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Anenometer circuit troubleshooting (lm2917)

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Evo803

New Member
I am using a phototransistor ( nte 3037 ) to input (max 10hz) to the lm2917-14 and then have the output range from 0-5 vdc to supply to a lm3914 for display.

This is my first project and I can not figure out what I am doing wrong. I have been searching and reading but still cannot get it to work. I am hoping someone can help me figure this out.


Chris


ps I e-mailed National and they replied that the chips are old and I should use a MCU instead because it is newer and easier.
 

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  • windv1.pdf
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Shax

Member
What exactly isn't working?
Is the photo transistor shielded from all external light? If not, it'll be always on!
Have you checked that the lm3914 works? Use a resistive divider to inject some volts into its ass!!! :D
 

audioguru

Well-Known Member
Most Helpful Member
Aren't the posts on the other forum better?
I showed you the disconnected pins on your LM2917.

I even showed how you made the LEDs on the LM3914 extremely dim.
 

Evo803

New Member
What exactly isn't working?
Is the photo transistor shielded from all external light? If not, it'll be always on!
Have you checked that the lm3914 works? Use a resistive divider to inject some volts into its ass!!! :D

I cannot get the 2917 to output a linear variable voltage of 0-5vdc based on my input frequency of 0-10hz
 

audioguru

Well-Known Member
Most Helpful Member
1) Pin1 of the LM2917 and the emitter of the photo-transistor need a resistor to ground.
2) Pin11 of the LM2917 is its other input and needs to be set to a voltage for the LM2917 to trigger on (maybe near half the supply voltage).
3) The two resistors that program the LED current in the LM3914 must have much smaller values. The datasheet shows 1.2k instead of the 27k and the 180k also must have a much smaller value.
 

Evo803

New Member
1) Pin1 of the LM2917 and the emitter of the photo-transistor need a resistor to ground.
2) Pin11 of the LM2917 is its other input and needs to be set to a voltage for the LM2917 to trigger on (maybe near half the supply voltage).
3) The two resistors that program the LED current in the LM3914 must have much smaller values. The datasheet shows 1.2k instead of the 27k and the 180k also must have a much smaller value.

I did what you suggested and still no luck. I am still open for help I am not going to give up this should be very simple , but if anyone has any alternate ideas for a frquency to voltage converter I am open to input. This was suppoosed to be a birthday present , now its a christmas present .
 

audioguru

Well-Known Member
Most Helpful Member
You forgot to post your fixed schematic so we can see if your resistor values are useful.
 

Evo803

New Member
You forgot to post your fixed schematic so we can see if your resistor values are useful.

Here is what I have and still does not work.

I went back to hall sensor so I could increase hz input , no luck. I am going crazy , do think the ic could be bad. Any ideas for testing it ? Anyone have a schematic that they know works so I can test ?
 

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  • WINDV2.pdf
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Last edited:

MrDEB

Well-Known Member
I myself am designing an Anemometer circuit but going the PIC /LCD route.
similar sensor as a ps2 wheel mouse.
feel the magnets used for hall effect could slow down the Anemometer
I want accuracy for speed as well as working on a wind direction design.
An LM3914 isn't telling you much but sure looks nice.
oh the colors!
good luck
 

Evo803

New Member
I myself am designing an Anemometer circuit but going the PIC /LCD route.
similar sensor as a ps2 wheel mouse.
feel the magnets used for hall effect could slow down the Anemometer
I want accuracy for speed as well as working on a wind direction design.
An LM3914 isn't telling you much but sure looks nice.
oh the colors!
good luck

If I cant get this circuit working I will never be able to handle a mcu one:eek:

I was told of a couple of errors on my schematic here is the new one.
 

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  • WINDV3.pdf
    9.2 KB · Views: 143

audioguru

Well-Known Member
Most Helpful Member
Yes, without the 470 ohm resistor limiting the current in the zener diode in the IC then the IC blew up.
 
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