OT: What should I build.

[cdngunner]

OK so I am spring cleaning and came across one of these DPM 700.

http://docs-europe.electrocomponents.com/webdocs/0750/0900766b8075001a.pdf

According to the paper work it can be set up to do a number of things. One of which is a frequency meter using a frequency to voltage converter.

I have a few multi meters but non have Hz. So I thought this might become a dedicated meter for all my Picaxe projects

I have no clue as to what range it would be but if you look at the last page from the PDF it gives you the circuit.

Is there any way it might measure Khz or even MHz?????

If its useless for that what else would you suggest I make from it?

 

[BeanieBots]

No reason it couldn't be used to display GHz.
Simply put a pre-scaler (divider) in front.
A PICAXE could then be used to alter the level of pre-scale.

 

[cdngunner]

No reason it couldn't be used to display GHz.
Simply put a pre-scaler (divider) in front.
A PICAXE could then be used to alter the level of pre-scale.

Have you forgoten that I am daft when it comes to electronics. At best I could coble together the indicated circuit. To think that I could understand, or modify said circuit would be like expecting me to walk on water. lmao.

 

[Jaguarjoe]

That's a nice meter that you have there. It is a DC voltmeter so whatever you chose to measure with it must be converted to DC volts first.
The frequency meter circuit shown in the spec sheet uses a 7555 IC to make that conversion. The frequencies that it will convert are dependent upon the RC network connected to the IC. Unfortunately, I could not find that same circuit anyplace else so I don't know the formula for R,C and frequency.
That 7555 looks like a variant of the ubiquitous 555 timer. Maybe there's a 555 tutorial that could help.
I did find another F to V converter:

http://www.datasheetcatalog.org/datasheet/nationalsemiconductor/DS007942.PDF

This one has a detailed explanation of how it works and how to hook it up. They're cheap too.