so do i need to add abit more between the inductive amp and the tone detection circuit?

also

as there anything i can do to further amplify the signal on the inductive amp without adding opamps ie chance component values or anything?? forgive me im on a steep learning curve here...

thanks

 

hi, me again

a question for hgmjr, looking at your design im building up a bill of materals, do the capacitors need to be polorised or non polorised, ive specified ceramic disc ones, should these be ok??

thanks

 

hi, me again

a question for hgmjr, looking at your design im building up a bill of materals, do the capacitors need to be polorised or non polorised, ive specified ceramic disc ones, should these be ok??

thanks

If you can get non-polarized 1uFd. that would be ideal. The timing caps need to be 10% tolerance.

Have you come up with a circuit to use to get the 5V logic levels from the audio output.

hgmjr

 

no not yet hgmjr, to be honest i hope i havent bit of more than i can chew. Although i got the inductive amplifier working so maybe with everyones help i can get the 'tone detection' part working too!

Also, i presume the circuit was designed on some software? does that software allow you to test it in a simulator? to be honest its been some years since i have used any software and things seem to of changed alot, i am hoping it will be 'easier' now to produce my own pcbs

 

Can I inquire what your project is about?

hgmjr

 

using an inductive amplifier to detect tones, similar to cable tracer except with a larger bandwidth,

editted to add

the operating enviroment is noisy, hence the led part of the project as headphones just wouldn't work

 

Have you come up with a circuit to use to get the 5V logic levels from the audio output.

i've been looking around for a circuit i been googling 'sine save to sqaure wave converter, inverter and many other combinations and cant find anything suitable

i don't think im upto this, can anyone help otherwise i will have to bin the whole idea, which is ashame as the inductor side works i just need to get this led working which is the harder part with all the filters etc...

editted to add

ive now got a bill of materials for all my components and will try and build 3 circuits less the 'coverter' part as i might be able to add this later

 

Hello,

Take a look at this page:
http://www.allaboutcircuits.com/vol_3/chpt_8/12.html
Look for the picture with the positive feedback resistor.
This will cancel some noise.

Greetings,
Bertus

 

would this circuit be suitable:

whats the varible resistor for? how would i calculate values of components and what ic would suitable for this application?

thanks

 

Hello,

The potmeter is to adjust the "switching level".
The Positive Feedback Resistor is to set the offset from the "switching level".
The Positive Feedback Resistor is most times 10 - 100 times the potmeter value.

Greetings,
Bertus

 

what ic would be suitable for this application?

thanks

 

Hello,

I have connected the diffrent schematics as I think it should work.

Greetings,
Bertus

 

sorry bertus.... a bone question....

whats that 7805 component with the two 10uf capacitors on it?

i identified the ic 311 as a comparator farnell ref
http://uk.farnell.com/stmicroelectronics/lm311n/volt-comparator-dip8-311/dp/9755942
will that be suitable?

so now the output of the circuit is square wave?

 

Hello,

The 7805 is a 5 volt stabelizer IC like a LM7805 or MC7805.
The preamp uses 9 Volts but the digital part runs at 5 Volts.

The 311 is indeed a LM311 comparator.
The inverter is one of the leftovers from hgmjr's inverters, to shape it real squarewave.

Greetings,
Bertus

 

would that leftover inverter be ic4 on hgmjr's schematic, in which case i specified http://uk.farnell.com/nxp/74hc00n/74hc-cmos-74hc00-dip14-5v/dp/380349
which farnell says ' Logic IC Function:Quadruple 2-Input NAND Gate' is this the wrong ic?
should i use this instead
http://uk.farnell.com/texas-instruments/cd74hc00e/ic-logic-74hc-inverter/dp/1607754

thanks

confused fred

 

Hello,

They are the same IC4 is a 74HC00, Quadruple 2-Input NAND Gate.
The other IC (IC2) in hgmjr's schematic is a 74hc14, a 6 inverter with schmitt trigger.
http://uk.farnell.com/texas-instruments/cd74hc14e/74hc-74hc14-dip14-6v/dp/2259783

Greetings,
Bertus

 

hi everyone

i have just made some calculations for a highpass and lowpass filters

low pass filter

freq = 3khz

r1 & r2 = 10k
cap1 = 7.5nf
cap2 = 3.5nf

highpass filter

fr1 =20k
r2=10k
cap 1,2 = 22nf

what do you guys think do these figues seem ok?

thanks
fred

 

Hello,

What filters are you talking about ?
Audioguru said he had then on an other site.
The calculations seem to be right.
Here are some calculators for the different filters.
http://www.educypedia.be/electronics/electroniccalculatorsfilter.htm

Greetings,
Bertus

 

i was talking about audioguru's suggestion, attached with led and high pass and low pass filters with my calculations. What do you make of this now I have put it all together..

 

Hello,

You could have the transistor between the LF351 and the filter for extra gain.

Greetings,
Bertus