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How can I measure the speed of a moving vehicle from within?

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ASIC

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Speed measurement

How can I measure the speed of a moving vehicle (from within the vehicle) without putting sensors on the wheels, and not hooking into the car's computer system?

All suggestions velcome... even the odd ones!

ASIC
 

Re: Speed measurement

I even done a bicycle speed meter.
use a photo sensor in wheel,when whell rolling,sensor can send pulse signal,you only use a frequency to meter it.
 

Speed measurement

I am just thinking aloud here... What happens if the vehicle was a huge trunk and the wheels got dirty?


ASIC
 

Re: Speed measurement

How about a doppler ultrasonic system pointing at the road?
 

Re: Speed measurement

Hi,

Have you considered using a GPS receiver? It works pretty well measuring speed. However, this approach has some drawbacks: GSPs would have some troubles in urban canyons, under a thick forest or inside buildings.
 

Re: Speed measurement

There are very strong Rare Earth NdFeB magnets - one magnet (1 cm diameter) can hold 50 kg.

https://www.amazingmagnets.com/

I was buying there - two of these magnets exploded in my hands when one was jumping to other from 20 - 30 cm distance.

You can glue such magnet to side of your weel, and read its moving by the coil on chassis.
 

Speed measurement

the only working solution is doppler microwave radar.
It is easyer than you can imagine, you only need a CW source and a receiving antenna ( cone for example ). Adding source and received signal will give you a frequency in the Hz..kHz domain: easy to manage.
http://hyperphysics.phy-astr.gsu.edu/hbase/sound/radar.html
 

Speed measurement

- Use axis meter to measure acceleration and calculate speed .
- Measure wheel vibration and get the speed
- Use optical method (laser to road )
- Air flow meter (depends on environment wind)
 

Speed measurement

Doppler microwave radar sounds interesting. I will look at that. Could the radar penetrate i.e. the bottom of the car, if I decided to put it in the car cabin?


ASIC
 

Re: Speed measurement

ASIC said:
Doppler microwave radar sounds interesting. I will look at that. Could the radar penetrate i.e. the bottom of the car, if I decided to put it in the car cabin?


ASIC
Click to expand...

Usually microwaves does not penetrate metals. But if the bottom of your car is made of teflon, maybe it will.

/pisoiu
 

Re: Speed measurement

ASIC said:
How can I measure the speed of a moving vehicle (from within the vehicle) without putting sensors on the wheels, and not hooking into the car's computer system?
Click to expand...

Hi,

How about taking a look at some police equipment :)

Cheers !
 

Re: Speed measurement

Forget about CW radar,it should point at a certain angle to the road (a narrow beam antenna is needed);the road is not a good radar wave scatterer;the complexity is an issue,too.
If you want an odd idea:
A microphone,when "blown by the wind",creates a noise-like output signal whose voltage is proportional to the wind speed.Drawback:if there is an adverse or a fair wind,the accuracy will be compromised.
 

Re: Speed measurement

but i think the microwave doppler radar is expensive,use the UWB radar is more cheap!
 

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