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Analogue is better for readings which are changing, such as speed in a car or altitude in a plane, but digital is better for a relatively constant reading such as a refrigerator temp display or gigabytes free on a hard disk.
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The typical analogue speedo is actually digital though.
Turn say a Ford unit into diagnostic mode and the speed is displayed in digital form which fluctuates a lot more than the analogue. They seem to have programmed some sort of intertia into the analogue dial. Oh and when entering the diag mode the needles on the speedo and rev counter all swing round so they are definately being fed signal electronically on what to display.
The digital readout is also a lot more accurate as speed increases.
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Analogue every time, the position of the needle gives a relative reading at a glance.
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Back in the day i absolutely loved my cousins MK2 Astra GTE with the digital dash.
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Back in the day i absolutely loved my cousins MK2 Astra GTE with the digital dash.
What blue_haddock said. :P
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Analogue every time the position of the needle gives a relative reading at a glance.
Again I would argue this with the Kwak example above. 60 and 80 look very similar and aren't that far apart on a 180mph speedo.
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5000 in a diesel would be banging off the limiter whereas a Honda S2000 would just be warming up. A rev counter is analogue so you can see where you are in relation to the operating range of the engine in that gear.
What about a percentage then?
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ISTR the Fiat Tipo had a digital speedo that had a row of bars above it - the numerals gave the exact speed, and the bars lit from left to right to indicate the position within the engine's range.
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Can we indicate our age with replies?
I'm ancient (pushing 60) and prefer analogue! But not those old dials that took a while to catch up, I can't remember their name, but I'm sure someone'l put me right!
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Chronometric!
You can actually buy pseudo chronometric tachometers at a vast price but why is another matter.
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ISTR the Fiat Tipo had a digital speedo that had a row of bars above it - the numerals gave the exact speed and the bars lit from left to right to indicate the position within the engine's range.
I'll put money on the fact the rev limiter intervened before the red or amber LED lit up...
Uno Mk1 turbo's had the option of LED dashboards. Guess which ones had turbo and cam belt problems ?
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The definitive answer is that analogue representations of quantity require less processing power from human resources than do digital representations, hence quicker perception.
The reason is simple: analogue representations do not reuiure Number. Number in the perceptual sense needs an extra translation or process to give a meaning. Analogue perceptions of quantity only require learning of a pattern, e.g. try this experiment: look at your watch. If it says for example '4:52' pm (digital face) your brain translates to says 'ah, 4,5,2 so nearly 5 to 5' or even 'nearly 5 to 5 or even nearly 5 o-clock'. On an analogue dial the nearly-ness of 5 o'clock immediately registers - no calculation of number is required, the familair pattern of the hands in that position is much quicker to recognise. We are programmed, by the evolutionary imperative, to recognise patterns & shapes more quickly.
Look at your rev. counter - how much more easy is it to recognise the position of say, 4,000 rpm from its position on the dial (nearly vertical for most petrol engines) or '2 p.m.' for most diesels in top gear.
I dislike representations of quantity in digital format (for real-time activities) for this reason.
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I agree totally with Woodbines, well said!
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Digital readouts are an 80s gimmick. Like digital watches, they should have been discontinued years ago.
If Citroen are still doing them, it doesn't say much for the confidence they have in their product. They should possibly put more effort into getting their electrics right in the first place before adding more gimmicks.
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I drive a Yaris with digital readout. For all but the illiterate, I'm sure it's much better. No peering, no recognising positions, just simple big clear nos in a shielded display .
You're just old stick in the muds: unable to adapt to changes.
:-)
madf
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Change for changes sake is rarely a good thing.
I prefer analogue ~ but modern electronic not old-fashioned mechanical.
--
L\'escargot.
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As Woodbines says,analogue will tell you quickly if you're doing approximately 30mph whilst digital will need a longer look to tell you if you're dodoing exactly 29 or 31 mph.
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Analogue enables one to easily observe a rate of change or a trend. When flying I used to have both head up digital and head down analogue. If you are in a descent and trying to level out at a particular height it is way easier to judge it by looking at the movement of a needle than the change of numbers in a digital display.
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From my only experience of digital in a Yaris the speedo takes time to catch up and show your actual speed.
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daveyjp, you're absolutely right. By definition any digital system must take a sample of the speed over a set period, and to be accurate this set period must be in the order of tens of milliseconds at least, in practice hundreds of milliseconds -- at 70mph the engine is only turning around 40rpm/mph so to get a sample accurate to within 1mph takes at very least 1.3 seconds.
Having said that, I doubt that a Yaris has such blistering acceleration that such accuracy is required, and in any case an analogue system is similarly sampled and hence just as inaccurate. I've noticed a similar lag with dial-based systems, it's just harder to detect.
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To get comfortably below 1mph resolution (assuming a wheel radius of 300mm and 30 teeth on the ABS pickup)
vmph=70; rwheel=0.3; vms=vmph*1.6093*1000/3600; omegaw=vms/rwheel; nteeth=30; omegasignal=omegaw*nteeth; fsignal=omegasignal/(2*pi)
fsignal =
498.0268
f_1mph=fsignal/70
f_1mph =
7.1147
t_sample=2/f_1mph
t_sample =
0.2811
So, about 0.3 seconds.
Number_Cruncher
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"If Citroen are still doing them"
I assume you're referring to the weird rotating drum dials fitted to some GS's and Mk.1 CX's that were described as digital, but were really analogue with bigger numbers. Once you got over the initial shock, they worked rather well, IMHO, as you got a big numerical indication of speed or revs with the analogue component of speed of variation. Probably not as good as a conventional dial with clear numbers, where the angle of the needle tells you most of what you need to know, but certainly better than electronic digits.
The clincher for me is that on my bike, which has identically sized dials close together, I can also tell at a glance what gear I'm in, simply from their relative positions...
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analogue representations of quantity require less processing power from human resources
Aaaah! That's why I prefer analogue. Fewer brain resources ...
Perhaps the same applies to preferring a slide-rule to a calculator.
Hawkeye
-------------------------------------
aged fify-five and three-quarters
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Buy an AUDI with DIS and the get the BEST OF BOTH WORLDS.
Traditional Analogue speedo & rev counter, with the user-delectable option to display digital speed in big numbers in the central fuel computer display. Great for driving on the continent (can easily switch to km/h).
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A Merc Vito I borrowed for an evening had a dual digital/analogue display - most distracting.
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A Merc Vito I borrowed for an evening had a dual digital/analogue display - most distracting.
How can a dual display be distracting?
If you're distracted by a number showing on the dash display, you really should stop driving immediately before you do some damage.
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Scenic had digital. Altea has analogue.
Prefer the Scenic as the Altea is in 20mpg increments and they are evens, so no marker for 30,50,70 which I think are the highest number of speed limits.
Having said that , SWMBO could see the Scenic speedo from the passenger seat, she can't see the Altea's!
--
2007 Seat Altea XL 2.0 TDI (140) Stylance
2005 Skoda Fabia vrS
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On a separate note, I read recently that the new Corsa is not allowed to be used for driving tests as the examiner is unable to see the speedo from the passenger seat. Thought that would be a big blow to Vauxhall as I see plenty of the older style Corsa's as Learner cars.
--
2007 Seat Altea XL 2.0 TDI (140) Stylance
2005 Skoda Fabia vrS
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What manufacturers should do is repalce the instrument display with a TFT display which has various preset displays (analogue, digital) and allow you to design your own layout (within limits - e.g you must have a speedometer and it must be a specific size).
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The Scenic is the first car I've owned with a digital display, and on balance I think I prefer analogue.
It's certainly true that with conventional dials you refer to needle position as much as the actual reading for a "quick glance" assessment of speed or revs. This is obviously impossible with digital. I didn't realise I did this until I lost the analogue dials.
The Scenic's central location of its display panel is also not ideal. It means diverting your eyes quite markedly from the road ahead, and the difference between say 30 and 38 is not always discernible in your peripheral vision as the position of a big needle would be. The Mondeo has two huge, beautifully clear dials for speed and revs, and these can be seen clearly out of the "corner of your eye" as it were. Oh, and having a display in the middle means it's also on full view to all your passengers which means you get the odd tut or comment if you're pressing on. The days of having mates in the car who would approve of illegal speeds with words of encouragement are sadly long gone! ;-)
What digital is good for is its absolute precision (within the limits of its accuracy of course). It's also nice if you drive on the continent, where of course you can flick to km/h and have a proper readout in "foreign" numbers. Much nicer than having to decipher that 6 point font that most speedos carry their km/h calibrations in, or do the conversions in your head. It's also neat having everything together in one place. The Scenic's single central panel carries speed, revs, fuel, temperature, all warning lights, fuel computer readout, radio/CD information and door ajar display. Keeps the rest of the dash nice and neat.
The Scenic's biggest problem is its rev counter which is completely useless. 1 illuminated segment = about 250 RPM.
--
04 Grand Scenic 1.9 dCi Dynamique
00 Mondeo 1.8TD LX
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I like analogue, especially when they're laid out so that 30mph is a horizonal needle, and 70mph is a vertical needle. Easy to see if you're breaking the speed limit without even looking at the numbers. Can be done from the corner of your eye too, unlike digits which need to be read.
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On a separate note I read recently that the new Corsa is not allowed to be used for driving tests as the examiner is unable to see the speedo from the passenger seat. Thought that would be a big blow to Vauxhall as I see plenty of the older style Corsa's as Learner cars.
If true, that's absolutely catastrophic for Vauxhall I'd have thought, seeing as the Corsa is the learner car, and BSM buy them up in huge numbers. It's as bad as if they'd lost Vectra reps sales -- Vauxhall would be sunk if they had to rely on private sales only.
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Maybe they should have told my wife when she passed in her new corsa about a month ago. Thge bigest problem was getting a stick on mirror for the examiner that stayed and fitted on the sloping windscreen .....
The DSA website says:
"Category B - cars and vans
Cars or vans presented for test must be:
a four wheeled vehicle of no more than 3500 kilograms (kg) maximum authorised mass (MAM)
capable of a speed of at least 100 kilometres per hour (km/h) or 62.5 miles per hour (mph)
The car or van must also be fitted with:
a seatbelt for the examiner
a passenger head restraint, this needn't be adjustable but must be fitted as an integral part of the seat - 'slip on' type head restraints aren't permitted
an interior mirror for the examiner's use
L-plates displayed on the front and rear of the vehicle but not interfering with the driver's or examiner's view
a speedometer that measures speed in miles per hour and kilometres per hour
The vehicle must be legal and roadworthy and have no warning lights showing ie the airbag warning light."
There are no notes on there about not being able to use a Corsa.
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...... preferring a slide-rule to a calculator.
Crikey Hawkeye, now that is what I'd call being old-fashioned! When did you dump your abacus and log tables?
--
L\'escargot.
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