explorer at |
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Re: CPU Question
aconto
I agree.... I am not a fan of proprietary hardware or software for that
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matter -----Original Message-----
From: Jim Purcell [mailto:jpurcell@...] Sent: Thursday, November 01, 2001 2:16 PM To: Electronics_101@... Subject: Re: [Electronics_101] Re: CPU Question aconite, I read an article where compac and hp are merging...crazyYes, both were startup companies, HP in the thirties and I think Compaq in the seventies. Both had a good rep at one time. Right now those HP boxes are the ugliest things I have ever seen. A few years ago I didn't care, I looked at the features. But now I hate modular boxes. I want a nice square one that will be easy to upgrade, especially the CDs. etc. Jim To unsubscribe from this group, send an email to: Electronics_101-unsubscribe@... Your use of Yahoo! Groups is subject to |
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Re: CPU Question
Jim Purcell
aconite,
I read an article where compac and hp are merging...crazyYes, both were startup companies, HP in the thirties and I think Compaq in the seventies. Both had a good rep at one time. Right now those HP boxes are the ugliest things I have ever seen. A few years ago I didn't care, I looked at the features. But now I hate modular boxes. I want a nice square one that will be easy to upgrade, especially the CDs. etc. Jim |
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Re: CPU Question
aconto
I read an article where compac and hp are merging...crazy
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Show quoted text
-----Original Message-----
From: Daniel Imfeld [mailto:dimfeld@...] Sent: Thursday, November 01, 2001 12:15 PM To: Electronics_101@... Subject: [Electronics_101] Re: CPU Question I read about a major company, I think it was HP, that has created a Beowulf cluster (a group of cheap PCs linked together to create a supercomputer) that qualifies as one of the more powerful supercomputers in existence. One advantage of this method, they said, is that when you add and remove computers from the cluster, the total processing power changes linearly, so it's easy to calculate how many computers you'll need for a specific task. Also, it makes it easier to split the processing time between two projects if the need arises. I think they used something more powerful than 486's and Pentiums, but I can't remember exactly what they used, as I read about it a few months ago. I know that they used only cheap off-the-shelf PCs though. If I remember correctly, they run it on Linux, or some variation of it, with a master computer (or computers) that controls all the others, similar to Stanford's Folding@home project, but probably more optimized for LAN usage and proprietary things. So I suppose if you do it correctly, you can get great results, although I imagine that it would take quite a bit of work to set everything up. Daniel Imfeld ----- Original Message ----- Saad, Old PC's can beI've heard about that but I wonder whether it is a practical idea. The controlling software that would assign parts of the computing task to various computers would have to be vary sophisticated. Then there would be the distances between computers. It would probably be better to just use the system cards otherwise all those old power supplies would consume lots of energy and there'd be the problem of varying power supply connectors and voltage requirements, maybe some kind of bus communication would be necessary to avoid port bottlenecks. It would certainly be a good project for some IT students but I think the work involved in making it happen in a real world situation would more than cancel most benefits. But then I could be wrong, wouldn't be the first or last time. Jim To unsubscribe from this group, send an email to: Electronics_101-unsubscribe@... Your use of Yahoo! Groups is subject to |
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Re: CPU Question
Jim Purcell
Daniel,
I read about a major company, I think it was HP, that has created a BeowulfIf that is the case I doubt that they are using very old computers. And it would seem wiser to dump everything but the system board. A few larger power supplies are better than many small ones. Jim |
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Re: CPU question
Jim Purcell
manifold,
Yes you could but it would be faster better and cheaper to build theYes, just design a system with multiple (not just dual) CPUs. Of course the system to manage the programs among all those chips is still going to be a bear to design. Jim |
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Re: clarification on my video and radio question
Himanshu Sharma
hey ,
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try and read RS485...that will help you have digital signal speed of about 2Mbps... and believe me Digital is easy and better when it comes to working with signals and you can control them easily...(synchronous and asynchronous...) Regards :-), --himanshu sharma ----- Original Message -----
From: <epsulon@...> To: <Electronics_101@...> Sent: Friday, November 02, 2001 12:07 AM Subject: [Electronics_101] clarification on my video and radio question : I want to make a complex robot. To keep it simple right now I just want the : robot to send video, temperature, and altitude. Maybe even some other things : later on. I was thinking I can go digital or analog. When would you use : digital or analog? I would think that analog would be easier because all the : sensors and video would be in analog. But yet isn't it true that digital : would be much simpler for manipulating the many signals? The easy part is : getting the sensors and video to work, and then sending their signals to : another device. Doesn't a multiplexor combine signals? Is there anything : else that combines signals that I might want to use? What I will send to the : robot will be control signals for servo's and such. : : I know I'm going to need to do studying to learn what I want to do. I just : finished reading two very basic electronics books. The books were Getting : Started in Electronics and Basic Electronics. Both are Radio Shack books. : What should I read now to help me reach the goal that I currently want to : achieve? : Lots of Thanks, : Jon : : : : : : : : : : : First of all keep in mind I'm a beginner. I would appreciate the groups help : in directing me for my project. This is something I have always wanted to : learn how to do. I think I want to make a carreer out of it. : : >From point A, I want to be able to take a video signal and other signals, : combine them into one, then send them out via radio. Then from point B : receive them, decode the signal, and use the video and other signals, for : whatever purposes I need. I also need to be able, from point B, to combine : other signals minus video this time, and send them via radio to point A, and : at point A decode those signals and use them. : : I can see many steps and components involved in getting this to work, and : would highly appreciate the groups help. : Thanks, : Jon : : |
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Re: CPU Question
Here is a link to the SciAm article -
- mark --- In Electronics_101@y..., "Daniel Imfeld" <dimfeld@h...> wrote: I read about a major company, I think it was HP, that has created aBeowulf cluster (a group of cheap PCs linked together to create asupercomputer) that qualifies as one of the more powerful supercomputers inexistence. One advantage of this method, they said, is that when you add and removelinearly, so it's easy to calculate how many computers you'll need for aspecific task. Also, it makes it easier to split the processing time between twoprojects if the need arises. I think they used something more powerful than486's and Pentiums, but I can't remember exactly what they used, as Iread about it a few months ago. I know that they used only cheap off-the-shelf PCs though. If I remember correctly, they run it on Linux, or somevariation of it, with a master computer (or computers) that controls all theothers, similar to Stanford's Folding@home project, but probably moreoptimized for LAN usage and proprietary things.although I imagine that it would take quite a bit of work to set everything up.The controlling software that would assign parts of the computing taskto variousbe better to just use thelots of energy and there'd berequirements, maybe some kindIt would certainly be amaking it happen in a |
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Re: CPU Question
Daniel Imfeld
I read about a major company, I think it was HP, that has created a Beowulf
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Show quoted text
cluster (a group of cheap PCs linked together to create a supercomputer) that qualifies as one of the more powerful supercomputers in existence. One advantage of this method, they said, is that when you add and remove computers from the cluster, the total processing power changes linearly, so it's easy to calculate how many computers you'll need for a specific task. Also, it makes it easier to split the processing time between two projects if the need arises. I think they used something more powerful than 486's and Pentiums, but I can't remember exactly what they used, as I read about it a few months ago. I know that they used only cheap off-the-shelf PCs though. If I remember correctly, they run it on Linux, or some variation of it, with a master computer (or computers) that controls all the others, similar to Stanford's Folding@home project, but probably more optimized for LAN usage and proprietary things. So I suppose if you do it correctly, you can get great results, although I imagine that it would take quite a bit of work to set everything up. Daniel Imfeld ----- Original Message -----
Saad, Old PC's can beI've heard about that but I wonder whether it is a practical idea. The controlling software that would assign parts of the computing task to various computers would have to be vary sophisticated. Then there would be the distances between computers. It would probably be better to just use the system cards otherwise all those old power supplies would consume lots of energy and there'd be the problem of varying power supply connectors and voltage requirements, maybe some kind of bus communication would be necessary to avoid port bottlenecks. It would certainly be a good project for some IT students but I think the work involved in making it happen in a real world situation would more than cancel most benefits. But then I could be wrong, wouldn't be the first or last time. Jim |
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Re: CPU question
Yes you could but it would be faster better and cheaper to build the
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super computer from faster CPU's. --- In Electronics_101@y..., Saad Rahman <saad_75@y...> wrote:
Well there is one more thing that can be done with old |
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Re: Parallel Port Interfacing
Are you considering designing an ASIC to communicate with the
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parallel port of a PC? snip %<-------------------- We are involved in BIDIRECTIONAL TRANSFER HERE. |
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Re: clarification on my video and radio questio n
Mounir Shita
¿ªÔÆÌåÓýNo, a
multiplexer doesn't combine signals. A multiplexer simple allows one signal to
pass while blocking another (simply said).For a complex robot like that, I would
most likely use digital transmission. Use some sort of high speed transmission
protocol. Maybe a LVDS ? You sending on RF or on cables ?
?
?
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clarification on my video and radio question
I want to make a complex robot. To keep it simple right now I just want the
robot to send video, temperature, and altitude. Maybe even some other things later on. I was thinking I can go digital or analog. When would you use digital or analog? I would think that analog would be easier because all the sensors and video would be in analog. But yet isn't it true that digital would be much simpler for manipulating the many signals? The easy part is getting the sensors and video to work, and then sending their signals to another device. Doesn't a multiplexor combine signals? Is there anything else that combines signals that I might want to use? What I will send to the robot will be control signals for servo's and such. I know I'm going to need to do studying to learn what I want to do. I just finished reading two very basic electronics books. The books were Getting Started in Electronics and Basic Electronics. Both are Radio Shack books. What should I read now to help me reach the goal that I currently want to achieve? Lots of Thanks, Jon First of all keep in mind I'm a beginner. I would appreciate the groups help in directing me for my project. This is something I have always wanted to learn how to do. I think I want to make a carreer out of it. From point A, I want to be able to take a video signal and other signals, combine them into one, then send them out via radio. Then from point B receive them, decode the signal, and use the video and other signals, for whatever purposes I need. I also need to be able, from point B, to combine other signals minus video this time, and send them via radio to point A, and at point A decode those signals and use them. I can see many steps and components involved in getting this to work, and would highly appreciate the groups help. Thanks, Jon |
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Re: clarification on my video and radio question
I want to make a complex robot. To keep it simple right now I just want the I have used a LM140 temperature sensor, whose output in 10 mV per degree Kelvin. ?I ran the output to a 10 bit A/D converter input on a PIC microcontroller. ?After scaling the data I then output it from the PIC to a PC via an RS-232 driver chip, a MAX232. ?This allows me to display temperature in Celsius on a PC. ?Similar temperature sensors are avilable whose outputs are scaled to degrees C or F. |
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Re: optoisolators
Doug Hale
Optical Isolators can be used for analog or audio signals.
You just have to understand the charactoristics of the device you are going to use. A photodiode/ phototransistor pair functions much like a four terminal transistor - like having a seperate curcuit for the base current - not common with the emitter. All you have to do is bias the photodiode so that the phototransistor is operating in the center of its linear region. Doug Hale |
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Re: 555 Observation
Jim Purcell
verhap,
In my class today, I hooked a 555 in astable mode to an o'scope.Did you have the scope in DC mode. If it was in AC mode the input capacitor might DC shift the voltage. That's. what the capacitor does, it removes the DC component and 'averages' the output. It's also a good idea to pay close attention to the voltage settings, you can learn a lot from them. Before connecting the signal position the trace on a convenient gratical (grid line). In the DC mode the output should only rise in the positive direction from that zero base line. In the AC mode a square wave should swing half above and half below that line. Jim |
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Re: 555 Observation
Curtis Sakima
Just Catching up on my old email reading so someone
may have answered already .... Yeah ... what happening is the the oscilloscope is probably set to "AC" coupled instead of "DC" coupled input. It's a switch... usually near the vertical volts per division switch. In "AC" mode, the scope tries to remove the DC component out of the waveform. And because the 555 output is from 0 to Vcc, the average (DC component) is 1/2 of Vcc. Hope this helps!! Curtis --- verhap@... wrote: In my class today, I hooked a 555 in astable mode to ===== * * * * Your website deserves a taste of rush hour traffic * * * * * * __________________________________________________ Do You Yahoo!? Make a great connection at Yahoo! Personals. |
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