Suggestions for a timer.

I'm trying to design a timer circuit. The current one that I have uses a 6.3 V 3300 uf Capacitor and a LM339 Quad comparitor, also a 5 segment LED Bar graph. I'm trying to make the timing adjustable with a Pot to the input of the capacitor. I'm want to have a time range between a minute to two and a half hours. I don't know a lot about ICs so if someone can suggest a good circuit. Please I could use the help. I haven't put the circuit up because it isn't finished yet.

Thank you

Duff

Here is a project on my site that may help you.

As well as the two circuit that I present, Many other variations are possible. It is a Very Useful IC.

**broken link removed**

Hope this helps.............Gary