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2006-01-10 by Tim Mitchell
AVR-Chat@yahoogroups.com wrote: > One thing that has always bothered me about electronic > weather station > design: > > > How do you normalizee temperarture readings (perhaps I am > using the > wrong term here).? > Proper weather people have their temperature sensors in a thing
2006-01-10 by Tim Mitchell
AVR-Chat@yahoogroups.com wrote: > Hi all, > > I've been lurking for a while and have a question. > > I have bought a STK500 and wish to program it/monitor it with my > laptop. Only problem is that the laptop only has USB ports. I've > looked on the group to find mention of USB>pa
2006-01-10 by Kong
iiuc, this problem is not particular to electronic outdoor temperature sensing. the same can be said about mecury thermometer placed outdoor. electronics only bring the readings indoor and perhaps into a pc, then even on to the internet. also, sometime it's not only the absolute
2006-01-10 by Thomas Keller
Robert Adsett wrote: >At 11:18 PM 1/8/06 +0530, Anurag Chugh wrote: > > >>|why only PWM?.. why not use an R2R ladder instead with precision resistors... >>|i know they would hog a whole PORT but arent they easier to implement ?? >>|and they can do DC output values too... a simple
2006-01-10 by Kong
--- In AVR-Chat@yahoogroups.com, Ralph Hilton wrote: > http://www.prllc.com/productcart/pc/viewPrd.asp?idcategory=6&idproduct=12 > > Chapter 5, Project Development > This chapter focuses on the orderly development of a project using microcontrollers. A > complete wireless indoor/
2006-01-10 by Thomas Keller
Randy Ledyard wrote: > No argument with your facts there, but have you looked at Futurlec > (www.futurlec.com ) ? > They list 1% metal film resistors for $0.20/10 - or 2cents each - the > only problem with them is they take a long time to ship - from AUS or > HongKong - not sure
2006-01-10 by Ralph Hilton
On Mon, 09 Jan 2006 16:48:24 -0000 you wrote: > >tom, > >i'm half way to being converted! by nothing more than the quality of >your post alone! ;-) > >the last time i wrote anything substantial (>10 years ago), i went for >delphi instead of VB or VC++, does that make me a PIC or
2006-01-10 by gouy yann
hi all, if I correctly remember, to known the global error from the individual errors is somehow like computing the derivative of a function. where A and B are transfert functions with dA and dB their respective error. d(A+B) = dA + dB d(A-B) = dA + dB (always the worst case) d(A
2006-01-10 by Micah Stevens
Alright, I think me and my big mouth got schooled on this one. Thanks for the insight. -Micah On Monday 09 January 2006 10:50 pm, Roy E. Burrage wrote: > It actually is a divider, Micah. Each leg of the R2R ladder divides the > output current by 2. > > > REB > > Micah Stevens wro
2006-01-10 by Roy E. Burrage
It actually is a divider, Micah. Each leg of the R2R ladder divides the output current by 2. REB Micah Stevens wrote: Why? This isn't a divider circuit. I think I see what you're getting at, but I'm not sure I'm buying it. -Micah On Monday 09 January 2006 1:57 pm, Jim Wagner wrot
2006-01-10 by Robert Adsett
At 11:18 PM 1/8/06 +0530, Anurag Chugh wrote: >why only PWM?.. why not use an R2R ladder instead with precision resistors... >i know they would hog a whole PORT but arent they easier to implement ?? >and they can do DC output values too... a simple opam in front (voltage >followe
2006-01-10 by Randy Ledyard
Hey Tom No argument with your facts there, but have you looked at Futurlec ( www.futurlec.com ) ? They list 1% metal film resistors for $0.20/10 - or 2cents each - the only problem with them is they take a long time to ship - from AUS or HongKong - not sure -----Original Message-
2006-01-10 by Kong
--- In AVR-Chat@yahoogroups.com, Thomas Keller wrote: > In an older issue of Circuit Cellar, Ink, there is a feature on > building your own ultrasonic anemometer. thanks again tom. found it as a featured article. there's also a wireless weather station based on pic16f873... http:
2006-01-10 by kholt@sonic.net
For my scope testpoints, in my data paths, I always leave 6pin headers for a simple D-A, based on only 6 resistors: 1R,2R,4R,8R,16R,32R. R's are 1% values, multiples usually of 2.048K or another standard value. Standard 1% values are not always spot-on the power-of-2 value, howev
2006-01-10 by Johnathan Corgan
Micah Stevens wrote: > If you have 10, 100 ohm resistors in series, and each is 1% tolarance, the > tolarance of the total group is +- 10%.. That is indeed correct, and if each > is +-10%, then the total tolerance is +-100%.. odd as it may sound. Uh, no. Ten, 100 ohm, 10% toleran
2006-01-09 by James Hatley
----- Original Message ----- From: "Kong" To: Sent: Monday, January 09, 2006 8:48 AM Subject: [AVR-Chat] Re: AVR weather station for newbie... > > tom, > > i'm half way to being converted! by nothing more than the quality of > your post alone! ;-) > > the last time i wrote anythi
2006-01-09 by Thomas Keller
Kong wrote: >hi all, > >foa, newbie here, so pls go easy, if you could ;-) >i'm looking at building a weather station. google tells me there are a >few out there based on PIC. someone suggested AVR atmega169 but i'm put >off by its mlf packaging. >i'll need adc, lcd, push buttons
2006-01-09 by Thomas Keller
Jim Wagner wrote: >Sorry, but wrong about the tolerance! > >Each successive leg has half the tolerance contribution of >the leg just above it in the ladder. With 1% resistors, the >over-all tolerance will be in the 3-4% range. > > > Quite right. My bad. >What may be more critical
2006-01-09 by Micah Stevens
Hi Dave, Hmm.. I might be a complete fool. I was working on a tube amplifier quite a while ago where this bit me in the arse because I was thinking percentages and was off by quite a bit of ohms, but your math is quite correct. Sorry about typing before thinking. -Micah On Monday
2006-01-09 by Dave Hylands
Hi Micah, > If you have 10, 100 ohm resistors in series, and each is 1% tolarance, the > tolarance of the total group is +- 10%.. That is indeed correct, and if each > is +-10%, then the total tolerance is +-100%.. odd as it may sound. I don't agree. Let's take the example, of 10
2006-01-09 by John Samperi
At 09:08 AM 10/01/2006, you wrote: >you can never know >which way the value will be off, or by what specific quantity. > > So, with 16 devices each specified to be within + or - 1%, the overall >tolerance of the network is plus or minus 16%. Which could be 0%...in theory of cours
2006-01-09 by Micah Stevens
Why? This isn't a divider circuit. I think I see what you're getting at, but I'm not sure I'm buying it. -Micah On Monday 09 January 2006 1:57 pm, Jim Wagner wrote: > Sorry, but wrong about the tolerance! > > Each successive leg has half the tolerance contribution of > the leg ju
2006-01-09 by Micah Stevens
If you have 10, 100 ohm resistors in series, and each is 1% tolarance, the tolarance of the total group is +- 10%.. That is indeed correct, and if each is +-10%, then the total tolerance is +-100%.. odd as it may sound. In this R2R circuit though, this is not a series circuit. Ho
2006-01-09 by gtbecker@rightime.com
> ... Each component contributes to the overall tolerance of the system... I have no doubt, but the tolerances simply add? What happens if, in this case of 16 resistors, one uses 10%-tolerance resistors? The sum exceeds 100%? Does the error of either LSB resistance contribute to
2006-01-09 by Thomas Keller
Tom Becker wrote: > > ... assume that each of these resistance elements is an individual 1% >tolerance resistor. Total overall tolerance of the R2R ladder is now 16%... >How do you arrive at that? > > Simple mathematics. The reason tht tolerances are specified as plus and minuse
2006-01-09 by Thomas Keller
Jim Wagner wrote: >Each has its place. >R-2R networks take much less filtering. Response speed is >faster. Parts count is higher and it may take parts with >some precision. >PWM is (often) low parts count UNLESS you try to >reconstruct signals that are too close to the PWM >repet
2006-01-09 by Tom Becker
> ... assume that each of these resistance elements is an individual 1% tolerance resistor. Total overall tolerance of the R2R ladder is now 16%... How do you arrive at that? Tom
2006-01-09 by Thomas Keller
Anurag Chugh wrote: why only PWM?.. why not use an R2R ladder instead with precision resistors... i know they would hog a whole PORT but arent they easier to implement ?? and they can do DC output values too... a simple opam in front (voltage follower) will boost current output t
2006-01-09 by Jim Wagner
Sorry, but wrong about the tolerance! Each successive leg has half the tolerance contribution of the leg just above it in the ladder. With 1% resistors, the over-all tolerance will be in the 3-4% range. What may be more critical is monotonicity, especially the step going from 0x7
2006-01-09 by Jim Wagner
Each has its place. R-2R networks take much less filtering. Response speed is faster. Parts count is higher and it may take parts with some precision. PWM is (often) low parts count UNLESS you try to reconstruct signals that are too close to the PWM repetition frequency. Then, yo
2006-01-09 by Thomas Keller
Kong wrote: >hi all, >foa, newbie here, so pls go easy, if you could ;-) >i'm looking at building a weather station. google tells me there are a >few out there based on PIC. someone suggested AVR atmega169 but i'm put >off by its mlf packaging. >i'll need adc, lcd, push buttons,
2006-01-09 by Kong
tom, i'm half way to being converted! by nothing more than the quality of your post alone! ;-) the last time i wrote anything substantial (>10 years ago), i went for delphi instead of VB or VC++, does that make me a PIC or an AVR person? now if, i say if, i decide to go with AVR.
2006-01-09 by Zack Widup
On Mon, 9 Jan 2006, Kong wrote: > > hi all, > > foa, newbie here, so pls go easy, if you could ;-) > i'm looking at building a weather station. google tells me there are a > few out there based on PIC. someone suggested AVR atmega169 but i'm put > off by its mlf packaging. > i'll
2006-01-09 by Kong
hi all, foa, newbie here, so pls go easy, if you could ;-) i'm looking at building a weather station. google tells me there are a few out there based on PIC. someone suggested AVR atmega169 but i'm put off by its mlf packaging. i'll need adc, lcd, push buttons, ram/flash to store
2006-01-08 by Russell Shaw
Anurag Chugh wrote: > why only PWM?.. why not use an R2R ladder instead with precision > resistors... > i know they would hog a whole PORT but arent they easier to implement ?? > and they can do DC output values too... a simple opam in front (voltage > follower) will boost curren
2006-01-08 by Anurag Chugh
why only PWM?.. why not use an R2R ladder instead with precision resistors... i know they would hog a whole PORT but arent they easier to implement ?? and they can do DC output values too... a simple opam in front (voltage follower) will boost current output too... i am sure most
2006-01-08 by James Washer
No problem.. I likely stated my questions poorly... i.e... I'm using PWM and a L.P filter to creat a DAC On Sat, 07 Jan 2006 21:39:58 -0600 Thomas Keller wrote: > Thomas Keller wrote: > > >>Below is my (limited) understanding of PWM DAC.. I'm just looking for comments regarding (
2006-01-08 by Thomas Keller
Thomas Keller wrote: >>Below is my (limited) understanding of PWM DAC.. I'm just looking for comments regarding (any) mistakes in my understanding. >> I am confused. Why wouldyou drive a DAC with PWM? If you're using a >>DAC, just output the digital value to the DSAC, either in p
2006-01-08 by Thomas Keller
James Washer wrote: >Below is my (limited) understanding of PWM DAC.. I'm just looking for comments regarding (any) mistakes in my understanding. > > I am confused. Why wouldyou drive a DAC with PWM? If you're using a DAC, just output the digital value to the DSAC, either in para
2006-01-07 by James Washer
Good point on the 8bit/12bit... thanks - jim On Sat, 07 Jan 2006 18:02:19 -0500 Robert Adsett wrote: > At 12:46 PM 1/7/06 -0800, James Washer wrote: > >Finally, I would assume one needs to worry about the "ratio" of R to > >C. If one chooses a LOW resistance and a large capacitan
2006-01-07 by Robert Adsett
At 12:46 PM 1/7/06 -0800, James Washer wrote: >Finally, I would assume one needs to worry about the "ratio" of R to >C. If one chooses a LOW resistance and a large capacitance, we might >still have a reasonable RC compared to the PWM frequency, however, we'll >also have large cur
2006-01-07 by Tom Becker
> ... I'm a beginner at all of this. One would never know; you have a good grasp. PWM DACs are based on averaging pulses to a corresponding equivilent voltage or current. The average is usually generated by using an RC, a simple filter that reduces high-frequency components, and
2006-01-07 by James Washer
Below is my (limited) understanding of PWM DAC.. I'm just looking for comments regarding (any) mistakes in my understanding. Assume we are driving the DAC with an AVR and the DAC's load has infinite impedance (i.e. opamp voltage follower or some such circuit) When using PWM to "c
2006-01-07 by Tom Becker
Dave VanHorn wrote: > Can anyone point me to data on using these in a pulsed discharge application? http://data.energizer.com/PDFs/cr2032.pdf
2006-01-06 by Dave VanHorn
Can anyone point me to data on using these in a pulsed discharge application? Specifically, I'm looking to power a T26L and other junk for 30mS at about 30mA.. I need to know how much "droop" to expect.
2006-01-05 by James Washer
Interesting article using AVR and FTDI to to GPIB->USB interface... http://www.edn.com/article/CA6290453.html?nid=2857&rid=1864395781
2006-01-05 by scmikes03
Good to know about the Grizzlies :-) I bought the combo from him before christmas - book - project supplies (the first time through, it is nice to use exactly what the book uses for the projects). - butterfly. The book is very good for people new to the AVR. I would recommend thi
2006-01-05 by John Samperi
G'day all As Mr Murphy says "there's always one more bug"! Andrey Hulap from the Ukraine pointed out a bug with V3.2 that prevented the programmer to go into page mode programming. Andrey if you read this my reply to you bounced. I have tested the fixed version with a M8 and a 17
2006-01-05 by John Samperi
At 12:24 PM 5/01/2006, you wrote: >Dear sir, > Can you please send me EBook of the same. > > >check out www.smileymicros.com . You can download a couple of chapters from the website, the rest you'll have to buy...with money. Dear ol Smiley is part of this list so he knows all abo
2006-01-05 by Dave VanHorn
--- In AVR-Chat@yahoogroups.com, "John Burton" wrote: > > check out www.smileymicros.com . I have just ordered the AVR butterfly > and his C programing book. It's pretty good, and it's hard to beat the GCC compiler that he gives a very painless intro to.