Seems you are 25 years to late. But this company is still selling its device (with a Z180 processor). Seems this is what you are asking for (but maybe without the price):
I bought many things from Aliexpress an nearly never had any problems.
I'm pleased for you. People safely cross streets outside the crosswalk, yet people are killed doing that every day. Do you tell your kids it's a good thing to do?
Buying a $10 or a $100 thing at aliexpress is not that similar to getting killed, you know. I have bought a lot of small stuff there and have not yet been killed. Oh yes, and I do cross streets as I please and I am still alive, but that's not a very similar matter, as explained above.
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.
I am not sure I'd bother to open a $10 dispute on aliexpress, I'd expect your outcome plus wasted time. I can't remember buying anything which costs > $100. They try to keep their reputation (aliexpress, not alibaba) as they make their money on huge sale quantities of small value all over the planet. Recently I bought a nice keyboard at something like $40+, can't believe I got something *that* good at this price (way better than the Cherry-G84-s I have been using for decades now). On alibaba the risks are way higher I guess, depends on luck. My sister buys stuff from someone in Pakistan she found over alibaba and she is happy (many years now). No surprise your experience has been different. I would not consider buying chips on either alibaba or aliexpress of course. I bought some fast HV diodes on ebay twice and what I got was not just OK but unobtainable otherwise.... Go figure, life is colourful and full of risks of various probabilities and stakes.
Rick C snipped-for-privacy@gmail.com wrote:
IIUC Alibaba is intended for larger transactions and has different rules than Aliexpress. I did only small or very small transactions. For me problem with Ebay was that with cheap shipping things would not arrive and there were no way to dispute this. I can understand this, without tracking there is no way to know who was to blame: seller, mail or fraudolent customer. Tracked shipping was significantly more expensive than goods that I wanted to buy. OTOH things with cheap/free shipping ordered on Aliexpress were arriving fine. So my conclusion was that Ebay sellers were at fault and I stopped buying on Ebay.
There was period when also some shipments from Aliexpress vanished, but AFAICS Aliexpress got this under control: they have reasonably cheap tracked shipping and it seem that on all shipments they track if package leaves China. That probably removes all incentives for sellers to fail sending things.
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. 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. 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. 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.
BTW: classic Arduino boards are supposed to have Atmega 328P. I have heard that recently a lot of boards instead had Chinese chip. IIUC such boards also appeared in western distribution channels, so it is possible that some Arduino boards that you use is equpped with Chinese chip. On paper Chinese chip should be better than Atmega 328P, but it has incompatiblities. For simple use in Arduino it may be compatible enough, but in case of troubles difference between chips is one of possible reasons.
I've had exactly that problem. The only issue is that the vendor will ask you to wait another week or two, and repeat that process until the 60 day window has closed. So I say, no, I want a refund. Even if they don't cooperate, Ebay has always provided a refund. This has happened maybe four or five times. Once, the ordered item really did arrive.
The shipping on Ebay has improved. Very few of the vendors now use untracked shipping. But even if the tracking says it was delivered, you can still get a refund for an undelivered item. The shipping company does not always deliver to the right home or mailbox. Sometimes people give it to you, other times they don't. In any event, again, I've never been turned down for a refund by Ebay if I do everything right that I'm supposed to do, which is mostly, report it within 60 days of ordering.
Once a Japanese company shipped an item wrong. I don't recall the detail, but they wanted me to pay the return shipping which was not cheap. I dug my heals in and eventually lost. Don't recall the reason why. They stopped receiving my emails, or any other communications. So I opened another account, ordered the deluxe version of the same thing, shipped to another address. I made a claim with the credit card and got the refund. Then I sold this one to pay for the loss on the other one. Maybe that was dishonest, but I feel I was cheated on the first order, so justified.
I also ordered a Hantek attached oscilloscope, the low end model, to evaluate before buying a higher end model. I couldn't even get the software to load. No support to speak of, so I put in for a return. For whatever readson, the tracking was mucked and said it was never delivered. So I got the refund without an argument. Hantek is real crap goods, btw.
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.
LOL! If they buy counterfeit ICs at $0.05 each, they don't need to sell many at $5.00 to make profit.
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.
Sure, if you only need crap components, then you are good to go!
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. 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 don't have details, but I'm pretty sure they are using an actual Arduino nano from the original Arduino vendor. You'd think they are buying from mainstream vendors, no fakes.
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.
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.
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. 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.
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).
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.
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
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.
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.
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).
If I had extreme requirements, then I would not use 2N3904 or BC237. But they are good enough for most uses.
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).
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.
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.
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.
Alibaba doesn't work that way.
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.
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.
Dear god! It was just a number to illustrate the idea. Pick you own numbers.
Ok, buy your transistors at Alibaba. Just don't buy anything that requires some real money.
Ok, so you actually want 2Nxxxx and don't care what you really get. Fine.
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.
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.
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).
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.
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...
They have a cheaper unit with a single serial port, $287.
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.
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/nThe 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
The number of units required is initially 20, and probably another 20 in a few months. After that, not sure.
We've been here before, but there are many many 'mini PCs' (often Celeron or similar low power CPU) coming out of China that have multiple RS232 ports. There doesn't seem to be much special about this one.
If such a 'mini PC' is within your spec (you were talking about microcontrollers originally), it's just a case of finding a distributor who meets your requirements. Easiest is to just go on Aliexpress [1] and buy them, but if that's not your thing then I'm sure there is a US/wherever importer.
If you're going to need many years worth of supply that's a bit trickier, since they tend to update the product lines every time Intel releases a new chip.
Theo
[1]
No, building a board would be crazy unless you're making 1000s of them. Pick an Arduino or similar board with RS232 support, pick some enclosure out of a catalog, put the stuff together, get the code running on the board and test everything, etc. Then send the assembled unit to the actual deployment site for in situ testing before making more units.
There is always some stuff going wrong or consuming time in any process like that. Thus there will be some NRE.
You are really willing to spend $300 per box in that quantity? So $6000 or $12000 depending? This sounds very doable.
Where is the deployment site geographically?
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