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

[ASIC]

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

 

[alphi]

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.

 

[ASIC]

Speed measurement

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


ASIC

 

[flatulent]

Re: Speed measurement

How about a doppler ultrasonic system pointing at the road?

 

[gil]

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.

 

[klug]

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.

 

[mdamdam]

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

 

[artem]

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)

 

[ASIC]

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

 

[pisoiu]

Re: 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

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

/pisoiu

 

[nex]

Re: 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?

Hi,

How about taking a look at some police equipment

Cheers !

 

[batdin]

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.

 

[springf2000]

Re: Speed measurement

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