Modifying this oscillator to achieve lower frequencies?

[AFex54]

http://www.instructables.com/id/THE-SIMPLEST-FUNCTION-GENERATOR-BUILT-ON-A-BREADBO/

I was drawn to this oscillator because it uses an LM324 which i happened to have lying around and it also has 3 waveforms, including a sine which i needed.
however its frequency range is not ideal, it goes well above the range of human hearing to 5MHz which is useless to me and only as low as 500hz** when id prefer it more near 1- 10Hz .
how would i go about changing this?
i am very much a noob but i do know that this is possible with the LM324 because the MFOS Alien Screamer noise box uses it too and can go as low 10Hz
would appreciate the help !

** Im basing this fact on a persons comment from that instructable: ''hey could you tell me what is the range of frequency it works? Actually I don't know if I'm right, according to the equation it should be from 500Hz to aprox 5MHz.''

 

[(*steve*)]

That circuit has a large number of problems.

1. The square wave output is not buffered. Any loading here will affect the other waveforms.
2. The triangular wave output is not buffered and any loading will affect the "sine" wave output.
3. The sine wave output will not be very clean.
4. The triangular wave amplitude will vary with frequency.
5. The sine wave "quality" will vary with frequency.

If you can live with this, the simple way to reduce the frequency of operation is to increase the value of C1. 1uF rather than 0.01uF will give you a frequency 100 times lower.

Note that you will probably need to adjust C2 and C3 to get useable triangular and sine outputs.

 

[davenn]

and to get a specific freq use the formula they gave
it should give you a close ballpark figure ......

The frequency of this oscillation is given by F= 1/(2RC).

Therefore, by varying the trim pot R the frequency can be changed.

Dave

 

[AFex54]

That circuit has a large number of problems.

1. The square wave output is not buffered. Any loading here will affect the other waveforms.
2. The triangular wave output is not buffered and any loading will affect the "sine" wave output.
3. The sine wave output will not be very clean.
4. The triangular wave amplitude will vary with frequency.
5. The sine wave "quality" will vary with frequency.

If you can live with this, the simple way to reduce the frequency of operation is to increase the value of C1. 1uF rather than 0.01uF will give you a frequency 100 times lower.

Note that you will probably need to adjust C2 and C3 to get useable triangular and sine outputs.

you know what i think ill stick with this schematic , im curious as to what the next step down from Lo-Fi sounds like...'No-Fi' if you like.
im wondering is there any small modification that can be made to the circuit to clean up the sound a bit ?
perhaps that is much easier said than done

 

[(*steve*)]

perhaps that is much easier said than done

Short of using a chip that is designed to produce these waveforms, there's not much "simple" you can do to improve it.