RPM Meter
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From: Grant on 29 Jul 2010 23:38 On Fri, 30 Jul 2010 10:14:56 +1000, David Eather <eather(a)tpg.com.au> wrote: >On 30/07/2010 9:59 AM, John Larkin wrote: >> On Fri, 30 Jul 2010 09:27:40 +1000, David Eather<eather(a)tpg.com.au> >> wrote: >> >>> On 30/07/2010 9:14 AM, David Eather wrote: >>>> On 29/07/2010 9:55 PM, Jan Panteltje wrote: >>>>> On a sunny day (Thu, 29 Jul 2010 09:48:04 +1000) it happened David Eather >>>>> <eather(a)tpg.com.au> wrote >>>>> in<OoydnecLgt0rXM3RnZ2dnUVZ_gKdnZ2d(a)giganews.com>: >>>>> >>>>>> On 28/07/2010 9:09 PM, Jan Panteltje wrote: >>>>>>> On a sunny day (Wed, 28 Jul 2010 12:08:10 +1000) it happened David >>>>>>> Eather >>>>>>> <eather(a)tpg.com.au> wrote >>>>>>> in<RuidnQS0OouWDNLRnZ2dnUVZ_t2dnZ2d(a)giganews.com>: >>>>>>> >>>>>>> >>>>>>>> PIC? Shouldn't you use something like a 555 and an analogue meter? >>>>>>> NO >>>>>> >>>>>> But a 555 is the highest example of the chip designer's art. >>>>> >>>>> It sure is a clever chip, and you can make stable oscillators with it >>>>> with a frequency that does not depend on the supply voltage much. >>>>> However, in this case, if you generate a fast duration pulse to drive >>>>> an analog meter, you still need a voltage stabiliser, as you need a >>>>> constant amplitude. >>>>> >>>>> The PIC driving a LCD however, has an internal oscillator that has an >>>>> accuracy of >>>>> +-2% from 0°C to 85°C, and +-5% from -40°C to +125°C, this no longer >>>>> needs the regulator, >>>>> other then a simple zener perhaps to make 5 or 3.3 V, and no >>>>> calibration needed. >>>>> Better display possibilities, added calculation possibility for other >>>>> things, >>>>> like long time average, possibility of setting alarms, possibility of >>>>> loop control. >>>>> All in one PIC chip mind you. >>>>> >>>>> >>>>> >>>>> >>>>> >>>>> >>>> >>>> But the cost of the time to program it outweighs the cost of a voltage >>>> regulator. >>>> >>>> I am not actually a big fan of 555's - I just like how some "features" >>>> (like the switching generated power spikes) annoy some peoples. >>> >>> But seriously for a simple and temporary RPM meter without a chance to >>> act "funky" I would have put some form of one-shot and an analogue meter >>> as the ideal solution (fast, simple, cheap, little circuit/firmware >>> debugging). It's not without possible problems, but whatever they are >>> are very unlikely to be related to the problems in the original device. >> >> You could use my world-famous double-tach circuit... >> >> ftp://jjlarkin.lmi.net/DoubleTach.jpg >> >> John >> >> > >Actually I can't. I have never been able to view or download anything >posted at ftp://jjlarkin.lmi.net Look at your ftp or firewall settings, works fine here on Win7 with Google Chrome browser, and on Slackware with wget. Check for passive FTP enabled? Grant.
From: Grant on 30 Jul 2010 01:15 On Thu, 29 Jul 2010 20:06:55 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >On Thu, 29 Jul 2010 18:30:04 -0700, Rich the Cynic <cynic(a)example.net> >wrote: > >>On Wed, 28 Jul 2010 16:36:00 +0100, markp wrote: >>> >>>> John "The Bloviator" Larkin's post is a slap-it-on-paper-quick without >>>> thinking "solution". Use at your peril. He'll never label it with >>>> values. If he did, his "solution" could be checked. >>> >>> I rest my case. >> >>I guess he has to go after John since he's plonked practically everyone >>else on the group, presumably to "punish" us. (Ha, ha, I can't hear you, >>nanner nanner nanner!) ;-) >> > >Right. He only distributes technical excellence now in private emails, >because we village idiots don't deserve such wisdom. Darn, I was >hoping for further adventures in rusty patio furniture. Thing is, being reminded of a topology that may suit a particular case or problem is a valuable reply, doesn't take much time or effort to post, one gets from paper to camera to web site fairly easily these days. Even I can do it ;) I like ideas, reminders. If I wanted worked design solutions I'd be using text books, application notes and never be reminded of other ways to view a problem. Like that recent issue I had with ground noise, only two suggestions posted, neither worked on its own, but both in tandem worked. I was reminded one could put some impedance in the ground lead, I'd seen that done before, but forgotten the technique for that case. Out of 31 different IPs viewed the page one person (I think) made a couple suggestions that worked in tandem. Whatever fun there is in a flameful reply and/or the occasional flamefest is lost if it drags on for weeks, or starts becoming personal attack. Ideas can be silly, doesn't mean the person is (well, not all the time :) Grant.
From: Jan Panteltje on 30 Jul 2010 08:09 On a sunny day (Fri, 30 Jul 2010 09:14:03 +1000) it happened David Eather <eather(a)tpg.com.au> wrote in <vJGdne-9K6uils_RnZ2dnUVZ_ridnZ2d(a)giganews.com>: >On 29/07/2010 9:55 PM, Jan Panteltje wrote: >> On a sunny day (Thu, 29 Jul 2010 09:48:04 +1000) it happened David Eather >> <eather(a)tpg.com.au> wrote in<OoydnecLgt0rXM3RnZ2dnUVZ_gKdnZ2d(a)giganews.com>: >> >>> On 28/07/2010 9:09 PM, Jan Panteltje wrote: >>>> On a sunny day (Wed, 28 Jul 2010 12:08:10 +1000) it happened David Eather >>>> <eather(a)tpg.com.au> wrote in<RuidnQS0OouWDNLRnZ2dnUVZ_t2dnZ2d(a)giganews.com>: >>>> >>>> >>>>> PIC? Shouldn't you use something like a 555 and an analogue meter? >>>> NO >>> >>> But a 555 is the highest example of the chip designer's art. >> >> It sure is a clever chip, and you can make stable oscillators with it >> with a frequency that does not depend on the supply voltage much. >> However, in this case, if you generate a fast duration pulse to drive >> an analog meter, you still need a voltage stabiliser, as you need a constant amplitude. >> >> The PIC driving a LCD however, has an internal oscillator that has an accuracy of >> +-2% from 0�C to 85�C, and +-5% from -40�C to +125�C, this no longer needs the regulator, >> other then a simple zener perhaps to make 5 or 3.3 V, and no calibration needed. >> Better display possibilities, added calculation possibility for other things, >> like long time average, possibility of setting alarms, possibility of loop control. >> All in one PIC chip mind you. >> >> >> >> >> >> > >But the cost of the time to program it outweighs the cost of a voltage >regulator. Thats is true, as this seems to be a one time thing, in large quantities it would be the other way around, a calibration step costs money. But even for a one time thing, how much time will you spend looking at that speedometer wondering: 'How much is my average speed, what distance did I travel, what was my maximum speed, did I, or do I, break the speed limit', and maybe even estimated time of arrival? Can all be done with a PIC and LCD, and a couple of push buttons. The real time clock is a bonus that comes free. Couple of evenings coding :-) Better then some TV. >I am not actually a big fan of 555's - I just like how some "features" >(like the switching generated power spikes) annoy some peoples. Oh well I have a little PCB with a 555 on the desk now as RC a servo tester. It also has a 78L05 regulator. But I also did a servo controller with a PIC, more features, many more :-) http://panteltje.com/panteltje/pic/camc_pic/
From: Jim Thompson on 30 Jul 2010 10:55 On Fri, 30 Jul 2010 15:15:11 +1000, Grant <omg(a)grrr.id.au> wrote: >On Thu, 29 Jul 2010 20:06:55 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Thu, 29 Jul 2010 18:30:04 -0700, Rich the Cynic <cynic(a)example.net> >>wrote: >> >>>On Wed, 28 Jul 2010 16:36:00 +0100, markp wrote: >>>> >>>>> John "The Bloviator" Larkin's post is a slap-it-on-paper-quick without >>>>> thinking "solution". Use at your peril. He'll never label it with >>>>> values. If he did, his "solution" could be checked. >>>> >>>> I rest my case. >>> >>>I guess he has to go after John since he's plonked practically everyone >>>else on the group, presumably to "punish" us. (Ha, ha, I can't hear you, >>>nanner nanner nanner!) ;-) >>> >> >>Right. He only distributes technical excellence now in private emails, >>because we village idiots don't deserve such wisdom. Darn, I was >>hoping for further adventures in rusty patio furniture. > >Thing is, being reminded of a topology that may suit a particular >case or problem is a valuable reply, doesn't take much time or >effort to post, one gets from paper to camera to web site fairly >easily these days. Even I can do it ;) > >I like ideas, reminders. If I wanted worked design solutions I'd be >using text books, application notes and never be reminded of other >ways to view a problem. Like that recent issue I had with ground >noise, only two suggestions posted, neither worked on its own, but >both in tandem worked. > >I was reminded one could put some impedance in the ground lead, I'd >seen that done before, but forgotten the technique for that case. > >Out of 31 different IPs viewed the page one person (I think) made >a couple suggestions that worked in tandem. > > >Whatever fun there is in a flameful reply and/or the occasional >flamefest is lost if it drags on for weeks, or starts becoming >personal attack. Ideas can be silly, doesn't mean the person is >(well, not all the time :) > >Grant. And don't forget: CHARGE IS CONSERVED :-) ...Jim Thompson -- | James E.Thompson, CTO | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona 85048 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at http://www.analog-innovations.com | 1962 | Spice is like a sports car... Performance only as good as the person behind the wheel.
From: John Larkin on 30 Jul 2010 12:14
On Fri, 30 Jul 2010 15:15:11 +1000, Grant <omg(a)grrr.id.au> wrote: >On Thu, 29 Jul 2010 20:06:55 -0700, John Larkin <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >>On Thu, 29 Jul 2010 18:30:04 -0700, Rich the Cynic <cynic(a)example.net> >>wrote: >> >>>On Wed, 28 Jul 2010 16:36:00 +0100, markp wrote: >>>> >>>>> John "The Bloviator" Larkin's post is a slap-it-on-paper-quick without >>>>> thinking "solution". Use at your peril. He'll never label it with >>>>> values. If he did, his "solution" could be checked. >>>> >>>> I rest my case. >>> >>>I guess he has to go after John since he's plonked practically everyone >>>else on the group, presumably to "punish" us. (Ha, ha, I can't hear you, >>>nanner nanner nanner!) ;-) >>> >> >>Right. He only distributes technical excellence now in private emails, >>because we village idiots don't deserve such wisdom. Darn, I was >>hoping for further adventures in rusty patio furniture. > >Thing is, being reminded of a topology that may suit a particular >case or problem is a valuable reply, doesn't take much time or >effort to post, one gets from paper to camera to web site fairly >easily these days. Even I can do it ;) Circuit topologies are fun all on their own, and are appropriate as a starting point for discussion of an underspecified problem, like the ones we usually get here. Circuits are sort of like improv comedy, or jazz, or slam poetry. The one we had on current limiters was fun [1] I don't use Spice much, so I start with circuits without values and "simulate" them in my head. I visualize the way I'd want the circuit to work with correct but in fact unknown values, and if it looks interesting, real values could be plugged in later (one at a time even!) to force the dynamics to align with the image. [2] People who "visualize" a circuit's operation in Spice have no choice but to use real component values and then fiddle for results. I do admit to limited expertise with rusty patio furniture. >Whatever fun there is in a flameful reply and/or the occasional >flamefest is lost if it drags on for weeks, or starts becoming >personal attack. Ideas can be silly, doesn't mean the person is >(well, not all the time :) I like to drift "off topic" by injecting technical asides into the henpecky personal rants. But that makes some of the hens even madder. John [1] I *still* need a good, small, low-drop current limiter for use as a self-resetting fuse. The ideal part would be a SOT-23 whose current limit is set by one resistor, thermal limits, and retries at full current once in a while. How come nobody makes one, at least past 5 volts? Polyfuses sort of suck. [2] Suppose you had a Spice model that worked just right, but the values were hidden. Based on the waveforms, you could determine the actual parts values, one at a time, in any order. That's sort of the idea: visualize the circuit and the waveforms, then start poking in values. Sort of the anti-Spice. |