Date: 19/03/2014 10:17:31
From: transition
ID: 505518
Subject: Hands on the clock go around and around
How do you make a speedometer visually represent Kinetic Energy?
How do you make a speedometer visually represent Kinetic Energy?
transition said:
How do you make a speedometer visually represent Kinetic Energy?
check it against the tacho.
It will be a non linear scale, as energy is proportional to velocity squared.
So I need a scale representative the magic in V^2
The reality appears to be speedometers indicate little of this. What do you reckon is the answer?
Can I get rid of the reference to time somehow, you know delete the per hour thing.
I want a practical solution.
I suppose the mass of the vehicle could be known and the true KE be indicated, this of course wouldn’t be a speedometer, it’d be something else.
Of course the mass in this case would also be a variable. Number of passengers, fuel load, how much pot you’ve got stashed in the boogy board in the boot etc.
>Of course the mass in this case would also be a variable. Number of passengers, fuel load, how much pot you’ve got stashed in the boogy board in the boot etc.
True, indulge me though, just make it the maximum weight allowed of a loaded vehicle, give me some idea of how one might arrange an old analogue type speedo.
Point is to get rid of the reference to time, the per hour thing in KM/H, can it be done.
You could either go analog or digital. The analog approach would be to dismantle the speedo and replace the scale with something that indicated V^2.
But aren’t you a bit of an electronics buff? In that case I would think an Arduino with a suitable pickup and a fairly simple algorithm, outputting to a small screen would do the trick.
transition said:
>Of course the mass in this case would also be a variable. Number of passengers, fuel load, how much pot you’ve got stashed in the boogy board in the boot etc.True, indulge me though, just make it the maximum weight allowed of a loaded vehicle, give me some idea of how one might arrange an old analogue type speedo.
Point is to get rid of the reference to time, the per hour thing in KM/H, can it be done.
transition said:
>Of course the mass in this case would also be a variable. Number of passengers, fuel load, how much pot you’ve got stashed in the boogy board in the boot etc.True, indulge me though, just make it the maximum weight allowed of a loaded vehicle, give me some idea of how one might arrange an old analogue type speedo.
Point is to get rid of the reference to time, the per hour thing in KM/H, can it be done.
Hmm, surely it is just the intergral of the velocity.
>In that case I would think an Arduino with a suitable pickup and a fairly simple algorithm, outputting to a small screen would do the trick.
More thinking of ease of readability, what it means to the driver.
sibeen said:
transition said:
>Of course the mass in this case would also be a variable. Number of passengers, fuel load, how much pot you’ve got stashed in the boogy board in the boot etc.True, indulge me though, just make it the maximum weight allowed of a loaded vehicle, give me some idea of how one might arrange an old analogue type speedo.
Point is to get rid of the reference to time, the per hour thing in KM/H, can it be done.
Hmm, surely it is just the intergral of the velocity.
KE = (0.5)mv^2
The v part of the formula is distance divided by time.
Use a logarithmic scale on your analogue speedo. Simple.
morrie said:
sibeen said:
transition said:
>Of course the mass in this case would also be a variable. Number of passengers, fuel load, how much pot you’ve got stashed in the boogy board in the boot etc.True, indulge me though, just make it the maximum weight allowed of a loaded vehicle, give me some idea of how one might arrange an old analogue type speedo.
Point is to get rid of the reference to time, the per hour thing in KM/H, can it be done.
Hmm, surely it is just the intergral of the velocity.
wrt to what?
Well, true dat, time is inherent in the velocity :)
But knowing the velocity it is quite simple with an op amp or two to do an intergral and feed that to some form of meter.
sibeen said:
morrie said:
sibeen said:Hmm, surely it is just the intergral of the velocity.
wrt to what?Well, true dat, time is inherent in the velocity :)
But knowing the velocity it is quite simple with an op amp or two to do an intergral and feed that to some form of meter.
hint: begins with A
;)
morrie said:
sibeen said:
morrie said:wrt to what?
Well, true dat, time is inherent in the velocity :)
But knowing the velocity it is quite simple with an op amp or two to do an intergral and feed that to some form of meter.
and the integral of velocity wrt time is….?hint: begins with A
;)
morrie said:
morrie said:
sibeen said:Well, true dat, time is inherent in the velocity :)
But knowing the velocity it is quite simple with an op amp or two to do an intergral and feed that to some form of meter.
and the integral of velocity wrt time is….?hint: begins with A
;)
Or maybe D
-A
>KE = (0.5)mv^2
The v part of the formula is distance divided by time.
Use a logarithmic scale on your analogue speedo. Simple.
Yes my third neuron had got that far.
The KM/H though is like a human measurement construction, I was wondering if I could reference from KE and pretend it linear, use it as the reference.
transition said:
>KE = (0.5)mv^2
The v part of the formula is distance divided by time.
Use a logarithmic scale on your analogue speedo. Simple.Yes my third neuron had got that far.
The KM/H though is like a human measurement construction, I was wondering if I could reference from KE and pretend it linear, use it as the reference.
err…and KE isn’t a human measurement construction?
transition said:
>KE = (0.5)mv^2
The v part of the formula is distance divided by time.
Use a logarithmic scale on your analogue speedo. Simple.Yes my third neuron had got that far.
The KM/H though is like a human measurement construction, I was wondering if I could reference from KE and pretend it linear, use it as the reference.
transition said:
Well, no. You wanted an analogue speedo to show KE. Use a logarithmic scale on the speedo. You could build a new scale using a spreadsheet.
>KE = (0.5)mv^2
The v part of the formula is distance divided by time.
Use a logarithmic scale on your analogue speedo. Simple.Yes my third neuron had got that far.
The KM/H though is like a human measurement construction, I was wondering if I could reference from KE and pretend it linear, use it as the reference.
If you want a linear scale, that is non-trivial.
>err…and KE isn’t a human measurement construction?
Well, err, it’s a physical force the energy itself I suppose. Probably has to be relative to something else to be realized.
>I don’t think a logarithmic scale will work. I just tried to do a spread-sheet to show that, but I am growing tired and lazy. You need a scale that is proportional to v^2. Doesn’t matter what the mass of the vehicle is, the scale will be similar and in the proportion required.
I am having a play with the idea that much of reality appears conceived from time as linear, yet KE generates much of that reality and it’s not when referenced to time for velocity as we measure it.
Taking up the integration theme, I am thinking that you could integrate the acceleration.
Think of V^2 = U^2 + 0.5 aT
So, integrate a with time and you have v^2
An accelerometer, with an integrator.
Jebus, no more wine
Could have a braking distance indicator instead of a speedometer.
Ok, one last go.
Integrate the accelerometer wrt to the odometer.
V^2 = U^2 + 2aS
PM2Ring will slaughter me for all this.
transition said:
I really don’t understand the difficulty.
Could have a braking distance indicator instead of a speedometer.
The 10 on the speedo is some number proportional to 100.
The 20 on the speedo is some number proportional to 400.
The 30 on the speedo is some number proportional to 900.
The 40 on the speedo is some number proportional to 1600.
The 50 on the speedo is some number proportional to 2500.
etc.
Write those numbers on the speedo at the relevant places, and you display the KE.
The 10 on the speedo is some number proportional to 100.
Michael V said:
transition said:I really don’t understand the difficulty.
Could have a braking distance indicator instead of a speedometer.
The 10 on the speedo is some number proportional to 100.
The 20 on the speedo is some number proportional to 400.
The 30 on the speedo is some number proportional to 900.
The 40 on the speedo is some number proportional to 1600.
The 50 on the speedo is some number proportional to 2500.
etc.
Write those numbers on the speedo at the relevant places, and you display the KE.
>Write those numbers on the speedo at the relevant places, and you display the KE.
yeah got that far, now in terms of how it is perceived, spacings and all, colours perhaps.
a KE gauge / meter inside a car would be an excellent visual warning to drivers who think its ok to drive that ‘little bit’ faster …
>Not really. It is intimately connected with time.
Just out of interest, which way does this work, we derive KE from time, or derive time from phyical forces like KE.
transition said:
>Not really. It is intimately connected with time.Just out of interest, which way does this work, we derive KE from time, or derive time from phyical forces like KE.
morrie said:
transition said:
>Not really. It is intimately connected with time.Just out of interest, which way does this work, we derive KE from time, or derive time from phyical forces like KE.
Too deep for me.
My statement comes from the fact that I often scale kinetic and potential energy. In doing so, you also automatically scale the time domain. You can approach the whole issue of scaling of dynamic systems from the time domain point of view, though I don’t normally do that.
Ooo, we could do a FFT (fast fourier transform) and look at it in the frequency domain.
sibeen, never actually helping since 1998
:)