Hello,
I want to built a digital voltmeter and be capable to read the voltage from a program written in vb that will help in a project i have for my university. I want to use serial or parallel port . I have programming skills and if it would possible to provide me with some schematics or ideas of how to do it i would be very thankfull
thank you

 

hi,
Are you able to get a MCP3202 dual 12 bit, analog to digital convertor ic for the project.?

EDIT:
Added pdf of I/F

Attached Files

Parallel_IF2.pdf (29.0 KB, 43 views)

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
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I think i can i will go tommorow to the electonic store to buy it and test the circuit. One more question thought what range of voltage i can read with that circuit and with what accuracy.
thank you

 

hi,
The resolution of the MCP3202 is 12bits [4096].
The MCP can accept 0V thru +5V when powered by +5Volts.

The CA3240 dual OPA can be set to accept a range of input voltages, the input voltage can be attenuated with the pot on the NI input of the OPA or amplified by adjusting the OPA gain pot.

If you have a known range of voltages you need to measure, a switched fixed resistor attenuator and gain would be a good choice.

I have the Visual Basic 5 source code should you require it.

The 74LS07 o/c buffer ic is required.

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

 

that would awesome! and would save me a lot of time
thank you again
i will upload images when its done!

 

Let me know when you have obtained the MCP3202.

For information, I have also used the quad MCP3204 adc in the same way, to give 4 channels.

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

 

Sorry for not sending you back all this time but i had a lot of problems... Finaly i took all the ICs and completed the circuit yet i am facing problems with the vb code... I am using the inpout32.dll , Is it possible to send me your code to test it?? I also ordered the 8 input channel MCP3208 and i want to test it also!
Thanks anyway

 

hi,
Got your PM email, will email it Wed.

Attached zip for MCP3204 in VB5

Attached Files

DVM4zip1.zip (96.7 KB, 3 views)

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/