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Flea-Scope: $18 Source Available USB Oscilloscope, Logic Analyzer and More [pdf]

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Re: Flea-Scope: $18 Source Available USB Oscilloscope, Logic Analyzer and More [pdf]

#21

Post by iceflinger »

serviceberry wrote: post #19

I think projects like that would have been a godsend 2-3 decades ago, when even a basic oscilloscope costed as much as a used car. Nowadays, very good oscilloscopes with 200 MHz bandwidth, good user interfaces, and responsive displays are selling for $300 - I'm talking Siglent, Rigol, UNI-T. So the merits of DIYing something much worse just aren't quite there. It's that one piece of equipment you use to troubleshoot…

I think there's something to be said for the form factor here though: I can see myself owning one of these just to take as part of a kit if I expect to need to do some troubleshooting away from my typical workspace.

Re: Flea-Scope: $18 Source Available USB Oscilloscope, Logic Analyzer and More [pdf]

#22

Post by gpm »

tonetegeatinst wrote: post #18
patrick451 wrote: post #9

Earlier quoted context omitted.

The only thing more frustrating than a rustacaen redefining "safety" to suit their purpose is a Stallman discipline redefining freedom to mean something totally weird. Something in the public domain is not free? Give me a break.

Can I get some context for the rustacian safety thing? I'm honestly interested if that's real.

"Memory safety" is a concept that predates rust, but was certainly popularized by it. It refers to statically eliminating a category of bugs - those related to misusing memory - and all sources of undefined behavior.

Rust code without unsafe blocks guarantees memory safety, and when you're writing unsafe blocks you're culturally expected to expose a safe-api that upholds rust's memory safety guarantees for users who don't themselves use unsafe blocks.

Rust programmers (rustaceans, a pun on crustacean because the language mascot is a crustacean) tend to extol the virtues of memory safety [1], and are sometimes lax with using the word "safety" to refer to "memory safety". There are obviously non-memory-safety safety considerations as well (e.g. the other 1/3rds of security vulnerabilities. Or all the non-software uses of the word like making buildings that don't fall down).

Personally I think it's usually pretty clear how the word is being used, and don't find it annoying. But then I'm a rust programmer.

[1] E.g. pointing out that roughly 2/3rds of security vulnerabilities are caused by the lack of it.

Re: Flea-Scope: $18 Source Available USB Oscilloscope, Logic Analyzer and More [pdf]

#23

Post by analog31 »

rmu09 wrote: post #17
analog31 wrote: post #6

Earlier quoted context omitted.

Also, looks like some parts are patented. https://patents.google.com/patent/US8117587B1

Strange patent. At first glance you could do something similar with an intel 8052AH BASIC (a 8051 type microcontroller with integrated basic interpreter) back in the 90ies.

Indeed, I built simple industrial controllers from 8052AH-BASIC chips. And lots of patents are strange. Sometimes the examination process results in a narrowing of the claims to the point where they don't really read on anything.

Re: Flea-Scope: $18 Source Available USB Oscilloscope, Logic Analyzer and More [pdf]

#24

Post by bobmcnamara »

burgerone wrote: post #15
dvh wrote: post #13

For comparison, this is what $2 USB scope (800ksps, 2 voltage ranges) look like: https://files.catbox.moe/0t0dq3.jpg

For yet another comparison, scoppy is a similar project: https://github.com/fhdm-dev/scoppy

I made something like this in college with a spare ADC, resistor divider, and an 8052.

Re: Flea-Scope: $18 Source Available USB Oscilloscope, Logic Analyzer and More [pdf]

#25

Post by nicolaslem »

iceflinger wrote: post #21
serviceberry wrote: post #19

I think projects like that would have been a godsend 2-3 decades ago, when even a basic oscilloscope costed as much as a used car. Nowadays, very good oscilloscopes with 200 MHz bandwidth, good user interfaces, and responsive displays are selling for $300 - I'm talking Siglent, Rigol, UNI-T. So the merits of DIYing something much worse just aren't quite there. It's that one piece of equipment you use to troubleshoot…

I think there's something to be said for the form factor here though: I can see myself owning one of these just to take as part of a kit if I expect to need to do some troubleshooting away from my typical workspace.

I have a cheap handheld oscilloscope (ZOYI ZT703S, ~$80) that I find very convenient to have around. It's the size of a multimeter, runs on a battery and works well enough that I don't feel too limited by it.

Re: Flea-Scope: $18 Source Available USB Oscilloscope, Logic Analyzer and More [pdf]

#26

Post by bramhaag »

patrick451 wrote: post #9
bramhaag wrote: post #5

Earlier quoted context omitted.

edit: parent was heavily edited, so this comment makes less sense now. Note that calling this FOSS is completely inaccurate. Some parts are all rights reserved, some are public domain and some are only available for non-commercial use. Public domain is not open source, and especially not free (as in freedom). Restricting commercial use is also not free. At best, this project is partially source-available.

The only thing more frustrating than a rustacaen redefining "safety" to suit their purpose is a Stallman discipline redefining freedom to mean something totally weird. Something in the public domain is not free? Give me a break.

> Something in the public domain is not free?

Copyright law is tricky. Under US law, "public domain" means "not copyrighted", the author waives all rights and the law allows them to release their works to the public domain. This you can consider free.

In other jurisdictions, say The Netherlands, the "Auteurswet" does not have a way for you to release your source code into the public domain, making any such statement void. Other countries such as Germany do not allow the author to waive all rights ("Urheberrecht"), etc etc.

Without knowing where the software was written, by whom the software was written and with whom it is shared, you cannot guarantee anything from "public domain" software.

Re: Flea-Scope: $18 Source Available USB Oscilloscope, Logic Analyzer and More [pdf]

#28

Post by bramhaag »

dkjaudyeqooe wrote: post #16
bramhaag wrote: post #5

Earlier quoted context omitted.

edit: parent was heavily edited, so this comment makes less sense now. Note that calling this FOSS is completely inaccurate. Some parts are all rights reserved, some are public domain and some are only available for non-commercial use. Public domain is not open source, and especially not free (as in freedom). Restricting commercial use is also not free. At best, this project is partially source-available.

> Public domain is not open source, and especially not free (as in freedom) How so? There are no restrictions on use or distribution. > Restricting commercial use is also not free. I agree, and I would include neutering any commercial uses, in which case GPL is non-free.

> How so? There are no restrictions on use or distribution.

It's not open source because it does not use an open source license (public domain is not a license). It's not free because this depends on your and the author's jurisdiction (if you both live in the US, then yes there are no restrictions on use or distribution)

> I would include neutering any commercial uses, in which case GPL is non-free.

In what way does GPL neuter commercial uses? GPLv3 simply states that you have to make your code available to your users (note: users, not everyone), not that you cannot sell your product.

Re: Flea-Scope: $18 Source Available USB Oscilloscope, Logic Analyzer and More [pdf]

#29

Post by fryd_w »

The flea-scope's hybrid FPGA/MCU architecture for USB streaming is clever - using FPGA pipelining to handle 100MS/s capture paired with an STM32 for protocol translation is sweet cost-wise. BUT, the 8-bit ADC resolution and lack of input protection networks (compared to Rigol's 1MΩ//20pF frontends with overvoltage clamping) make it risky in case of unattenuated signals.

The Python analysis toolkit using NumPy/SciPy for FFTs instead of baked-in DSP shows cool resource partitioning - could see Jupyter soon.

Re: Flea-Scope: $18 Source Available USB Oscilloscope, Logic Analyzer and More [pdf]

#30

Post by yjftsjthsd-h »

serviceberry wrote: post #19

I think projects like that would have been a godsend 2-3 decades ago, when even a basic oscilloscope costed as much as a used car. Nowadays, very good oscilloscopes with 200 MHz bandwidth, good user interfaces, and responsive displays are selling for $300 - I'm talking Siglent, Rigol, UNI-T. So the merits of DIYing something much worse just aren't quite there. It's that one piece of equipment you use to troubleshoot…

I think there's a difference in options at $200/$20/$2 (see elsewhere in this thread) just in lowering the bar to entry to the point of triviality. I'm not spending $300 without knowing exactly what I want it for, $20 is easy, $2 is an impulse buy.
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