A
Alun
- Jan 1, 1970
- 0
Good idea audioguru, could you replace IC1 and IC2 with a dual op-amp?
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audioguru2
- Apr 6, 2004
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Thanks, Alun. ;D
I think the 4 cascaded inverters will have a reasonable bandwidth and have much more gain over the bandwidth than an opamp. It is good to have the very low output impedance of the opamp as the 1st stage, to avoid positive feedback from the paralleled inverters output to the input of the 1st inverter.
Imagine how low-level the signal from the spark-plug cables would be when picked-up in the car's cabin. This circuit might even be able to pick-up a signal from another car beside you on the road! ;D
View attachment 37103
I think the 4 cascaded inverters will have a reasonable bandwidth and have much more gain over the bandwidth than an opamp. It is good to have the very low output impedance of the opamp as the 1st stage, to avoid positive feedback from the paralleled inverters output to the input of the 1st inverter.
Imagine how low-level the signal from the spark-plug cables would be when picked-up in the car's cabin. This circuit might even be able to pick-up a signal from another car beside you on the road! ;D
View attachment 37103
Hi Audioguru and guys.
Could you go back a few posts please! There is a few questions that I would like for you to answer, if it is not to much trouble.
To answer Dazza’s question.
I have a mechanical speedometer. This brings about a different topic. The application I want is a unit that if I preset it to 60mph then it must switch the buzzer and LED on at that point. So in other words all above 60mph this unit must moan until I reduce speed below 60mph. Once below 60mph the warnings must stop. This is actually all I need. The Speed limit alert circuit on the website doesn’t work so I’m looking at alternatives.
BUT
As far as I know the tachometer is the only way to go as far as wireless is concerned. Once you go the speedometer way you need a fixture like a shaft that you can count the number of revolutions per minute.
This will be to expensive.
I would rather settle for a small inexpensive way to warn me of over speeding. (Something I am guilty of many times)
Audioguru
You spoke about the 4 cascaded inverters. IC1 and IC2 is not that hot. Not to forget. IC3a also has some amplification. You must move the unit back and forth and sideways in the cabin to get a proper signal. The signal I found was basically next to the wind screen. (Not a good position) The LM2917 also has some amplification in the first of it’s three parts.
If you think that the 4 cascaded inverters discussed with Alum, will work better I would rather go for that.
Give me the schematic for a decent Speed alert with a buzzer and LED warning and I will build it.
Just for interest sake:
I have rebuilt the L1, IC1 and IC2 section again. If pin 4 of IC1 is connected D1 stays lit and doesn’t pick up a signal. Once disconnected D1 goes out. It starts flashing when a signal is detected.
Pieter
Could you go back a few posts please! There is a few questions that I would like for you to answer, if it is not to much trouble.
To answer Dazza’s question.
I have a mechanical speedometer. This brings about a different topic. The application I want is a unit that if I preset it to 60mph then it must switch the buzzer and LED on at that point. So in other words all above 60mph this unit must moan until I reduce speed below 60mph. Once below 60mph the warnings must stop. This is actually all I need. The Speed limit alert circuit on the website doesn’t work so I’m looking at alternatives.
BUT
As far as I know the tachometer is the only way to go as far as wireless is concerned. Once you go the speedometer way you need a fixture like a shaft that you can count the number of revolutions per minute.
This will be to expensive.
I would rather settle for a small inexpensive way to warn me of over speeding. (Something I am guilty of many times)
Audioguru
You spoke about the 4 cascaded inverters. IC1 and IC2 is not that hot. Not to forget. IC3a also has some amplification. You must move the unit back and forth and sideways in the cabin to get a proper signal. The signal I found was basically next to the wind screen. (Not a good position) The LM2917 also has some amplification in the first of it’s three parts.
If you think that the 4 cascaded inverters discussed with Alum, will work better I would rather go for that.
Give me the schematic for a decent Speed alert with a buzzer and LED warning and I will build it.
Just for interest sake:
I have rebuilt the L1, IC1 and IC2 section again. If pin 4 of IC1 is connected D1 stays lit and doesn’t pick up a signal. Once disconnected D1 goes out. It starts flashing when a signal is detected.
Pieter
Hi Audioguru and guys.
My humblest apologies to every one on the forum !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I found out by accident that with pin 4 on IC1 connected works.
The fact of the matter is that my computer is on the work bench. Having said this the magnetic pulses generated by the computer screen caused D1 to light. No matter in whatever position you turn R8 the led stayed lit. This was also the reason that the buzzer went beep on a per second basis. My computer hanged and I had to switch it off. Only when I did this I noticed that the led had gone dead. After restarting I moved away from the computer. The further away I moved the dimmer it got. So for about 2m + D1 goes out completely.
To give you an indication how strong the pulses is, it as if the LED gets full voltage. The brightest a LED can go.
I never realized that this was a factor. I am trying to kick myself in the butt but I can’t reach.
Sorry guys.
I am reconstructing the unit off all the damage I did to the tracks now so will let you know what happens.
I will also try the new design. Who knows. Maybe both could be posted with pc boards on the web site.
Pieter
My humblest apologies to every one on the forum !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I found out by accident that with pin 4 on IC1 connected works.
The fact of the matter is that my computer is on the work bench. Having said this the magnetic pulses generated by the computer screen caused D1 to light. No matter in whatever position you turn R8 the led stayed lit. This was also the reason that the buzzer went beep on a per second basis. My computer hanged and I had to switch it off. Only when I did this I noticed that the led had gone dead. After restarting I moved away from the computer. The further away I moved the dimmer it got. So for about 2m + D1 goes out completely.
To give you an indication how strong the pulses is, it as if the LED gets full voltage. The brightest a LED can go.
I never realized that this was a factor. I am trying to kick myself in the butt but I can’t reach.
Sorry guys.
I am reconstructing the unit off all the damage I did to the tracks now so will let you know what happens.
I will also try the new design. Who knows. Maybe both could be posted with pc boards on the web site.
Pieter
audioguru2
- Apr 6, 2004
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Hi Pieter,
Sure, the pickup coil picks-up magnetic pulses from your monitor too. Thanks for letting us know. ;D
Sure, the pickup coil picks-up magnetic pulses from your monitor too. Thanks for letting us know. ;D
Hi Audioguru
A small problem.
I need to change some resistor values in the warning part of the circuit.(Old circuit) When I set R11 to 47K it moans on 1000 rpm. When I adjust R11 to 0 the highest revs I get is 1500 rpm. I need to gain at least another 2000 rpm. Because I cant go further than zero I assume that lowering some resistor values, would do the trick.
So I’m not sure which ones.
Any suggestions as to what resistors I could change.
Thanks
Pieter
A small problem.
I need to change some resistor values in the warning part of the circuit.(Old circuit) When I set R11 to 47K it moans on 1000 rpm. When I adjust R11 to 0 the highest revs I get is 1500 rpm. I need to gain at least another 2000 rpm. Because I cant go further than zero I assume that lowering some resistor values, would do the trick.
So I’m not sure which ones.
Any suggestions as to what resistors I could change.
Thanks
Pieter
audioguru2
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Hi Pieter,
In the original project, didn't you remove R10? It scales-up the RPM range a little.
I think R11 could be adjusted for higher RPM's if you reduce the value of R12 maybe to about 27k. Then the setting of R11 would be very sensitive near zero ohms so should also be reduced to about 20k.
Instead of changing all those resistors, try 47nF for C3. ;D
In the original project, didn't you remove R10? It scales-up the RPM range a little.
I think R11 could be adjusted for higher RPM's if you reduce the value of R12 maybe to about 27k. Then the setting of R11 would be very sensitive near zero ohms so should also be reduced to about 20k.
Instead of changing all those resistors, try 47nF for C3. ;D
Hi Audioguru
In the right up the author sugested the following.
Depending on the engine's cylinders number, R11 can be unable to set the device properly. In some cases you must use R11=200K and R12=100K or less.
I did follow his advice but with with little change. So I thought I could make changes somewhere else. With your advice I have more room for improvement.
The thing is that I don't want to tamper with components that might afect others. Thus causing more harm than good.
I will try your advise and let you know
Thanks
Pieter
In the right up the author sugested the following.
Depending on the engine's cylinders number, R11 can be unable to set the device properly. In some cases you must use R11=200K and R12=100K or less.
I did follow his advice but with with little change. So I thought I could make changes somewhere else. With your advice I have more room for improvement.
The thing is that I don't want to tamper with components that might afect others. Thus causing more harm than good.
I will try your advise and let you know
Thanks
Pieter
Hi Audioguru
What is wrong with this picture.
This is a Make before break single pin select switch. This configuration means the values of the 4 pots. Is there a different way of doing it or should I rather get a switch that select 2 pins simultaneously so that each pot could be selected individually?
Thanks
Pieter
View attachment 37124
What is wrong with this picture.
This is a Make before break single pin select switch. This configuration means the values of the 4 pots. Is there a different way of doing it or should I rather get a switch that select 2 pins simultaneously so that each pot could be selected individually?
Thanks
Pieter
View attachment 37124
audioguru2
- Apr 6, 2004
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Hi Audioguru
The black lines does represents the connections as you sugest. The switch also selects each pot individually.
What happens is that instead of each (SELECTED) pot adjusting between 0 and 100K, each selected pot adjust only between 55K and 85K. It doesn't go to zero and it doesn't go to near 100K.
How ever, If I only use ONE pot the adjustment goes between 0 and 100K
This is what I mean that it means (averages) the values
Pieter
The black lines does represents the connections as you sugest. The switch also selects each pot individually.
What happens is that instead of each (SELECTED) pot adjusting between 0 and 100K, each selected pot adjust only between 55K and 85K. It doesn't go to zero and it doesn't go to near 100K.
How ever, If I only use ONE pot the adjustment goes between 0 and 100K
This is what I mean that it means (averages) the values
Pieter
Last edited by a moderator:
audioguru2
- Apr 6, 2004
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Each 100k pot should adjust from zero ohms to 100k ohms. Maybe your reduced range is because R12 is in series with it and R10 is in parallel with both in series.
Audioguru
I meant to ask you. I have the project working in a way.
With this unit working on rpm it should warn on what ever revs are set.
In my car the unit is set for 2000rpm which represents approximately 60 kph.
When you pull away from stand still in first gear the revs reaches 2000rpm. Switching to second gear, before changing to third gear it reaches 2000 rpm.
So whilst changing gears the alarm sounds every time the revs reaches 2000rpm.
My question!!!!!!!!!!!!!!!
Is there a way that one can delay the alarm if the revs changes irregularly?
Or is there a way to make the unit respond ONLY when the revs has stabilized?
Any ideas to take the annoying beeps away whilst changing gears would be appreciated.
Thanks
Pieter
I meant to ask you. I have the project working in a way.
With this unit working on rpm it should warn on what ever revs are set.
In my car the unit is set for 2000rpm which represents approximately 60 kph.
When you pull away from stand still in first gear the revs reaches 2000rpm. Switching to second gear, before changing to third gear it reaches 2000 rpm.
So whilst changing gears the alarm sounds every time the revs reaches 2000rpm.
My question!!!!!!!!!!!!!!!
Is there a way that one can delay the alarm if the revs changes irregularly?
Or is there a way to make the unit respond ONLY when the revs has stabilized?
Any ideas to take the annoying beeps away whilst changing gears would be appreciated.
Thanks
Pieter
Last edited by a moderator:
audioguru2
- Apr 6, 2004
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Hi Pieter,
It ain't complicated and it ain't a speed-limit alert. It's an RPM alert! ;D ;D
If you want a speed sensor then drag a 5th wheel behind your vehicle.
Or you could hookup something to your ABS sensors.
You could slow the circuit's response time by increasing the value of the 1uF capacitor at pin 4 of the LM2917. Then it might be so slow it will drive you crazy! ;D ;D
It ain't complicated and it ain't a speed-limit alert. It's an RPM alert! ;D ;D
If you want a speed sensor then drag a 5th wheel behind your vehicle.
Or you could hookup something to your ABS sensors.
You could slow the circuit's response time by increasing the value of the 1uF capacitor at pin 4 of the LM2917. Then it might be so slow it will drive you crazy! ;D ;D
Hi Pieter,
It’s easy, you need a sensor for one of the drive shafts (if a front wheel drive) or the driveshaft if rear wheels drive! This way you are measuring the speed and not the RPM which is not related to the speed since you have more than one gear. 8)
It’s easy, you need a sensor for one of the drive shafts (if a front wheel drive) or the driveshaft if rear wheels drive! This way you are measuring the speed and not the RPM which is not related to the speed since you have more than one gear. 8)
Hi Ante
I was actualy playing around with audioguru and the 5th wheel. As you might have noticed from his posting that in my opinion I think he was sarcastic. So I humored him.
Anyway I was looking at magnetic sensors as well as reflective laser pick up's that works on a shaft. (Prop shaft or drive shafts).There is a variety of sensors (pick-up's) available. If one would go for the magnetic version then you would need something like a belt with magnets evenly spaced to go around the shaft. With the laser, you would need a piece of tape with black markings evenly spaced around the shaft.
http://www.shumatech.com/dro-350/add-ons.htm
http://www.jeffree.co.uk/Pages/speedmeasurement.html
I still think it is posible to change a component value to slow the response time in the original circuit to avoid the anoying beeps. . . . . . . . . . ;D
I would welcome any suggestions.
Pieter
I was actualy playing around with audioguru and the 5th wheel. As you might have noticed from his posting that in my opinion I think he was sarcastic. So I humored him.
Anyway I was looking at magnetic sensors as well as reflective laser pick up's that works on a shaft. (Prop shaft or drive shafts).There is a variety of sensors (pick-up's) available. If one would go for the magnetic version then you would need something like a belt with magnets evenly spaced to go around the shaft. With the laser, you would need a piece of tape with black markings evenly spaced around the shaft.
http://www.shumatech.com/dro-350/add-ons.htm
http://www.jeffree.co.uk/Pages/speedmeasurement.html
I still think it is posible to change a component value to slow the response time in the original circuit to avoid the anoying beeps. . . . . . . . . . ;D
I would welcome any suggestions.
Pieter
