FScope Board #68
Replies: 3 comments 11 replies
-
|
Hi Jason, I assume you came across this: https://oscilloscope.fhdm.xyz/wiki/fscope-250k5-v2 As you can see from the photo the board is mainly SMD components so the only soldering required is some pin headers, the trimmer caps and the Pico (either via headers or directly to the board). The design is published here at OSHWLAB. To view the schematic tap/click one of the 'Open In Editor' buttons (which will open it in EasyEDA). If you're interested in purchasing some boards please email me at scoppy@fhdm.xyz. The price for 5 boards would be AUD$89 including shipping to Canada. Alternatively you could get the boards made yourself. It's just a matter of selecting 'One click order PCB/SMT' from the Fabrication menu in EasyEDA. This will take you to JLCPCB and then you follow the prompts. I can write some instructions if you're interested in going down this route. .... and I look forward to seeing your design 😄 Cheers, |
Beta Was this translation helpful? Give feedback.
-
|
Cool. I'll put in an order to get some boards manufactured. They should arrive here in about 3 weeks time and I'll make sure the store up and running well before then. And thanks for sharing your design - nice.
|
Beta Was this translation helpful? Give feedback.
-
|
The first round of single-sided board design has worked out well... it is interesting being able to swap out the OpAmps and seeing what they can do. I was trying to use up a bunch of LM324's on this project and was able to get decent enough 0-3V3 performance on the outputs, but then was reminded that the inputs aren't so forgiving of low voltage applications. That and the slew rate was just a bit poky... the TLC274 and MCP6024 both worked better. By the time I added the logic analyzer inputs (just resistor and Zener for protection) and shrunk the board down a bit I gave up on trying to do a single-sided routing job. My double sided boards should be hear to try out next week. I've decided to keep it down to one opamp, so am using two channels to buffer inputs one and two, one channel to amplify channel one (for 10x gain or so... my design specs are +/-33V and +/-3.3V operation, but of course that is highly tweakable with different resistor selections. I'm only running Channel 2 at the higher voltage input... although again, that range can be set as desired... maybe +/- 15V would make more sense on Channel 2. The fourth opamp channel is used for amplifying the Signal Generator output, so that it can drive a small speaker, or something, at 5V. The CD4052B allows me to switch the signal generator from pulse to sine... voltage modes 0 and 1 will change the gain on channel one, but give pulsed output, voltage modes 2 and 3 will give the same inputs, but sine output. At least that's my theory... I'll be testing some of that out next week. While comparing the board to the older DPScope design, I noticed that Wolfgang had used some neat measurement techniques to get around working with an older, slower, uC. The PIC on his board had a maximum sample rate of 20 ksps, but he re-measured repeating signals multiple times and was able to generate an effective 1 Msps on repeating signals. A neat trick! I think he also used a bit of averaging to knock the noise down a bit. Fusion 360 schematics and pcb still at https://a360.co/3zia7be Thanks for making such an interesting project... it has been fun working on this! (Fingers crossed that the two sided boards turn out okay!) Jason |
Beta Was this translation helpful? Give feedback.

Uh oh!
There was an error while loading. Please reload this page.
-
Thanks for everything you've built and shared with Scoppy. It's very cool.
I teach introductory electronics to future high school Technology Education ("shop") teachers in Vancouver, BC. In the past I have had them build the DPScope SE (http://dpscope.freevar.com/overview_se.html) as it is a great way to get a basic scope, but also to learn about some of the components that go into the scope. The author of that project has a great description of his front end, design choices, and an amazing assembly guide on his website.
I was in the midst of translating some of his front end design to work with Scoppy when I went on holidays... when I came back and checked for updates I noticed the fscope board mentioned in the wiki, but not information on how to acquire one or study the design in more detail.
I realize that a project like this can suck up a LOT of time, so my apologies if it is in the "more information coming soon" category. I'll carry on with my design as I'm aiming for a board with through-hole components and look forward to what you can share about the fscope board, when you've got time to share it.
Thanks,
Jason
P.S. After years of lurking on Github, the Scoppy project finally got me to sign up for an account and make a post... and I'll definitely be sharing my design once it is tested and working.
Beta Was this translation helpful? Give feedback.
All reactions