Turn your PC into a free oscilloscope
with ADC0820 connected to the printer parallel port
I was doing an ultrasound project when at one point I couldn't move forward without an oscilloscope.
I'm hobbyst in electronics, and I don't really need a real oscilloscope. I don't want to spend money on it and I don't have enough space in my electronics corner for it.
So, I took a look what is offering at the Net. I found a great (and free) solution: Zelscope. It's using the sound card and that's all you need. The problem with this solution is that you just can't get the sample rate more than 44kSamples/sec. That's enough for audio signals(<15kHz), but not for 40kHz ultrasound signals. You need around 10 samples per cycle (or more) of the signal you are measuring to get any decent waveform to actually view.
Here are some other PC oscilloscope projects and links:
Some useful stuff at epanorama
Bitscope - my favorite. But too good for my needs.
And there are also others (some are very expensive) "Turn your PC in an oscilloscope" products.
I wasn't quite happy with any of these solutions, so I started with my own design. Check the hardware page for schematics, and software for the program.
This table shows real max sample rates you can expect from this oscilloscope:
|Machine type||Sample rate (kSamples/sec)|
|Pentium MMX at 233 MHz||180|
|Pentium4 at 1.6 GHz||257|
|AthlonXP 1.7 GHz||267|