What would it take to put out a simple working oscilloscope that would run over usb? An oscilloscope has always been something i’ve wanted, but couldn’t ever justify the price of, given my noob-hobbiest status.
My working knowledge of such things is very rudimentary, but from a high level, it seems like you’d just need to sample a few analog inputs very fast and graph them. All the rest is gravy.
this make article got me thinking about it… Oscilloscopes are something that makers (and sparkfunner’s) should build and open source. The thing i’m typing this on has more than enough power to display and record the data… all you need is a-d conversion… right?
In the end, i’m sure the software would probably be a complicated component… but it could potentially be built in a collaborative fashion similar to the arduino.
is there something like this out there already? (that’s cheap?)
Try googling ‘PIC scope’ or ‘PICscope’. The problem with all these a/d based scopes is the speed – the one you sent a link to only takes 100ksamples/second. This might be okay for things with very low clock frequencies, but when you get into higher speed digital systems the clock speeds are well into the megahertz.
You could always see if you could find a cheap scope off Ebay, or from a local electronics surplus place?
[Bitscope is an open source scope with reasonable prices if you want to buy one ready to go. At work we have several TDS 210 from Tektronix, they are good cheap digital scopes. For about $1800 brand new you can get a TDS 2014 which is a really decent 4 channel full color digital scope. Then again you can pick up a good analog scope for not very much, but they’re bulky and annoying to use…](http://www.bitscope.com)
That gadget would be useful for a few things like debugging communication protocalls, but it just seems too slow for anything else to me. Basic communication protocalls arent that hard to implement anyway so I wouldn’t be able to justify spending any money on it… all IMHO.
Parallax has a cheap low-end USB oscilloscope for about $130. The sample rate is very low and it only works for ±20V. It’s a very good introductary oscilloscope and it’s good enough for debugging audio amplifiers and communication protocols. It was good enough to let me see glitches in a RF link from inadequate power supply filtering and interferience from a PIC entering and exiting sleep mode between transferred bytes.
One of the biggest factors of cost in oscilloscopes is the bandwidth. The price increases sharply as the bandwidth increases. I was looking on the TekTronics website at several GHz oscilloscopes for viewing RF signals. The page made my fill out all kinds of customer information and when I finally got a quote it was several hundred thousand dollars.
mzoran:
One of the biggest factors of cost in oscilloscopes is the bandwidth. The price increases sharply as the bandwidth increases. I was looking on the TekTronics website at several GHz oscilloscopes for viewing RF signals. The page made my fill out all kinds of customer information and when I finally got a quote it was several hundred thousand dollars.
Greetings (No Name Supplied),
Did you mean Tektronix? (I used to work there…)
An oscilloscope is the wrong instrument to use for RF signals. A better choice would be a spectrum analyzer, although these are not cheap either.
For most applications in RF it’s the power level of the carrier or the modulation that’s of interest - not the ability to view the carrier cycle-by-cycle.
A simple detector diode and perhaps a low bandwidth amplifier together with a general purpose 'scope, or a general coverage radio reciever, will suffice.
My scope is a used Tektonix 464. I got it from a coworker for free. Ask around, if you do anything in the computer industry likely there are old electroincs people working with you who have old scopes in their basements. My coworker had three. He kept one, gave me one, and ebayed the other one for around $50.
Linear Technology has some eval kits you can buy that sample at 250 mHz and give you parallel data you can drop into a fifo, such as those from IDT. Or you can buy the Linear Tech adapter to the A-D kit that lets you get the data via USB.
Price the parts to see why speed is expensive.
Here’s an 8-bit Intersil part that samples at 160 msps that you can get from DigiKey for under $45.00 U.S. You’re going to want at least 2 channels.
We have a Tektronix TDS3014 that has four channels and when things get difficult all four are used. It is a 100 Mhz scope with 1.25 gsps.
Probably the biggest hurdle in making your own will be the PCB layout for those frequencies.