Digital Speedometer using discrete components and no use of microcontrollers

[samsin]

I am trying to build a warning speedometer that will be capable of driving an 8 ohm speaker and the speaker will sound at 60mph and the tone increases and interrupted 10mph thereafter. It must also show a the values in 2 seven segment display. In addition I cannot used programmable chips. Can anyone please help me in my senior design project. I am struggling to build and design it. Thank you.

 

[Gorgon]

Can you use logic ICs?

For example the 74hcxx or CD4xxx logic family?

What is the input signal looking like, frequency, range?

 

[betwixt]

You need something to produce pulses related to the speed, possibly something producing a signal once per revolution of a wheel.
Then you need an accurate timing circuit to open a gate for a predetermined period to allow the pulses to be counted within a known time period.
You can then relate pulses per period to speed in mph.
Then using binary comparators you compare the count digits with your 60/70/80 mph limits and operate your alarm as the numbers match.

It's much easier using a micro but the method of measurement is exactly the same if you do it with discrete logic devices.

An alternative but less acurate method is to use a frequency to voltage converter (maybe a charge pump circuit) to produce an analog voltage proportional to the speed then use voltage comparators to see if you have exceeded the speed thresholds.

Brian.

 

[colin55]

"Can anyone please help me in my senior design project. I am struggling to build and design it."

What happened in all the 3 years of doing the: "MASTERS OF ELECTRONICS" course?