On 1/20/2023 8:14 PM, Paul Rubin wrote:> Theo <theom+news@chiark.greenend.org.uk> writes: >> What is the use case for a programmable RS232-to-RS232 product? If >> you can think of a use case, maybe you can find somebody who makes >> such a thing. > > The search is not for an RS232-to-RS232 product per se, but for a small > computer with two RS232 ports. In the Z80 era, those used to be > plentiful. Of course they were considered full fledged personal > computers, in large expensive boxes, given the technology of time.A `7180 with some level-shifters would be a 3-chip solution "from the past". But, you'd "program" it as a PROM, not some ASL.> The lament is that there doesn't seem to be anything like that being > made today with modern technology. Just a small box with a programmable > microprocessor inside, and two RS232 ports. All the available products > add a massive amount of additional complexity. It does seem like an > opportunity. > > Imagining making something like that for myself makes me feel dismayed. > Besides the MCU board and enclosure, you also need a bunch of mounting > screws, standoffs, connectors, an enclosure made of sheet metal, tools > to drill holes for the standoffs and make D-shaped cutouts for the DB9 > connectors, burn-in testing for everything, yada yada yada. All that > stuff would have to be ordered from someplace, maybe multiple places.More importantly, you'd have to CONSTRAIN yourself to ONLY putting those two serial ports in the design. (Hmmm, should they support modem control signals? hardware handshaking? flow control? what if I want to connect it to something -- in the FUTURE -- that has one of those needs, beyond Rd/Td?) Should it be programmable as a masked part? Or, some sort of interpreted language? What range of bit rates should it support? 134.5? 115.2K? I mean, if you're going to all the trouble to design/build something, wouldn't you want to make it as "universal" as possible? I.e., like a VENDOR supplying a product to the largest possible market for a given price point?> Whenever I try to make anything physical, I invariably discover partway > through that I need some 10 cent part that I didn't think of earlier, so > I have to order that and wait N days for its arrival, then repeat this > process several times. This is why custom made anything costs so much.No, folks who make custom devices for a living already have those items on hand. They likely use a particular set of components, hardware, enclosures, etc. Because they don't want to have to incur *extra* costs just to put it in a ROUND box (instead of square).> It's not like programming where if I need some chunk of software, I can > download it and have it a minute later. > > It doesn't seem like THAT outlandish a wish to hope that box described > instead exists as an off the shelf product from somewhere. It is weird > that it is so hard to find.Why do you consider it weird? What use do folks have of EIA232 devices, nowadays? Are they even commonplace on PCs? Or, have they gone the way of the floppy disk, parallel port, PCMCIA slots, ISA bus, etc.? How much longer before optical discs will be obsolete (instead of just obsolescent)? Other than the "fallback interface" on my UPSs (in case the ethernet i/f is not functioning), I can't think of a use that merits my having a "serial cable" on hand. (I think I have an old ICE that used a serial port) Even my older printers only use SHORT parallel cables to connect to 1/2/3-port print servers (do I have ANY parallel ports anymore?)! [The Market weeds out items that it doesn't consider to be of practical use] ISTM that the entry-level product would be something with an ethernet (or BT) port and ____________. Like a 1/2/3/etc. port terminal server to bridge that obsolescent technology (EIA232) to more modern comms. "You mean you have to connect that device directly to the machine that USES it???" What can you do with JUST a pair of serial ports? (because of the requirement for it to be "in a box" and, thus, a *complete* product, with just those I/Os). And, if the number of use cases is small, you're likely going to pay a lot for that "special" ability. The last commercial product I designed with serial ports was almost 35 years ago. And, it's goal was to *monitor* serial data streams and provide remote notification and access to those ports (internal, chip-level 212A modem) when certain strings were detected. Nowadays, EVERYTHING has a network port and secure comms.
Boxed MCU with RS-232 Port
Started by ●January 17, 2023
Reply by ●January 20, 20232023-01-20
Reply by ●January 21, 20232023-01-21
Paul Rubin <no.email@nospam.invalid> wrote:> Theo <theom+news@chiark.greenend.org.uk> writes: > > What is the use case for a programmable RS232-to-RS232 product? If > > you can think of a use case, maybe you can find somebody who makes > > such a thing. > > The search is not for an RS232-to-RS232 product per se, but for a small > computer with two RS232 ports. In the Z80 era, those used to be > plentiful. Of course they were considered full fledged personal > computers, in large expensive boxes, given the technology of time. > > The lament is that there doesn't seem to be anything like that being > made today with modern technology. Just a small box with a programmable > microprocessor inside, and two RS232 ports. All the available products > add a massive amount of additional complexity. It does seem like an > opportunity.A 'small computer' these days is a PC or a Raspberry Pi. Something smaller than that isn't a 'computer', it's an 'embedded microcontroller' - and those are usually expressly designed not to be programmable. Which means we're left with repurposing something else where they happened to leave a JTAG/etc port exposed. A PC or Pi would be the wrong tool for the job IMO - one day you're going to turn the power on and find the storage is corrupted or failed and it won't boot. The suggestion of a PLC is a good one - that is a use case for a microcontroller-level programmable device, if you can put up with the size. The cheap Chinese PLCs might do the job (but Rick has vetoed that route).> Imagining making something like that for myself makes me feel dismayed. > Besides the MCU board and enclosure, you also need a bunch of mounting > screws, standoffs, connectors, an enclosure made of sheet metal, tools > to drill holes for the standoffs and make D-shaped cutouts for the DB9 > connectors, burn-in testing for everything, yada yada yada. All that > stuff would have to be ordered from someplace, maybe multiple places.I agree, it's a PITA. Particularly if your organisation is not set up for hardware manufacturing: if you need 100 units of the thing you aren't just going to solder them up and screw them together yourself, but contracting that volume out is annoying. Personally I would design for the enclosure. With the right enclosure, like the one I linked to, it would be PCB assembly - which you could more easily contract out - followed by clipping the enclosure around it. There would be no need for standoffs, screws, drilling, anything. But still clipping 100 enclosures over boards and packaging them up might not be something your org is set up to handle - eg if you're a strictly office setup and not designed for packaging and shipping.> It doesn't seem like THAT outlandish a wish to hope that box described > instead exists as an off the shelf product from somewhere. It is weird > that it is so hard to find.I think it's just that RS232 (at least in the DB9 form, UARTs are still everywhere) is increasingly legacy these days, so it's getting harder to find DB9s on things that aren't intended to convert away from RS232. The SCADA field is the only one I can think where microcontroller RS232 might still be popular. Theo
Reply by ●January 21, 20232023-01-21
On 1/20/2023 8:41 PM, Don Y wrote:> ISTM that the entry-level product would be something with an ethernet > (or BT) port and ____________. Like a 1/2/3/etc. port terminal server > to bridge that obsolescent technology (EIA232) to more modern comms. > "You mean you have to connect that device directly to the machine > that USES it???"I've one of these in my toy chest: <https://www.zdnet.com/article/shrunken-linux-enter-the-cerfcube/> Of course, $400 and 20 years ago is likely a non-starter! (and, as one of the six faces is explicitly omitted, I wonder if it qualifies as "boxed"?)
Reply by ●January 21, 20232023-01-21
Rick C <gnuarm.deletethisbit@gmail.com> wrote:> On Friday, January 20, 2023 at 8:58:49 PM UTC-5, anti...@math.uni.wroc.pl wrote: > > Rick C <gnuarm.del...@gmail.com> wrote: > > > On Friday, January 20, 2023 at 4:02:27 PM UTC-5, Dimiter wrote: > > > > On 1/20/2023 22:37, Rick C wrote: > > > > > On Friday, January 20, 2023 at 1:17:59 PM UTC-5, Herbert Kleebauer wrote: > > > > >> On 19.01.2023 19:06, Rick C wrote:<snip>> > > My experience with Alibaba is not the same as yours. With Ebay, I can dispute a sale and get a refund. Alibaba spent literally months demanding more and more things from me, many which made no sense because of the language barrier. In the end, they said I failed to prove the vendor was lying when he said he shipped the item listed. Photos were not good enough. They wanted a video for some reason. Alibaba simply does not support their customers, so I don't use them. Ebay is worth while, but some things sold are perpetually fake, or crap and you have to buy them to find out, then make the "return", which the vendor is required to pay for, so they often say keep it. > > > > > > I even bought crap wire on Ebay from a vendor relatively local. The actual wire gauge was about three numbers below the claimed AWG. Bought 20 gauge and got 23 gauge. Bought 18 gauge and got 21 gauge, etc. I was getting the refund, so I thought I'd try seeing how far this went. 16 gauge was actually 19 gauge and 12 gauge, was actually 15 gauge. The vendor could not say they didn't know, the wire insulation has *their* name on it! So it's a custom marked product. How could they not know they are selling mislabeled wire? > > > > > > Yeah, they all sell crap. I just find it possible to get a refund from Ebay. Alibaba, not so much. > > > > > IIUC Alibaba is intended for larger transactions and has different<snip>> No, they send something, just not anything of value. Aliexpress can't seem to understand the ICs which don't work, are counterfeit and you don't have to test every one on the reel to know they are all crap. The real issue was the language barrier. They don't speak English, rather use automated translators in both directions, so don't understand half of what you are saying. They also don't understand what an IC is and think counterfeit is only for handbags.My impression was that verndors understood resonably well what I wrote and answered sensibly. The things were probably too small to really involve a person from Aliexpress, communication from Aliexpress looked like canned text. So really no big problem with Engish, but potentially could be different if matters got more complicated (more value at stake and vendor contradicting my claims). BTW: Aliexpress want very much to translate offers into my native Polish. Compared to English text that they have translations into Polish are really funny/misleading.> > Most Aliexpress seller have resonably high volumes. They sell > > what customers want to buy. It can not be completely non functional, > > there are not enough fools to support this. > > LOL! If they buy counterfeit ICs at $0.05 each, they don't need to sell many at $5.00 to make profit.In general, probably 1 in 100 customers makes comments dealing with actual performance of given product. So after 100 sales, if thing is non-functional you can expect bad opinion and after that more folks looking at what they get and cascade of more bad opinions. Actually if thing is completely non-functional I would expect complaints much earlier. So maybe bad guy can collect few hundreds or maybe some thousends dollars. If one could do such thing without a cost, then surely, there would be a lot of folks doing this. But there is probably some cost setting Aliexpress seller account and if enetrprise is pure fraud, then Aliexpress is likely to take some action (say via court or police). My impression is that complete, pure fraud is not big problem. Rather, problematic are goods that appear to work but are substandard or have hidden defects.> > The problem is > > that most customers are unable or unwillig to fully examine > > what they bought. So you get rechargable batteries with > > completely bogus stated capacity or USB chargers with inflated > > charging current. I bought a lot of things on Aliexpress > > but I am trying to keep realistic expectations. I bought > > few USB chargers knowing that stated current (2.1 A) is > > much bigger than real one (0.85 A), but they were good enough > > for my purpose. I bought resistors and small power transistors. > > My reasoning was that making something that looks like resistor > > or transistor in small/medium volume is probably more expensive > > than real resistor/transistor in high volume. And hopefully > > there are not enough fools to fund high volume manufacturing > > of fake transistors. > > I don't think you understand. There are any number of things that look like the thing they are selling you, which will pass a visual inspection if you close one eye and have no idea what you are looking for. But they are fake. Even a $0.10 transistor has a lot of markup if they only pay $0.001 each for a reject. It might work well enough to light the LED on a transistor tester.I was writing about basic transitors like 2N3904, BC237 and similar. AFAICS $0.10 for such transistor is well above market price. Few years ago 2N3904 from big American distributor was $0.0234 per piece when you wanted 500. About 10 years ago reputable local distributor had basic types for equivelent of $0.015 per piece in quantities of 100. And BF493 was half of that. This distributor had a warehouse and same day (if order was early enough in the day) or next day shipping. Chinese seller had batches of 100, with prices of order $1 per batch, that is $0.01 per transitor. I was a bit curious so I looked at availability numbers. Apparently he started from 10000 and counter went relatively fast down. And then restarted from 10000. So he was selling milions of transitors (10000 times 100 is milion). I also looked at Farnell. For similar type they had something like 35000 and counters were slowly changing. So Chinese guy had _much_ larger volume than Farnell and almost surely much lower operating cost. At prices between $0.10 and $0.20 per piece I got few TO-220 powers MOSFETS. They were out of specs and probably rejects: both Rds_on and junction capacitance was larger than it should be, so this was not smaller MOSFET relabeled as bigger one. I consider them good enough for undemanding uses in experimental circuits. Certainly I would not allow them to get anywhere near production (too much risk that they would end up in critical circuits).> > Well, I got resistors and resonably > > performing transistors. I can not say if there are some hidden > > troubles but to the moment I am satisfied with what I bought. > > Sure, if you only need crap components, then you are good to go!If I had extreme requirements, then I would not use 2N3904 or BC237. But they are good enough for most uses.> > In the past I bought few STM chips from Chinese sellers. > > AFAIK those chips were widely used in China, the unit price was > > much lower than unit price from western distributors, but > > significantly higher that supposed volume price. So it > > looked resonable that Chinese seller could sell them at lower > > margin and still make a profit. And up to now I had no > > problem with those chips. > > > > OTOH if there is advanced/rare western part it would be strange > > if Chinese seller had some magic cheap source of the part, so > > I am very suspicious of such offers. Power mosfets were > > borderline case. Around 2019 I bought packs of 10 from several > > sellers. Essentially all were out of specs (too large Rds_on). If > > there were moderate discrepancy I made comments stating real paramenter, > > in few cases of really large discrepancy I requested partial > > refund (and got it possibly after a dispute). To say the truth, > > refunds that I got were probably not worth my time, I did this > > mostly from feeling of moral duty, to make sure sellers know > > that there is problem and to discourage them from selling such > > bad parts. > > > > When buying on Aliexpress it is useful to read buyers comments. > > Especially Russians tend to measure/test bought parts, so you > > can have resonable idea what you are buying. > > I've never found any selling sites with good reviews. Many are made up from whole cloth. I recall when Ebay had some sort of rating system in both directions. There were vendors who would set up buyer accounts and buy things at a penny. Good reviews in both directions and credibility would increase.There may be something like that at Aliexpress. But I meant actual text of comments. It would take some effort to make up text that is belivable and it is not clear what seller would gain. Aliexpress allow you to view opinions corresponding to given rating, so you can look up why people give bad rating (while good ratings frequently came with no text, bad ones usually give some justification).> Eventually Ebay put an end to it, partly by all but eliminating reviews of buyers. Now, I find very few sellers with fewer than thousands of ratings. If they have few ratings, or are below 99% positive, I avoid them if I have choice. One thing I've learned is to completely avoid flash drives on any of these sites. 90% of the time, they will fail a good memory test. Seems they use a flash drive 8 or 16 times smaller and flip the bits on the size reporting. They can sell a bunch of these before they are booted off the service.I never looked at flash drives online. I bought SD cards and at some time there was flood of fake cards that reported much higher capacity than they had. But then came programs that tested real capacity and it seems that problem essentialy vanished. At least for moderate capacities. -- Waldek Hebisch
Reply by ●January 22, 20232023-01-22
On Saturday, January 21, 2023 at 3:02:34 PM UTC-5, anti...@math.uni.wroc.pl wrote:> Rick C <gnuarm.del...@gmail.com> wrote: > > On Friday, January 20, 2023 at 8:58:49 PM UTC-5, anti...@math.uni.wroc.pl wrote: > > > Rick C <gnuarm.del...@gmail.com> wrote: > > > > On Friday, January 20, 2023 at 4:02:27 PM UTC-5, Dimiter wrote: > > > > > On 1/20/2023 22:37, Rick C wrote: > > > > > > On Friday, January 20, 2023 at 1:17:59 PM UTC-5, Herbert Kleebauer wrote: > > > > > >> On 19.01.2023 19:06, Rick C wrote: > <snip> > > > > My experience with Alibaba is not the same as yours. With Ebay, I can dispute a sale and get a refund. Alibaba spent literally months demanding more and more things from me, many which made no sense because of the language barrier. In the end, they said I failed to prove the vendor was lying when he said he shipped the item listed. Photos were not good enough. They wanted a video for some reason. Alibaba simply does not support their customers, so I don't use them. Ebay is worth while, but some things sold are perpetually fake, or crap and you have to buy them to find out, then make the "return", which the vendor is required to pay for, so they often say keep it. > > > > > > > > I even bought crap wire on Ebay from a vendor relatively local. The actual wire gauge was about three numbers below the claimed AWG. Bought 20 gauge and got 23 gauge. Bought 18 gauge and got 21 gauge, etc. I was getting the refund, so I thought I'd try seeing how far this went. 16 gauge was actually 19 gauge and 12 gauge, was actually 15 gauge. The vendor could not say they didn't know, the wire insulation has *their* name on it! So it's a custom marked product. How could they not know they are selling mislabeled wire? > > > > > > > > Yeah, they all sell crap. I just find it possible to get a refund from Ebay. Alibaba, not so much. > > > > > > > IIUC Alibaba is intended for larger transactions and has different > <snip> > > No, they send something, just not anything of value. Aliexpress can't seem to understand the ICs which don't work, are counterfeit and you don't have to test every one on the reel to know they are all crap. The real issue was the language barrier. They don't speak English, rather use automated translators in both directions, so don't understand half of what you are saying. They also don't understand what an IC is and think counterfeit is only for handbags. > My impression was that verndors understood resonably well what I > wrote and answered sensibly.I didn't say anything about the vendors not understanding. I'm talking about the dispute process. It is very heavily weighted in favor of the seller and on top of that, they have no language barrier. I had to read their Chinese, which they suddenly started using for the dispute and Alibaba use the translator to communicate with me. Much of the problem I had, was because they were asking me for very silly things, some of which was a language issue, no doubt, but also the fact that they are set up for selling funny clocks, t-shirts and handbags, not technically oriented items.> The things were probably too small to > really involve a person from Aliexpress, communication from > Aliexpress looked like canned text. So really no big problem with > Engish, but potentially could be different if matters got more > complicated (more value at stake and vendor contradicting my claims). > > BTW: Aliexpress want very much to translate offers into my native > Polish. Compared to English text that they have translations into > Polish are really funny/misleading.Oh, yes! The want very much to do what it takes the close the deal, they just don't care if you get ripped off.> > > Most Aliexpress seller have resonably high volumes. They sell > > > what customers want to buy. It can not be completely non functional, > > > there are not enough fools to support this. > > > > LOL! If they buy counterfeit ICs at $0.05 each, they don't need to sell many at $5.00 to make profit. > In general, probably 1 in 100 customers makes comments dealing with > actual performance of given product. So after 100 sales, if thing is > non-functional you can expect bad opinion and after that more folks > looking at what they get and cascade of more bad opinions.Alibaba doesn't work that way.> Actually > if thing is completely non-functional I would expect complaints > much earlier. So maybe bad guy can collect few hundreds or maybe > some thousends dollars. If one could do such thing without a cost, > then surely, there would be a lot of folks doing this. But there > is probably some cost setting Aliexpress seller account and if > enetrprise is pure fraud, then Aliexpress is likely to take some > action (say via court or police).Alibaba has virtually no effective rating system. What is there, is easily scammed by generating fake reviews and starting over with a new company name when you get bad reviews. Like Ebay in the early days. Ebay took the matter seriously, and stopping the vendors from being able to blacklist customers because the blue the whistle. I remember sellers threatening me to give good, or no reviews.> My impression is that complete, pure fraud is not big problem. > Rather, problematic are goods that appear to work but are substandard > or have hidden defects.Your impression is very wrong. "Hidden defects" such as being totally counterfeit, meaning likely some reject part in the same package, that's not even the same part number.> > > The problem is > > > that most customers are unable or unwillig to fully examine > > > what they bought. So you get rechargable batteries with > > > completely bogus stated capacity or USB chargers with inflated > > > charging current. I bought a lot of things on Aliexpress > > > but I am trying to keep realistic expectations. I bought > > > few USB chargers knowing that stated current (2.1 A) is > > > much bigger than real one (0.85 A), but they were good enough > > > for my purpose. I bought resistors and small power transistors. > > > My reasoning was that making something that looks like resistor > > > or transistor in small/medium volume is probably more expensive > > > than real resistor/transistor in high volume. And hopefully > > > there are not enough fools to fund high volume manufacturing > > > of fake transistors. > > > > I don't think you understand. There are any number of things that look like the thing they are selling you, which will pass a visual inspection if you close one eye and have no idea what you are looking for. But they are fake. Even a $0.10 transistor has a lot of markup if they only pay $0.001 each for a reject. It might work well enough to light the LED on a transistor tester. > I was writing about basic transitors like 2N3904, BC237 and similar. > AFAICS $0.10 for such transistor is well above market price.Dear god! It was just a number to illustrate the idea. Pick you own numbers.> Few > years ago 2N3904 from big American distributor was $0.0234 per piece when > you wanted 500. About 10 years ago reputable local distributor had > basic types for equivelent of $0.015 per piece in quantities of 100. > And BF493 was half of that. This distributor had a warehouse and > same day (if order was early enough in the day) or next day shipping. > > Chinese seller had batches of 100, with prices of order $1 per batch, > that is $0.01 per transitor. I was a bit curious so I looked at > availability numbers. Apparently he started from 10000 and counter > went relatively fast down. And then restarted from 10000. So > he was selling milions of transitors (10000 times 100 is milion). > I also looked at Farnell. For similar type they had something like > 35000 and counters were slowly changing. So Chinese guy had _much_ > larger volume than Farnell and almost surely much lower operating cost. > > At prices between $0.10 and $0.20 per piece I got few TO-220 > powers MOSFETS. They were out of specs and probably rejects: > both Rds_on and junction capacitance was larger than it should > be, so this was not smaller MOSFET relabeled as bigger one. > I consider them good enough for undemanding uses in experimental > circuits. Certainly I would not allow them to get anywhere > near production (too much risk that they would end up in > critical circuits).Ok, buy your transistors at Alibaba. Just don't buy anything that requires some real money.> > > Well, I got resistors and resonably > > > performing transistors. I can not say if there are some hidden > > > troubles but to the moment I am satisfied with what I bought. > > > > Sure, if you only need crap components, then you are good to go! > If I had extreme requirements, then I would not use 2N3904 or > BC237. But they are good enough for most uses.Ok, so you actually want 2Nxxxx and don't care what you really get. Fine.> > > In the past I bought few STM chips from Chinese sellers. > > > AFAIK those chips were widely used in China, the unit price was > > > much lower than unit price from western distributors, but > > > significantly higher that supposed volume price. So it > > > looked resonable that Chinese seller could sell them at lower > > > margin and still make a profit. And up to now I had no > > > problem with those chips. > > > > > > OTOH if there is advanced/rare western part it would be strange > > > if Chinese seller had some magic cheap source of the part, so > > > I am very suspicious of such offers. Power mosfets were > > > borderline case. Around 2019 I bought packs of 10 from several > > > sellers. Essentially all were out of specs (too large Rds_on). If > > > there were moderate discrepancy I made comments stating real paramenter, > > > in few cases of really large discrepancy I requested partial > > > refund (and got it possibly after a dispute). To say the truth, > > > refunds that I got were probably not worth my time, I did this > > > mostly from feeling of moral duty, to make sure sellers know > > > that there is problem and to discourage them from selling such > > > bad parts. > > > > > > When buying on Aliexpress it is useful to read buyers comments. > > > Especially Russians tend to measure/test bought parts, so you > > > can have resonable idea what you are buying. > > > > I've never found any selling sites with good reviews. Many are made up from whole cloth. I recall when Ebay had some sort of rating system in both directions. There were vendors who would set up buyer accounts and buy things at a penny. Good reviews in both directions and credibility would increase. > There may be something like that at Aliexpress. But I meant actual > text of comments. It would take some effort to make up text that > is belivable and it is not clear what seller would gain.LOL!!! No, that's the point. It so EASY to come up with fake reviews. Just lift reviews from some other vendor. Copy-paste. That's the easy part. The hard part is setting up the new account after your old one has been ratted out. So 10 minutes, rather than just 5 minutes.> Aliexpress > allow you to view opinions corresponding to given rating, so you > can look up why people give bad rating (while good ratings frequently > came with no text, bad ones usually give some justification).Not talking about Aliexpress. Talking about Alibaba. Aliexpress is not much different. They just work with smaller numbers. I think the last time I used Aliexpress, I ordered two of the same FPGA boards, one with a display and one without. They shipped one FPGA board and one display. The vendor would not acknowledge my messages. Aliexpress did nothing. I had to dispute it on the credit card.> > Eventually Ebay put an end to it, partly by all but eliminating reviews of buyers. Now, I find very few sellers with fewer than thousands of ratings. If they have few ratings, or are below 99% positive, I avoid them if I have choice. One thing I've learned is to completely avoid flash drives on any of these sites. 90% of the time, they will fail a good memory test. Seems they use a flash drive 8 or 16 times smaller and flip the bits on the size reporting. They can sell a bunch of these before they are booted off the service. > I never looked at flash drives online. I bought SD cards and at some > time there was flood of fake cards that reported much higher capacity > than they had. But then came programs that tested real capacity > and it seems that problem essentialy vanished. At least for > moderate capacities.Again, not my experience. The vendors got smart and provided their own images of passing the test. I was asked to show a VIDEO of the unit being tested and failing. The test takes some 12 hours or more to run!!! I had to dispute that one on the credit card. I stopped ordering flash on the Internet. I was in Microcenter today, so I picked up another 256 MB flash for $20. It's store brand, so probably not great, but it's actually the right size (minus formatting, etc). -- Rick C. -+++ Get 1,000 miles of free Supercharging -+++ Tesla referral code - https://ts.la/richard11209
Reply by ●February 3, 20232023-02-03
Crap! I posted about this in several forums and got nibbles from a few, including here. I stopped replying because the waters got more murky rather than more clear. So I wanted to wait until I had something more accurate to provide people. I am planning to reply to you too Paul Rubin. I just have some of my own stuff to deal with first. Meanwhile, someone sent a reply by a means I don't recall. He specifically mentioned that he had designed a product in a similar enclosure to what I want. I think he even mentioned it being IP67. But durned if I can find it. EEVBLOG has the worst messaging facility. You get to see the messages coming to you, but not the messages you send. So no conversational context! If this jogs anyone's memory, please contact me again. -- Rick C. +--- Get 1,000 miles of free Supercharging +--- Tesla referral code - https://ts.la/richard11209
Reply by ●February 3, 20232023-02-03
On Friday, February 3, 2023 at 12:22:55 PM UTC-5, Rick C wrote:> Crap! I posted about this in several forums and got nibbles from a few, including here. I stopped replying because the waters got more murky rather than more clear. So I wanted to wait until I had something more accurate to provide people. I am planning to reply to you too Paul Rubin. I just have some of my own stuff to deal with first. > > Meanwhile, someone sent a reply by a means I don't recall. He specifically mentioned that he had designed a product in a similar enclosure to what I want. I think he even mentioned it being IP67. But durned if I can find it. EEVBLOG has the worst messaging facility. You get to see the messages coming to you, but not the messages you send. So no conversational context! > > If this jogs anyone's memory, please contact me again.Nevermind. I found the email. I will be meeting with my brother this weekend to figure out how to proceed. Thanks for your interest. -- Rick C. +--+ Get 1,000 miles of free Supercharging +--+ Tesla referral code - https://ts.la/richard11209
Reply by ●March 22, 20232023-03-22
On Tuesday, January 17, 2023 at 11:24:33 AM UTC-4, Rick C wrote:> The unit only really needs one serial port, but it is more convenient to have two connectors, so I guess it needs to ports. One port will only receive and the other only transmit, no handshaking. > > The function is pretty simple. A sensor sends a line of about 50 chars, at 9,600 bps, once per second. This box counts 20 lines and adds a header. So nothing fancy is required of the MCU. There are parameters set when starting operation. > > The main thing I'm having trouble finding, is this needs to be in a box as a unit, not a board and a box to be assembled. Google hasn't been much help returning all sorts of things that aren't useful. > > Anyone know of such a box? The programming might be contracted out, if you are interested. There's a prototype using an Arduino nano, but some of them are flaky and it would not hurt to start over from scratch.I was skimming the web for this again and I think I found something from Aaeon. Not sure why I didn't find this before. Maybe I did, but at that time was really looking for something with a simple CPU, rather than something to run a full OS. Beggars and choosers... https://eshop.aaeon.com/ultra-slim-box-pc-boxer-6405.html This one is $366, which is more than I'd like, but beggars... It is cheaper than the tailored unit a guy is working on for us. A sample unit doesn't work right and debugging across an ocean is not working very well. I could have this up and running in a day or something, as long as it comes with Linux installed. They have a cheaper unit with a single serial port, $287. https://eshop.aaeon.com/rockchip-android-system-boxer-rk88.html Not sure if there is any real risk to sharing the serial port between the two devices. I know there's no handshaking. In fact, the Arduino shares a single serial port. The only real problem is communications. Aaeon only has a couple each. So far, they have not responded to my requests for delivery on 20 units. BTW, to those who contacted me about this and haven't heard back after the initial exchange, I'm sorry. I got busy with my own work and lost track of the emails. Of those who did reply, only one had a design in a box, ready for software. But that is not yet working. -- Rick C. +-+- Get 1,000 miles of free Supercharging +-+- Tesla referral code - https://ts.la/richard11209
Reply by ●March 23, 20232023-03-23
Rick C <gnuarm.deletethisbit@gmail.com> writes:> BTW, to those who contacted me about this and haven't heard back after > the initial exchange, I'm sorry. I got busy with my own work and lost > track of the emails. Of those who did reply, only one had a design in > a box, ready for software. But that is not yet working.You still want someone to do this custom? What is your budget and how many units do you want? Did you ever find out more about the requirements? I know a good who is good at this stuff. You are probably looking at $1000 or more of NRE, but spread across a few dozen units it might not be too bad, as the hardware itself should be quite cheap.
Reply by ●March 23, 20232023-03-23
On Wednesday, March 22, 2023 at 11:35:18 PM UTC-4, Paul Rubin wrote:> Rick C <gnuarm.del...@gmail.com> writes: > > BTW, to those who contacted me about this and haven't heard back after > > the initial exchange, I'm sorry. I got busy with my own work and lost > > track of the emails. Of those who did reply, only one had a design in > > a box, ready for software. But that is not yet working. > You still want someone to do this custom? What is your budget and how > many units do you want? Did you ever find out more about the > requirements? I know a good who is good at this stuff. You are > probably looking at $1000 or more of NRE, but spread across a few dozen > units it might not be too bad, as the hardware itself should be quite cheap.If you are talking about someone to build a board, no thanks. That is what I meant to say in the post, but I guess I glossed over that. I found a platform that is affordable, even if it is way overkill. A custom board design is not needed. Heck, a custom board design was never needed, except that RS-232 voltage levels are needed at the serial port I/Os. Otherwise, an Arduino of some variation, would be ideal. I will just write the software myself with the $300 platform I guess. Being a PC type platform, running an OS, updating the software is just a matter of copying a file from an SD card or a USB memory stick. It could even be hooked up through the Ethernet port, although I'm not so familiar with that these days. Years ago, I had a couple of desktop PCs running Win2k and from the info I found on the website World of Windows Networking, was able to connect them so the disk drives were available on either machine. I tried to do the same think a couple of years ago and it was much, much harder. Microsoft has made networking much more complex now. I did manage to find my way through management speak and arrive at a very simple set of requirements. In fact, the problem with the guy we currently have working on the effort, is he added requirements of his own, that mess up the operation we intended. We might still use his solution, if he can get it to work for us. But he's in the UK and this is mucking up the debugging. This device goes between a sensor, and an EDAS, which is just an industrial computer acting as an intermediary, collecting other data and sending it all on to other receivers of the data. A product update in the sensor (third party product) changed the data format. Before this new sensor was used, the translator was not needed. The translator makes the new sensor output compliant with the old sensor format which is expected downstream. Serial formats are 9600, 8, N, 1. The input data is 1 line per second, output as soon as converted. A header is appended after each 20th input line. At these data rates, there will be no handshaking and no chance of any collisions. New data format on incoming message example: # 032023 174930 23.024 6.79 17.37 12.44 Terminated with /r/n Old data format on output message example: 01/30/23 19:15:28 21.788 6.23 17.41 12.66 Terminated by /r/n The modifications in the data are removing the "# " at the beginning and inserting '\' and ':' into the date and time fields. Every 20 lines a header should be inserted and sent to the output. If something corrupts the line count, it's not a problem. =========================================== Date Time Temp SpCond pH ODO m/d/y hh:mm:ss C mS/cm mg/L ------------------------------------------- *** 1-LOG last sample 2-LOG ON/OFF, 3-Clean optics *** Anything received that isn't in the input format specified above, should be sent on to the output. No other data should be sent to the output, such as boot messages. The only error checking should be that the line does not overflow the internal translator buffers. A watchdog timer could be used to reset the unit, if the software is lost in the weeds. The goal here is not for any data error checking, or other optimizations. If the old sensor produced any crap data, it didn't muck up the works before, and it shouldn't be a problem now, so just send it on. I don't know for certain that the input data format is always the same length, so this should not be assumed. I would say an 80 character max length is a safe assumption. The /r/n should be the line delimiter. If garbage is received on the input before a message, it will prevent detection of the start of the message, which is fine. As soon as the next /r/n is received, it will be back in alignment. That's all that matters. If I had more free time, I would have this done by now. lol -- Rick C. +-++ Get 1,000 miles of free Supercharging +-++ Tesla referral code - https://ts.la/richard11209
