Speed-limit Alert PLEASE HELP!!!!!!!!

[ante1]

Hi Pieter,

Yes I could see he was teasing you but my point was the problem of using the engine rpm for this purpose. The two links you provided are interesting and useful but I think maybe these types of sensors are too sensitive to work under your car. They will be exposed to all kinds of dirt and moist from the car itself and from the road. I would use an inductive sensor and a small piece of metal (or a number of like a cog, if more pulses are required) attached to the shaft. Inductive sensors are better suited to “live” in this environment. 8)
Just a suggestion.

 

[pieterw0]

Ante

You got me very interested in your suggestion. The small piece of metal, is this attached to the shaft with the inductor a few inches away?

Could you give more info as far as the specs of the inductive sensor. Perhaps if you have something on this type of configuration I would be happy to try it.

Thanks
Pieter

 

[audioguru2]

You could slow the circuit's response time by increasing the value of the 1uF capacitor at pin 4 of the LM2917.

 

[ante1]

Hi Pieter,

Yes but not as far away as a few inches, more like a few millimetres! Somethin like this is what’s needed:  http://www.elfa.se/elfa-bin/dyndok.pl?dok=7293.htm
This is just an example, there are many similar out there!

 

[pieterw0]

Audioguru

I am still on the old circuit. (Original)

Pieter

 

[pieterw0]

Thanks for the feedback tnk2k and Ante

I will scratch around a bit and see what I can come up with.

Pieter

 

[audioguru2]

You can slow down the response time of the original circuit by using two 10k resistors in series for R18 and adding a capacitor to ground at their junction. Try 100uF to 1000uF. ;D

 

[pieterw0]

Thanks! ;D

 

[MP1]

Pieter,
I suggest you continue to try contacting the author. I have e-mailed him a number of times and have had no problem with replies after a few days. Perhaps he is on holiday. In a past conversation, Red has told me all of the projects he posts on his site have been bench tested.

MP

 

[pieterw0]

Hi MP
Thanks for the advise

I got it working in a way.

Pieter

 

[Mandavar]

Hi all
Anyone here can help me with the operation of IC3 (Dual Monostable multi vib)
i really need to understand the full operation of this IC in the Wirless Speed Limit alert circuit ... Thanks for help in advance

 

[audioguru2]

Hi Mandavar,
Welcome to our forum. ;D
A good place to find out about an IC is from its datasheet:
http://www.datasheetarchive.com/datasheet.php?article=1131154

 

[Mandavar]

Hi Audiogurur
First of all thanks for ur greeting 
I tried to read the data sheet but for sorry it didnt help me i still cant understand how we can use this IC3 in such a operation...
Is it possible to help me with the operation of IC3A and IC3b and the realation between them and the exernal connections... i really want to understand this....

 

[Mandavar]

Hi Audiogurur
I have another question about the circuit u implemented using LM2917 (14 pin) ..
What if i want to use 9v (PP3 battery) the orginal one in the circuit? Do i need to change anything? If so plz can u help with this......
Thanks in advance for ur help
have a nice day

 

[audioguru2]

Hi Mandavar,
The LM2917 has a built-in 7.6V zener diode regulator. A 9V battery quickly drops to 7.2V which is too low then slowly drops to 6V which is much too low. Some of the pins need the regulated voltage. If a low-dropout 5V regulator is added then the voltage might be too low for the IC.

 

[Mandavar]

Hi Audioguru
Thanks for your help again
Actually i`m in need of your help again i hope i`m nt dist. you 
The first one about R8 What effect does this resistor for the signal when changing its value?
The second and the last one about the Inverters (IC2) Why two of them connected in series (IC2b+IC2c) While the other three (IC2d+IC2F+IC2E) Connected in parallel?
Thanks for your help
Have a nice day

 

[audioguru2]

The first one about R8 What effect does this resistor for the signal when changing its value?

The DC output voltage of the inverter that feeds R8 is a little high, so reducing the value of R8 reduces its DC voltage which makes the inverters following it operate at their most sensitive voltage, and the LED will turn off if there is no signal.

The second and the last one about the Inverters (IC2) Why two of them connected in series (IC2b+IC2c) While the other three (IC2d+IC2F+IC2E) Connected in parallel?

The series inverters are biased so that they are linear amplifiers. The third one amplifies the output of the second one and the second one amplifies the output of the first one for very high voltage gain.

A Cmos inverter has a low output current. Three in parallel have 3 times as much output current as one so they can supply enough current to light the LED, and still have enough output voltage to drive IC3.

 

[Mandavar]

Hi Audioguru
I really want to thank you for your help again
i really wonder if i can use a Buzzer in the load section so i can get a sound when the Input frequency is larger or equal to (1/2RC) and i need your suggestion about this if its possible...

Another question about the (1000MicroF  and 470 MicroF) Capacitors, why we are using this Values and why is attached in that postions the same question goes for the two Resistors Connected between pin[9 10 12]

I`m really sorry for the amount of questions but i`m really willing to know and understand everything in this circuit becaues i`m intrested in it.

Thanks for being so helpfull its so nice to get help from a kind person like you

 

[audioguru2]

i really wonder if i can use a Buzzer in the load section so i can get a sound when the Input frequency is larger or equal to (1/2RC)

The datasheet says the LM2917 can drive a load with up to 50mA.

Another question about the (1000MicroF

 

[Mandavar]

Hi Audioguru
The Capacitors are shown in the circuit u implemented using LM2917
Check the Attachment the capacitors are shown below