Ethics of posting schematics

[SteveM732]

Many of the electronics that we use from an ESC to battery chargers use pretty standard circuits so it can be fun and fairly easy to make your own. Part of this process for me is trying to figure out how a popular product was designed then take it apart and try to identify the components and circuit functions.

For simpler devices it is quite easy to trace out the PCB and regenerate the schematic. This schematic is then very useful for troubleshooting a dead device and/or for educational purposes and discussions. But is it ethical to post a schematic for a product currently in production and for sale? Since a lot of the value of electronics today is in the firmware and/or ASIC then it seems to me like a schematic of a fairly obvious design would not be harmful.

[Acetronics]

Hi, Steve

Reverse Engineering is nowadays a common practise.

If you do not want people to know which circuits you use ... just use your own refs or wipe distinctive marks !!! Extra circuitry also is welcome ...

Now, the same scheme can come from two totally unlinked persons ... just consider application examples from the manufacturers.

That's how I found the circuitry of my batt charger ... on its processor manufacturer's site !!! ...
Didn't find the soft ( but not sure one can't re-build it ... from example applications )

Other example, ...

With a friend of mine I've never met and located 1000 km away, we were talking about Diesel sound modules for model boats :

Funny ... our solutions were really close to each other ... for a not-so-simple-a-scheme !!!

So, Shortly said, Copyright is something for fair people ... you respect other's work or not ... it's your own decision.

For simple designs, it's simple to find a functionnally equivalent ... so, hiding a small bit of work may be more expensive than lowering the production cost !!!

Other people will always be able to copy a product ... one day or the other.

For the end ... I know plenty of students trying to make "little money" by assembling schemes and projects got from the Internet or books.

What to do with them ???



But is it ethical to post a schematic for a product currently in production and for sale



is it ethical to sell a circuit 10 times ( or much more ! ) what its costs ... just because you're the only one who sells it ???

same question ... don't you think ???

Alain

[andrew b]

I downloaded the circuit diagram for my old analogue multimeter, a radio shack "range doubler" from 20+ years ago, I am so glad that someone posted it to help me identify the fault. (an O/C resistor)

[village_idiot]

Most of the stuff in use today comes straight from the application notes with very little refinement.

[andrew b]

Got to say, most stuff I have taken apart seems to be *VERY* similar to the manufacturers application notes.

[SteveM732]

Thanks for your thoughts and comments. I agree that the product I took apart (one of those watt meters with a shunt resistor) is so simple that I would have build it very similarly had I been tasked to design it with no idea how this one was designed. In fact, they used my favorite brand of microcontroller. But much of the work is in the firmware too and no amount of probing will reveal the source code (which is something most likely copyrighted).

I do not wish to copy the PCB or the code and have no desire to make any money off it. Besides, I think they should have done at least two things differently and would not want a copy. If anything I'd want to make a watt meter with open source hardware and firmware, but I don't want to do it in a way that makes it look like I stole the circuit (even though it could have walked right out of an app note and the firmware cannot be copied).

[Malc C]

Copying firware is one thing, copying a schematic is another. If you look at most of the basic USB tx to pc type interfaces they all used the same OTP PIC, and thus much of the supporting descrete components were all the same, with the same schemaitic. However it was the code in the chip that gave you an XTR interface or a generic Windows Joystick interface. Whilst the latter has been made public on several sites, there are certain ethics in either obtaining the orignal XTR code, or working out the encryption and then writing your own version.

The problem you'll find is that electronics being what it is, to do a function you have to use a group of components, and that can't be changed, (darlington pairs, or potential dividers for example) so you have no chioce but to "copy" the same functionality.

[village_idiot]

And agian a lot of this stuff is built from sample code provided by the chip manufacturer to get you to buy their chips over someone else's. SO if you want to make something, it pays to look for app notes on the subject, a lot of work may have already been done.

[dleroi]

What I think is unethical is the manufacturer NOT supplying a schematic. When something of mine breaks I want to fix it - not send it back to the factory for who knows how long. That's a major reason why I'll spend more than an item would cost to build it myself.

- Don

[JohnMuchow]

Problem is that supplying the schematic opens the manufacture to slew of possible lawsuits from those who use the schematic and destroy the device, hurt themselves, or burn their house down. And those lawsuits will come, no doubt about it.

In addition, IMHO, 99.999999% of the purchasers who purchase the device will never need the schematic and will only wonder why the manufactirer forced them to pay for its inclusion and why the manufacturer is trying to either impress them with useless techn-babble or confuse them as to its purpose or utility.

For those of us who could actually use the schematic, the manufacturer would still not want to supply it as that still opens them to lawsuits. In addition, there would be questions from us to their engineers about things in the schematic and about how to repair a device after already making failed modifications/repairs. Answering the questions opens up that lawsuit thing and not answering them makes the manufacture look like they won't supoprt their users. And the last thing those engineers would want to do is answer our questions.

There are almost no good reasons for a manufacturer to include a schematic with their product, as much as I'd like them too. :)

[SteveM732]

Problem is that supplying the schematic opens the manufacture to slew of possible lawsuits from those who use the schematic and destroy the device, hurt themselves, or burn their house down. And those lawsuits will come, no doubt about it.

In addition, IMHO, 99.999999% of the purchasers who purchase the device will never need the schematic and will only wonder why the manufactirer forced them to pay for its inclusion and why the manufacturer is trying to either impress them with useless techn-babble or confuse them as to its purpose or utility.

For those of us who could actually use the schematic, the manufacturer would still not want to supply it as that still opens them to lawsuits. In addition, there would be questions from us to their engineers about things in the schematic and about how to repair a device after already making failed modifications/repairs. Answering the questions opens up that lawsuit thing and not answering them makes the manufacture look like they won't supoprt their users. And the last thing those engineers would want to do is answer our questions.

There are almost no good reasons for a manufacturer to include a schematic with their product, as much as I'd like them too. :)
That's all good info, but not quite what I was asking about. But I don't agree that manufacturers don't include schematics, I purchased a Sony Trinitron CRT monitor about 8-10 years ago that included a schematic. I think we all know what kinds of fun voltages are in those. My car shop manual has a full set of schematics, etc etc. But yes, most hobby level equipment is schematic-less, a pain in the butt in a recent thread where someone accidentally applied 36V to their charger inputs.

I'm not done going over the schematic, double checking it, but when I do I think I will post it here as see how it goes.

[JohnMuchow]

I agree, there will always be exceptions. :)
But I think the overwhelming majority of manufacturers won't include schematics and actually make it hard for someone to get them.

Regarding that schematic posting...
Do you mean that watt-meter you mentioned earlier in the thread?

[SteveM732]

Regarding that schematic posting...
Do you mean that watt-meter you mentioned earlier in the thread?
Yes, but there may be a slight delay as I am having to flush the water cooling system on one of my computers instead of going over the schematic I drew.

[jeffs555]

Don't know if they are still around, but in the old days when people actually repaired radios and televisions, Sams Photofact was the source for schematics and repair information. All of their manuals and schematics were done by reverse engineering without input from the manufacturers.

If you were to post a copy of schematics supplied by a manufacturer, you would be violating their copyright. If you independently create a schematic even by tracing their circuit, I am pretty sure you are not.

[SteveM732]

Don't know if they are still around, but in the old days when people actually repaired radios and televisions, Sams Photofact was the source for schematics and repair information. All of their manuals and schematics were done by reverse engineering without input from the manufacturers.

If you were to post a copy of schematics supplied by a manufacturer, you would be violating their copyright. If you independently create a schematic even by tracing their circuit, I am pretty sure you are not.
You know, I remember several years ago when our TV died my dad went to the public library and got a schematic for it from some book, must have been Sam's Photofact or similar. Any how, using it he was able to repair the TV and still uses it to this day.

Well then, since there seems to be nothing "wrong" with me reverse engineering the hardware and posting the schematic then I will do so. The product in question is a Watt's Up meter (http://www.rc-electronics-usa.com/electrical-test-equipment.html) made by RC Electronics. It is rated 4-60 volts and up to 50 amps continuous current.

I have attached some pictures and a schematic. Some comments I have on the schematic:
- Instead of R13 I would have used an inductor
- C1, C2, and C6 are 0805 and 1206 but I have no idea what capacitance they are, the other capacitors are mostly decoupling caps so I assume 0.1 uF
- Pin 2 of J1, the serial programming connector, should be connected to VDD and not the unregulated input voltage
- The PCB appears to have seen several revisions so J1 may have been there only for development and not used for production programming
- The microcontroller does not respond to my stk200 programmer, I suspect the lock bits are set and possibly parallel programming was used to disable the SPI

So as you can see, I have no idea what the firmware looks like and there are a few unknown capacitor sizes, but that does not matter to me as my goal is to make my own meter with equal or better capabilities with open source hardware and firmware.

Your comments and suggestions are welcome.

[AndyKunz]

I always tell my kids, "When in doubt, don't. If you have to ask - it's because you're conscience knows it's wrong. Listen to your conscience."

Andy

[Acetronics]

So as you can see, I have no idea what the firmware looks like and there are a few unknown capacitor sizes, but that does not matter to me as my goal is to make my own meter with equal or better capabilities with open source hardware and firmware.

Your comments and suggestions are welcome.

Hi, Steve

The problem is simple:

To reach your goal You need :

1) voltage
2) Current
3) Elapsed time.

"sticking" together all you can find on the datasheets, Application notes and various Forum posts it will be easy for you to make your own design and program.
not forgetting your own work ... of course :rolleyes:

Every part of the design ( and the soft ) already is " open source"

No need to talk about "ethics" here ... else than just think to thank all people and societies having given you ideas.

The one and only headache for you will be to choose which processor you'll use :D :D :D

May be also the LCD Backlight colour ... :p


Every one ( or most ! ) know:

Power = Voltage * Current
Energy = Power * Time

... ;)

Alain

[SteveM732]

Thanks Alain, I was pretty sure there was nothing ethically wrong with posting the schematic, but I wanted to check to see if I had overlooked something obvious. If I really thought there would be a problem I would not ask a question on the RCGroups, I would seek professional advice.

The microcontroller will be an Atmel of some kind, I have a variety of reasons why, the biggest being cross-platform gcc support. I hadn't thought of the back light yet, I was still thinking about integration methods.

Time to go fly!

[Ralph Weaver]

Check this out:
http://www.circuitcellar.com/avr2006/winners/DE/AT3011.htm
http://www.circuitcellar.com/avr2006/winners/DE/DE_Abstracts/AT3011_abstract.pdf

or prebuilt
http://www.magtechinc.net/Hibox.htm

[JohnMuchow]

So as you can see, I have no idea what the firmware looks like and there are a few unknown capacitor sizes, but that does not matter to me as my goal is to make my own meter with equal or better capabilities with open source hardware and firmware.

Your comments and suggestions are welcome.Well, you can always takes the "classic" path and purchase (or even borrow) one of each logger that you can find, check them out, take the best of each design, and then create your own.

IMHO, forget about creating another PC-side logging/graphing package and look into using already existing software like LogView. This will significantly reduce the time you'll need to suport users. You'll then be able to concentrate on the firmware and hardware...form factor, component cost, accuracy, calibration, ease of repair, stocking of bare PCBs or kits for sale(?), safety concerns (shrink wrap around PCB or case?), etc.

For example, the BVE sense resistor that the Watt's Up and one other meter uses is pretty nice but tough to solder and even tougher to find (to purchase) in the US. Do you use that one, or another? Lots and LOTS of those kind of decisions to make. :)

John

[SteveM732]

Ralph, thanks for the links to the HiBox, itis nice to see how someone else constructed a meter too. I see he provides a schematic, BOM, and source code, but no gerbers much less the EDA source files for the PCB.

John, if I could afford to buy every meter/logger out there I'd have little desire to try to build my own, but I hear what you're saying.

I do not intend to make a product for sale though it will be available to the public (meaning all source files and code but now hardware except possibly the PCB). It looks like it is time to create a build log for my project!

[JohnMuchow]

Ahh, I misinterpreted. For me though, every time I do a project of this scope it always ends up costing much more than I could have bought a couple of commercial units for! :eek:

But that isn't nearly as as satisfying. :D
This open-source unit sounds great! I'm looking forward to seeing what you put together.

John

[SteveM732]

Ahh, I misinterpreted. For me though, every time I do a project of this scope it always ends up costing much more than I could have bought a couple of commercial units for! :eek:

But that isn't nearly as as satisfying. :D
This open-source unit sounds great! I'm looking forward to seeing what you put together.

John
When you consider how much could be learned from tearing apart several commercial units, it would be a cheap education.

And yes, in the end I will buy my parts 1-2 at a time and will have to pay shipping costs and what not and before you know it I'll have paid more than the $47 or so that the Watt's Up meter cost me. But I will have learned even more, and hopefully the next guy can make one for cheap, and may even learn a little from seeing what I went through to make it work.

In case you haven't found it yet, I started the build log over here (http://www.rcgroups.com/forums/showthread.php?t=901827).

[Ralph Weaver]

True enough, but as I suspect you know, there are several free PCB programs out there and it wouldn't take more than a few hours to have a gerber. Also, some PCB houses will take GIFs. Back when I first started doing PCB's we used tape.

[QUOTE=SteveM732]Ralph, thanks for the links to the HiBox, itis nice to see how someone else constructed a meter too. I see he provides a schematic, BOM, and source code, but no gerbers much less the EDA source files for the PCB.QUOTE]

[SteveM732]

And without further ado, here is the CellPro 4S circuit board sans LCD (high res version available on request), schematic, and reassembled with back lit LCD screen ala Phoenix-RC (http://www.phoenix-rc.com/products/wbkit.php).

No more tilting the charger to see the display! :)

[SteveM732]

For some reason I always thought my CellPro 4S was charging each cell individually since it was doing the charging through the balance taps. I realize that this was a silly assumption and I should have known better. Now that I have studied the schematic a bit I can see that the positive end of the pack is connected to the output of the switching regulator and the negative lead of the pack is set to an appropriate voltage below that. Then Q1 - Q4 are used for balancing the cells. Exactly how I am still trying to figure out as the source and drain seems to be backwards for Q2-Q4 and Q4 not having a very low impedance path to dump the excess current. Obviously it must work and I am just not seeing it yet, any thoughts on how the balancing works?

Just goes to show you want all you can learn from a schematic.

[xtal]

I thougt my charger went south... Since it acted the same on 3 of my ups batteries...

So I reverse engineered the schematic..

This is what I came up with....

I lated figured out I had 3 bad batteries [ after trying it on a known good battery ]

The 2n3904 and 3906 are really 2n4401 and 4403

edit attached corrected schematic ,,,may still not be 100%

[arocholl]

IMHO, forget about creating another PC-side logging/graphing package and look into using already existing software like LogView.

Now that you mention LogView...
This software doesn't work anymore, right? At least this one here http://www.logview.info/joomla/index.php?option=com_frontpage&Itemid=1&lang=en


It display everything in German (even if you choose English) so I am not sure but it ask for some license file, ask for IBAN account and, if not provided, close itself.

Weird. Nice idea and product that become useless before being really available...

[moelski]

Hi !

Please go to the new download page at www.logview.info.
Download here: http://www.logview.info/cms/d_logview-21.phtml

Download the 2.3 version and install it. You can set the language to english and until now the most is translated to english.

If you have any trouble feel free to contact us directly at dominik ÄTT logview DOT com.

Greetz Dominik
www.logview.info