DIY digital oscilloscope - Page 1
Forum section: electronics / projects

author: aiq25
author_rank: Regular Contributor
timestamp: April 06, 2015, 10:05:51 pm
content: Hi. I'm starting to come to a point in my electronics hobby where I need an oscilloscope. I don't have the money right now to buy a good one, so I was thinking about building myself a simple o-scope. I don't need many features because most of my work is in digital circuits, so I'm interested in knowing the noise levels in my signals and looking at digital signals (SPI, CAN, etc...). I stumbled upon the Freescale Freedom boards and they seem to go pretty high in clock/bus frequency. So I was thinking of using one of those boards to create a o-scope but I'm not sure how to really approach this. I know at super high frequencies it can get troublesome and I really don't want to make a custom PCB.Does anyone have any ideas or link that could help? I'm open to using other microcontrollers. Thank You.

author: Michaela Joy
author_rank: Contributor
timestamp: April 06, 2015, 11:09:46 pm
content: For the amount of work you'll have to do, I suggest you consider something like this.http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR3.TRC2.A0.H0.Xhantek6022be.TRS0&_nkw=hantek6022be&_sacat=0If you want to look at digital signals, you might consider a logic analyzer.http://www.ebay.com/itm/LWLA1034-125M-100M-34-channel-logic-analyzer-set-/111502236293?pt=LH_DefaultDomain_0&hash=item19f60d1a85Both of these work with a PC.

author: tggzzz
author_rank: Super Contributor
timestamp: April 06, 2015, 11:23:02 pm
content: There's an argument that, if you are principally interested in digital signals, you shoulduse an analogue scope to ensure signal integrity, i.e. that the inputs will interpret the signal correctly. Once that is the case, then...switch to the digital domain, and use a logic/protocol/network analyser or extra logic. There's no point in introducing questions along the line "is my receiver interpreting the signal the same way I am interpreting the scope trace?"In other words, don't bother to use an oscilloscope to debug digital signals.Ensuring signal integrity at a given bit/baud rate is much harder than debugging digits. For "ordinary" medium-speed signals you will need the analogue front end to have 100s of MHz bandwidth.

author: DanielS
author_rank: Frequent Contributor
timestamp: April 07, 2015, 03:10:10 am
content: The problem with attempting to duplicate a non-trivial commercial product at the one-off DIY scale is that you quickly end up spending more on components than the cost of simply buying the finished product off-the-shelf, only to achieve a fraction of the features with none of the reliability, accuracy and performance guarantees.You may want to consider saving until you can afford a DS1054Z - it could very well be cheaper than a DIY attempt and certainly far less frustrating.I would not recommend building a "basic scope" unless it was primarily out of curiosity or for a specific purpose. Building a scope without having a working scope to troubleshoot it with could get complicated.

author: aiq25
author_rank: Regular Contributor
timestamp: April 07, 2015, 03:21:55 am
content: What do you guys think about of the Siglent SDS1052DL? I might just end up getting an o-scope. Also what does the "50 MHz" on that o-scope mean?

author: bitwelder
author_rank: Super Contributor
timestamp: April 07, 2015, 05:26:05 am
content: Quote from: aiq25 on April 07, 2015, 03:21:55 amYou may want to have a look at EEVblog#13 (part 1 and 2)

author: stevech
author_rank: Contributor
timestamp: April 07, 2015, 05:50:13 am
content: I use/recommend a Hantek DSO2090. Search eBay.