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How bad can a $2.97 ADC be?

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Re: How bad can a $2.97 ADC be?

#131

Post by q3k »

piyh wrote: post #122
q3k wrote: post #43

Earlier quoted context omitted.

> Dissolving in boiling sulphuric acid/nitric acid will make quick work of most epoxy packaging That's the better method of course (results wise), but it's not nearly as accessible, hence my recent evangelism of the virtues of 2000 grit sandpaper.

I appreciate the effort, but the bar is already very high when you recommend a SEM in the same breath.

The SEM was cheaper than an optical microscope or a fume hood though :).

(also I don't recommend a SEM in the first post, a cheapo USB 'microscope' will do, I just happen to have had SEM images on hand)

Re: How bad can a $2.97 ADC be?

#132

Post by jacquesm »

doubleg72 wrote: post #117
jacquesm wrote: post #77

Earlier quoted context omitted.

You may as well start off with one of these then: https://phillipscorp.com/india/phillipsgrinding/phillips-sur... All you need is a serial port and some G-codes.

Surface grinders generally don’t use CNC, they are a simple machine.

In the 1950's, yes. But these days they definitely are CNC based.

https://www.rooy.nl/en/areas-of-expertise/surface-grinding/

Re: How bad can a $2.97 ADC be?

#133

Post by [deleted] »

throwup238 wrote: post #7

> So what’s going on with the cheap parts? My best guess is that these are either quite good copies, or failed parts that somehow made their way into the hobbyist supply chain. The vast majority of counterfeit chips I've seen were from ghost shifts but IIRC TI fabs all their analog parts in house, I doubt they're ghost shift parts or failed QC. I think its probably a relabeled ADS1015.

[deleted]

Re: How bad can a $2.97 ADC be?

#134

Post by kragen »

SuperMouse wrote: post #121
kragen wrote: post #109

Earlier quoted context omitted.

That's out of stock, though. Here are my other shockingly inexpensive MCUs at LCSC that were in stock at the time: links from 02025-03-16: https://www.lcsc.com/product-detail/Microcontrollers-MCU-MPU... #LCSC #pricing for 16-pin #CH32V003 #microcontrollers #electronics #hardware: 14.21¢ in quantity 500. Not the cheapest, but it’s a RISC-V with IIRC an on-board op-amp, though the linked datasheet only covers the CPU r…

The Padauk and Nyquest are barely useable. They are highly specialized devices (often ROM-only). Cheapest "general purpose" microcontrollers that have enough features for good developer experience are Puya and WCH. If you are a seasoned STM32 developer you will get used to them within a day. Examples: https://download.py32.org/Datasheet/en/PY32F071_Datasheet_Re... https://arvidtek.com/wp-content/uploads/2025/06/CH32V…

While I mostly agree, I have some small quibbles which I think will present a more complete picture.

I've had a good developer experience with 74LS00-family SSI chips (like the quad-NAND-gate 74LS00 and the hex-inverter 74LS04), so your mileage may vary.

Just to clarify, the Padauk and Nyquest chips I linked above are one-time programmable (PROM), not mask ROM, except the PFS122 (3.53¢), which is reprogrammable Flash. (It's advisable to debug your code with a Flash chip or an ICE before you start consuming PROM chips, unless you really like to desolder.) Padauk doesn't seem to make mask-ROM chips at all, and I haven't seen any from Nyquest.

I'm not sure what you mean by "highly specialized". They're tiny, slow 8-bit microcontrollers, so you will certainly be disappointed if you go in hoping for STM32-like capabilities. But they're programmable, and their peripherals don't include things like LiDAR pulse timing circuits or AES encryption hardware or anything like that. It's just very general-purpose stuff like watchdog timers and PWM generators.

Re: How bad can a $2.97 ADC be?

#135

Post by kragen »

kragen wrote: post #107
gsmecher wrote: post #37

Earlier quoted context omitted.

Oh my - good find, and also, eek. Analogy: https://datasheet.lcsc.com/lcsc/2302211830_analogysemi-ADX11... TI: https://www.ti.com/lit/ds/symlink/ads1115.pdf Analogy's datasheet is directly cribbed from TI's (see TI Fig. 7-7 / Analogy Fig. 22½, pg. 18). This already passes my "run away screaming" threshold for trust, but a decapping would help me understand whether they've stolen the physical design (bad) or just clon…

"Stealing" the physical design is legal after 10 years in the US ( https://en.wikipedia.org/wiki/Integrated_circuit_layout_desi... ), or 20 years if there's a patent, and that's how we avoided having a single giant company own everything and halt innovation forever in the First and Second Industrial Revolutions. So I would say that stealing the physical design is good.

(I guess it was also important that at the time it was illegal for one company to own another, which was a significant obstacle to the rise of conglomerates like Standard Oil.)

Re: How bad can a $2.97 ADC be?

#136

Post by userbinator »

mschuster91 wrote: post #68
q3k wrote: post #51

Earlier quoted context omitted.

> or just cloned it (bad) What's wrong with cloning a chip functionality-wise? This is basically how the industry has operated since its infancy, and what gave us jelly bean logic parts and transistors, x86 and the PC revolution, ... (just talking about the cloning part here, not counterfeit markings or datasheet copyright infringement, or copying mask work)

If it's an open clone that can be reasonably distinguished from software side and from looking at the part and it doesn't violate IP laws other than software patents, no biggie. Every clone of any sufficiently complex Thing will have subtle quirks and edge cases compared to the original and as long as I can work around them for only that specific clone model, that's easy. But clones that have no way of determining if…

that can be reasonably distinguished from software side

That defeats the point of it being a clone. 100% the same is the goal.

Re: How bad can a $2.97 ADC be?

#137

Post by beachy »

camtarn wrote: post #130
beachy wrote: post #29

I'd like to know more about the world of ADCs. I've used the ADS1115 with success but only at very slow speeds. On the current project we started with an MCP3208 via SPI. It did the job but only has 8 channels and it's slow (100K samples per sec). To get something faster we switched to ADS7953. It has 16 channels and runs 10 times faster. It's somewhat more complex to code, and you can only get the highest sample rat…

Hah, damn. We live in different worlds - in mine, 100K samples/sec is blazingly fast! I'm currently working on a PLC program, replacing the PLC's basic cyclic input sampling (max 2K samples/sec) with a harder-to-use mechanism that lets you access the raw data off its 12-bit ADC at 10K samples/sec, which we consider unusually speedy.

Yeah, it's all a matter of perspective.

We have another project that measures levels in water tanks. A sample rate of 1 sample per minute is plenty.

Re: How bad can a $2.97 ADC be?

#138

Post by dazhbog »

"I picked up breakout boards from Amazon for $2.97 if you buy four, and I very much think these are made with the $0.60 parts from LCSC or similar."

There you are. Assumptions. Nothing to do with LCSC.

Re: How bad can a $2.97 ADC be?

#139

Post by ted_dunning »

clw8 wrote: post #127
RobKohr wrote: post #28

ADC = Analog to digital converter Takes an analog signal from something like light or sound and convert it into a digital signal. Acronyms introduced in an article should be spelled out at least once please.

For regular readers of this blog, that would be like defining USB for a general tech audience. Other articles by this author expect the reader to also know terms like I2C and SPI.

Most readers of this blog probably still can't define USB beyond "what you get when you stick this kind of cable into that kind of hole in your computer"
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