AFX School Project
Started by
betoe
, Jan 30 2004 05:43 AM
7 replies to this topic
#1
Posted 30 January 2004 - 05:43 AM
Hi guys, i want to make an AFX osciloscope!!! watch this link, it have some help for put a signal on a calculator, but i dont know how to determinate the frequency (my friend and me know how to make 8086/c programs, and how to put signal values in the calculator, and i think that we can graph them).
FX data logger
I have another idea: introduce the signal to a ADC (8 bits or more), then to a 8051CPU (it have serial port communication) for send the data to the calculater. Then all the rest is pure software. A teacher told me this for the frequency: obtain the TDF (discrete fourier) of the signal. What the F*** how to do that... Hope i can do this project.
FX data logger
I have another idea: introduce the signal to a ADC (8 bits or more), then to a 8051CPU (it have serial port communication) for send the data to the calculater. Then all the rest is pure software. A teacher told me this for the frequency: obtain the TDF (discrete fourier) of the signal. What the F*** how to do that... Hope i can do this project.
#2
Posted 30 January 2004 - 09:01 AM
Casio has already build such a thing, I don't remember the name, but you can find it on their site.
#3
Posted 30 January 2004 - 11:09 AM
and there is that data sampler that i showed you a while back, that would only need to be modified
#4
Posted 30 January 2004 - 09:13 PM
Oh yes i didnt remember that. I would like to be more like an osciloscope, that bring frequency etc... The bad thing, as i think, is that the higher frequency for that AFX osciloscope will be:
For send a byte we need 10 bits (8 of data, 2 of stop), and the max speed of the AFX serial port is 115,000bits/seg. I think that the max frequency that this oscilloscope will be around 6KHz , its too small.
For send a byte we need 10 bits (8 of data, 2 of stop), and the max speed of the AFX serial port is 115,000bits/seg. I think that the max frequency that this oscilloscope will be around 6KHz , its too small.
#5
Posted 31 January 2004 - 10:03 AM
you could always buffer the input on the hardware, then send it in bursts to the AFX, therefore making i t lag but having a higher frequency
#6
Posted 31 January 2004 - 06:18 PM
What is that? Do you mean tha EA-100 & EA-200?Casio has already build such a thing, I don't remember the name, but you can find it on their site.
Again, where is that? I'd love to see such things.and there is that data sampler that i showed you a while back, that would only need to be modified
betoe:
WOW, finally you get an interesting project.
It seems nice, and I looked at the page you linked, very interesting.
As for the frequency thing, I don't have a clue how you're going to get doing the DFT (or TDF if you're studying in French, they always turn sentences upside down ) using the AFX or the ASM language!!!
I might think you'd want to get the zero crossings for the signal, measure the number of clock cycles it takes for a period or half a period (every ASM command takes a certain number of clock cycles, you get that from the micro controller's data sheet), then by knowing the frequency of the crystal, you get to know approximately the frequenct you want.
But that souns like a dumb idea (I used it once in an opposite way to generate a signal with a certain frequency), there must be a smarter way like that DFT, I'll just look on the net for how these digital frequency measuring devices are made.
Please keep us updated and good luck.
#7
Posted 31 January 2004 - 07:10 PM
here is the link to the data logger: http://www.riccibitti.com/casio.htm
the only problem is the ADC chip costs ?20:00
the only problem is the ADC chip costs ?20:00
#8
Posted 31 January 2004 - 10:32 PM
For the zero crossings there is no problem. One doubt, what CPU is fastest, the NECV30 (of the AFX) or the 8051CPU at 12MHz? Damn i told this project to my teacher and he dont like this idea , he told me that i must do other project. Anyway i'm interested in it.
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