I have a Relay Output Board with 16 three Amp Relays on it.
Ill get a picture of it in a few hours. (My son has my camera)
Right now it is prewired for address 2 & 3. We needed it for a specific project.
I am redoing the pc board to include a dip switch for addressing.
more info in a bit.
Something like a board with a couple of 74HC595 chips on it with MOSFETs driven from the outputs? It would be quite easy to make something like that for yourself if you can't find one. What are the MOSFETs switching? If it's only 250 mA continuous or 1.5A pulsed you could simply use a couple of TPIC6595 chips.
Leon
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
Paclyne, the title doesn't say it "all"... what kind of current/switching speed/voltage/etc. etc., are you looking for? A board can be made fairly easily, but we need to know what it is you want.
And what does this "about 10" mean? Are you saying 10 switches? $10?
I have a need for {about} 10 x 12{ish} volt DC outputs. These outputs will {mostly} drive solenoids, speed is not a real issue they switch about 1/second. It is anticipated that no more than 5 or 6 outputs would be on at any time...
A FET board would be nice (though relays would also suffice).
SPI/I2C interface would be excellent as well.
I'm after a seperate board so as I can swap it out should the magic smoke come out on site... wouldn't need to be more than 1 meter away from the main processor..
paclyne, so, basically a PCB with 10 FETs mounted on it, with screw terminal outputs? Could the input be a simple serial to parallel expander? I imagine some optical isolation would be in order since you talk about frying the board?
I don't know if such a thing exists, but what you're talking about could be made for about $20-$25 total. Let me know if you'd be interested. I'm looking for PCB's to make myself for experience, so this might be a cool thing to make.
EDIT: That's with all the parts on the board, not just the PCB itself.
Post Edited (Philldapill) : 5/28/2009 6:08:00 PM GMT
At least I know that I can try to get help with clarification and not have to worry about making sure I get every detail right before I ask questions. It must be wonderful to be Leon and already know so much. I find his attitude does the hobby a dis-service (I have encountered him on other boards..). He may be quite a nice person, but sometimes his coments..........
I would prefer Mosfet outputs, They will be mostly controlling solenoids, but as the project develops (and depending on what the end user's preference is) they might be used to control other methods (swiching a small electric motor). I can not define exactly what will be switched. The peference is solenoids, but it depends on what is most easily available to the farmers
Typically the 'outputs' would be controlling 12VDC, but 24V would also be possible (probable?). Now those voltages are nominal, 12V design - might actually be 9.8 V when all plumbed up, or 24V may float as high as 27.6 V due to the way the batteries have been charged
I have had some expirence with I2C but didn't want to limit my options too much. Hence my original SPI/I2C comment.
At this satge we need 10 outputs, however {again} I didn't want to limit my options too much as perhaps there were 16 channel cards out there, or 6 channels (where as I would combine two units).
The probelm with relays is that they draw additional current when energised (unless I use latching ones) and as these sites will be remote and utilise solar power to charge it's batteries I assumed (I'm sure Leon would know already) that mosfet would be a better fit - Please enlighten me if I'm wrong - I ask questions and hope to get information..
The problem is that I don't know what I don't know. Nor do I know _exactly_ what information would be relevant to my quest.
You haven't said how much current you will be controlling on those outputs! That's the cause of my exasperation. Are they big solenoids or little ones? Establishing that will tell us whether or not you need MOSFETs, how beefy they need to be, and whether they need drivers. If you had mentioned it in your first post we'd have had a solution for you the same day, instead of spending a couple of days faffing around!
Leon
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
Just want to add my 2 Cents worth. ( or half a shilling in the UK?).·Im not siding with anyone, just some suggestions to help make this forum work more efficiently.
In your first posting if you had asked about driving solenoids operating at 12-24 volts DC and, that had to run from limited solar power we would have come up with better suggestions.
The title didnt say it all.
It is wasteful of everyones time to have to pull teeth to find out what you want.
It is like teloling your mechanic 'My car is broken. How much will it cost and when can I have it back?' Not much info to go on.
Dont get me wrong, I like helping out on the forums, but being self employed my time is limited. Im sure others have the same problems.
When in doubt, add all the parameters of your project, and your objectives. It can only help, and it will reduce friction.
What is the project you are building? A solar powered sprinkler system at a golf course?
If it is a secret project then this forum is not a good source of information. We all learn from each other and I dont know it all (Yet!)
Anyway, how much current does each solenoid draw while energizing and what is the holding current?
I have used SPI and I2C on stamps and find the I2C to be easier to impliment (Using a 2P stamp).
The relay board I suggested draws about 10 MA per relay and can switch 3 Amps at 30 VDC. This is still borderline for solar power operation though.
If you are using solenoids with 100 ma pull in and 50 ma holding, the relays use too much power.
If the solenoids have·1 amp pull in and 500 ma holding current, then the 50-60 ma used by the relays is almost negligible.
My copy of firefox has spelling error detection in it when I enter any text in the forums. All errors have a red underline. Don't know about other browsers or OS though.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"VOOM"?!? Mate, this bird wouldn't "voom" if you put four million volts through it! 'E's bleedin' demised!
Paclyne, sometimes it seems that some forum members are being a little rude, but you may want to take this into context. Many members, such as Leon, are extremely knowledgeable, and their is only so much of their time to go around. It is best to provide MORE information than needed. If you chop your post into paragraphs with distinct points, the reader can sometimes save time by skipping over some parts, and getting to the real meat of the post. It only takes an extra minute or so to give much more information, and you are more likely to get good solid replies.
If you assume the reader already knows what you are talking about, then you might get replies such as these - "gently" asking for more information.
Believe me, I've learned this from my own personal experience, so this isn't meant as a critique, but just a tip.
Now, as for the board, your specs should be easy to do. The question is how much power this will all take, and I'm guessing the final board(mosfets/interface circuit) could be done to consume ~10mA continuous current, maybe a couple mA less. That's just a rough estimate, but take it as a pretty good one.
The MOSFETs I have in mind may be overkill, but they are pretty cheap. I'm sure they can handle whatever you throw at them. They are rated for 55V, and 80A, but from my experience they can do 10A continuous with only a little heat. They also have built in Zener diodes, so the inductive kick from the solenoids won't be a problem.
Datasheet: http://pdf1.alldatasheet.com/datasheet-pdf/view/171111/STMICROELECTRONICS/STD60N55F3.html
As for the interface circuitry, I'm still looking but I've got a couple 16-bit shift register chips from TI in mind. If you want me to look into this and start a design, let me know. Remember, I'm looking for practice.
The original post wasn't meant create a storm bigger than Ben hur, It was supposed to invoke a few quick web links (as all my searches had turned up a blank) so as I could follow them and decide if any were suitable.
As far as the solenoids, they are designed to switch 6mm air hose line, so they aren't samll but I really don't know how big solenoids get. I would anticipate about 150 -> 250 mA hold in current each, but I have no definite figures on this.
And as they are in use on farms, should one fail they would be likely to be replaced with whatever the farmer has handy in their shed (that old solenoid salvaged from a tractor for example)..
And as far as spelling, I too use firefox and am familir with the wavey red line. But they don't appear in this forum (thus all my spelling must be perfect - no?). Perhaps their is something special I need to in order to get it working again in this forum?
Perhaps you have more disposable income than me, or perhaps you _always_ work alone? I have neither of those two luxuries.
My I suggest that if you are counting the days and could have done it better, then perhaps you should not bother with reading my forums posts anymore, as obviously you stand to gain no knowledge from my fumblings.
But, for the record, These units will be retrofitted to several existing installations and I have not been able to contact the relevant farmers to check exactly what they are using. Nor have I been able to speak to the field guy to see if any of the existing valves we are trialling have failed or if one particular brand has out-performed the others. Communications to some parts of Australia can provide difficult..
The last I heard the SMC valve block was working well, but that was over a week ago...
Can the current draw matter that much? Surely one 6mm solenoid valve draws about the same current as another (I'm sure there are specialist valves that draw different currents, gut not the bog standard types). Wouldn't any design be made to cope with {say} upto 2A draw per point?
Hence, my original post was just an ask for links to pre-canned boards (then I could work on the code - not on the 'interfaces'). I will concede that my original post wasn't particularly well phrased.
I, and everyone else, don't seem to be learning much from your fumblings, let alone gaining anything!
You were very unclear about what it was you were trying to do! It now seems that you are designing a controller and drivers that are going to be retrofitted to existing solenoid valves. What is the specification of those valves? You originally mentioned 150mA - 250 mA current, you now say it is up to 2A!
I very much doubt if you will find a COTS board with 10+ outputs that will do what you want, you will probably have to design it yourself or get someone to do the work for you. I'd simply use two 74HC595 chips (they are SPI-compatible with eight outputs each), MOSFET drivers and suitable 2A MOSFETs.
Leon
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
Oh, guys come on... Leon is a very capable help when you ask the right questions...
As for your design, paclyne, I think I know what you are after. Like I said, if you want a board, I can whip a couple up for you - "pre-canned". The software should already be written. There are objects for "serial to parallel" chips, which I think I'll be using. This would be the objects used for this board - nothing more except the usual overhead code. The board would have 16 outputs, capable of well over 5A each.
Now, does that sound like what you are after?
(please, guys, no more bickering...)
On retrofitted solenoid valves it can be powered with =V and ~V that give You problems to drive it with MOSFET.
Only solution is to have driver PCB with micro relay's.
To drive that PCB You can use 74hc595 else I2C Expander's.
If You know that it is =V only and drive curent is no more that 500mA You can use ULN2803A Darlington drivers in place of micro relay's.
But it is not many that PCB's You can buy, You must produce them
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔ Nothing is impossible, there are only different degrees of difficulty. For every stupid question there is at least one intelligent answer. Don't guess - ask instead. If you don't ask you won't know. If your gonna construct something, make it·as simple as·possible yet as versatile as posible.
Philldaphil - Thanks heaps for your offer, but I won't take you up on it (especially after Sapieha's suggestion) I realised that Solenoids could be driven from sinking or souring, but I wasn't aware that that could pose problems. Perhaps mosfets are less suitable than relays in this application.
I now know where I can locally get a 8 point relay card (i2c) and will buy some of them. Means I'll have to pull a bit more current (keeping the relays energised, but I'll cope with that. That way I can provide more
We already have several working prototypes in the field (they are running on PLCs), but these are massive overkill {and cost} and have to have additional dedicated external equipment doing other stuff {RFID reading, load cell analysis, etc}. Hence the desire to move to a more embedded solution, then we can gradually phase out the other expensive bits, this is where the Prop shines.
The code I was talking about was moving the PLC code from ladder to spin, the plan was to utilise some of the excellent objects on the exchange for the 'clever' device driver code.
I will try and be more concise in my first postings, as I have tried to explain - I did not meant this to be bigger than Ben Hur.
You will only have problems using MOSFETs with AC, as Sapieha mentioned. I don't see what sinking and sourcing current has to do with it. Are the solenoids AC or DC? If they are AC you could use solid state relays instead of the old-fashioned ones, they can be driven directly from the 74HC595s. Even after five days we still don't really know what you are after!
BTW, how are "disposable income" or "working alone" relevant? I would have this prototyped and working in a couple of days - I'd get the parts the day after I'd ordered them. In the meantime I'd have designed a simple PCB and made it. An hour or so after the parts arrived the next day I'd have the board populated and be testing it.
Leon
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
I admit I haven't read every post here (did someone say something about limited time on the forum?), but I thought I would show off a picture of a PCB I got in a couple days ago that may apply. The PCB has a Propeller on it and 24 MOSFET I/Os and DMX-512/RS-485 and a couple user interface LEDs and an encoder. Attached is a picture. I have the parts coming in Monday or Tuesday to solder it up and test it. My intention for this design is LED control, but obviously the n-channel mosfet channels could be used for a variety of other things.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Timothy D. Swieter, E.I. www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, 3.0" LCD Composite video display, eProto for SunSPOT www.tdswieter.com
how'd it turn out? I jumped right to your site when I saw this *very* smart idea for a prop card. This has TONs of control applications!
What ampacity will the MOSFETs you plan to stock on it have?
> DMX/RS-485 ... encoder
Encode? I'm assuming the obvious - that the DMX will DEcode to control the I/O, right?
Do you have those routines canned into the Prop already? ... it wouln't be too difficult, if not.
Man, I would have broken down your doors to have one of these some years back for stage lighting and effects control (but that was WAY before even the Prop was around.)
cheers,
Howard
(PS Hope your move to Singapore went well --- I've made several overseas moves too --- including one where we thought our stuff went overboard into the Atlantic Ocean [noparse]:)[/noparse]
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
No matter how much you push the envelope, it'll still be stationery.
Thanks guys for checking in. I have the parts to populate a test board, however I have not had time. This past week has been crazy with the moving and work and next week is even worse with a short trip to South Korea.
I think my words may have confused you Howard, let me try and rephrase what I said about the hardware.
There are three user interface LEDs - two are attached to I/O and one is attached to power. (note these two LEDs share the Tx/Rx line of the Prop Plug - we will see how this works in testing)
There is a user interface knob, which is an encoder, for doing any settings or adjustments (firmware is yet to be written that will dictate how the knob is to be used)
There are 24 MOSFET outputs. The MOSFETs are the ICs you see flanked on each side of the product with some heatsinking for the bottom of the IC. The MOSFET is an n-channel MOSFET with a rating of 30V and 7.5A, the data sheet is here: www.fairchildsemi.com/ds/FD/FDS6910.pdf
There is a RS-485 driver connected to the Propeller for receiving RS-485/DMX-512A. The lines for receiving data are not connected, though could probably be jumpered.
I want to create a full featured firmware, not just demo programs. The firmware will include DMX-512A receiving, controlling the MOSFET channels and setting address information. There may even be a stand alone cycling of the channels for testing or stand-alone operation.
I will probably start a new thread on this specific device once I get back to testing. I will try to bump this thread with a link.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Timothy D. Swieter, E.I. www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, 3.0" LCD Composite video display, eProto for SunSPOT www.tdswieter.com
pacman
Posts: 327
Comments
Ill get a picture of it in a few hours. (My son has my camera)
Right now it is prewired for address 2 & 3. We needed it for a specific project.
I am redoing the pc board to include a dip switch for addressing.
more info in a bit.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Alan Bradford
Plasma Technologies
Canaan NH 03741
www.plasmatechnologies.com
Leon
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
Post Edited (Leon) : 5/27/2009 12:15:26 PM GMT
http://focus.ti.com/docs/prod/folders/print/tpic2810.html
·
And what does this "about 10" mean? Are you saying 10 switches? $10?
I have a need for {about} 10 x 12{ish} volt DC outputs. These outputs will {mostly} drive solenoids, speed is not a real issue they switch about 1/second. It is anticipated that no more than 5 or 6 outputs would be on at any time...
A FET board would be nice (though relays would also suffice).
SPI/I2C interface would be excellent as well.
I'm after a seperate board so as I can swap it out should the magic smoke come out on site... wouldn't need to be more than 1 meter away from the main processor..
Hope that clears it up..
Leon
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
I don't know if such a thing exists, but what you're talking about could be made for about $20-$25 total. Let me know if you'd be interested. I'm looking for PCB's to make myself for experience, so this might be a cool thing to make.
EDIT: That's with all the parts on the board, not just the PCB itself.
Post Edited (Philldapill) : 5/28/2009 6:08:00 PM GMT
Leon
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
At least I know that I can try to get help with clarification and not have to worry about making sure I get every detail right before I ask questions. It must be wonderful to be Leon and already know so much. I find his attitude does the hobby a dis-service (I have encountered him on other boards..). He may be quite a nice person, but sometimes his coments..........
I would prefer Mosfet outputs, They will be mostly controlling solenoids, but as the project develops (and depending on what the end user's preference is) they might be used to control other methods (swiching a small electric motor). I can not define exactly what will be switched. The peference is solenoids, but it depends on what is most easily available to the farmers
Typically the 'outputs' would be controlling 12VDC, but 24V would also be possible (probable?). Now those voltages are nominal, 12V design - might actually be 9.8 V when all plumbed up, or 24V may float as high as 27.6 V due to the way the batteries have been charged
I have had some expirence with I2C but didn't want to limit my options too much. Hence my original SPI/I2C comment.
At this satge we need 10 outputs, however {again} I didn't want to limit my options too much as perhaps there were 16 channel cards out there, or 6 channels (where as I would combine two units).
The probelm with relays is that they draw additional current when energised (unless I use latching ones) and as these sites will be remote and utilise solar power to charge it's batteries I assumed (I'm sure Leon would know already) that mosfet would be a better fit - Please enlighten me if I'm wrong - I ask questions and hope to get information..
The problem is that I don't know what I don't know. Nor do I know _exactly_ what information would be relevant to my quest.
Thanks for your help
Leon
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
Post Edited (Leon) : 5/29/2009 11:12:05 AM GMT
In your first posting if you had asked about driving solenoids operating at 12-24 volts DC and, that had to run from limited solar power we would have come up with better suggestions.
The title didnt say it all.
It is wasteful of everyones time to have to pull teeth to find out what you want.
It is like teloling your mechanic 'My car is broken. How much will it cost and when can I have it back?' Not much info to go on.
Dont get me wrong, I like helping out on the forums, but being self employed my time is limited. Im sure others have the same problems.
When in doubt, add all the parameters of your project, and your objectives. It can only help, and it will reduce friction.
What is the project you are building? A solar powered sprinkler system at a golf course?
If it is a secret project then this forum is not a good source of information. We all learn from each other and I dont know it all (Yet!)
Anyway, how much current does each solenoid draw while energizing and what is the holding current?
I have used SPI and I2C on stamps and find the I2C to be easier to impliment (Using a 2P stamp).
The relay board I suggested draws about 10 MA per relay and can switch 3 Amps at 30 VDC. This is still borderline for solar power operation though.
If you are using solenoids with 100 ma pull in and 50 ma holding, the relays use too much power.
If the solenoids have·1 amp pull in and 500 ma holding current, then the 50-60 ma used by the relays is almost negligible.
Ill get off the soap box now,
Alan Bradford· N1YMQ
Plasma Technologies
Canaan NH 03741
www.plasmatechnologies.com
I wish there was a spell checker on this forum!
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Alan Bradford
Plasma Technologies
Canaan NH 03741
www.plasmatechnologies.com
My copy of firefox has spelling error detection in it when I enter any text in the forums. All errors have a red underline. Don't know about other browsers or OS though.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
"VOOM"?!? Mate, this bird wouldn't "voom" if you put four million volts through it! 'E's bleedin' demised!
Leon
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
If you assume the reader already knows what you are talking about, then you might get replies such as these - "gently" asking for more information.
Believe me, I've learned this from my own personal experience, so this isn't meant as a critique, but just a tip.
Now, as for the board, your specs should be easy to do. The question is how much power this will all take, and I'm guessing the final board(mosfets/interface circuit) could be done to consume ~10mA continuous current, maybe a couple mA less. That's just a rough estimate, but take it as a pretty good one.
The MOSFETs I have in mind may be overkill, but they are pretty cheap. I'm sure they can handle whatever you throw at them. They are rated for 55V, and 80A, but from my experience they can do 10A continuous with only a little heat. They also have built in Zener diodes, so the inductive kick from the solenoids won't be a problem.
Datasheet: http://pdf1.alldatasheet.com/datasheet-pdf/view/171111/STMICROELECTRONICS/STD60N55F3.html
As for the interface circuitry, I'm still looking but I've got a couple 16-bit shift register chips from TI in mind. If you want me to look into this and start a design, let me know. Remember, I'm looking for practice.
[noparse]:)[/noparse]
The original post wasn't meant create a storm bigger than Ben hur, It was supposed to invoke a few quick web links (as all my searches had turned up a blank) so as I could follow them and decide if any were suitable.
As far as the solenoids, they are designed to switch 6mm air hose line, so they aren't samll but I really don't know how big solenoids get. I would anticipate about 150 -> 250 mA hold in current each, but I have no definite figures on this.
And as they are in use on farms, should one fail they would be likely to be replaced with whatever the farmer has handy in their shed (that old solenoid salvaged from a tractor for example)..
And as far as spelling, I too use firefox and am familir with the wavey red line. But they don't appear in this forum (thus all my spelling must be perfect - no?). Perhaps their is something special I need to in order to get it working again in this forum?
I'd use solenoid valves, rather than the separate solenoids and valves which you seem to be using. They are much cheaper.
It's now three days and counting! I'd have had the whole thing designed, prototyped and working by now.
Leon
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
Post Edited (Leon) : 5/30/2009 10:35:46 AM GMT
Perhaps you have more disposable income than me, or perhaps you _always_ work alone? I have neither of those two luxuries.
My I suggest that if you are counting the days and could have done it better, then perhaps you should not bother with reading my forums posts anymore, as obviously you stand to gain no knowledge from my fumblings.
But, for the record, These units will be retrofitted to several existing installations and I have not been able to contact the relevant farmers to check exactly what they are using. Nor have I been able to speak to the field guy to see if any of the existing valves we are trialling have failed or if one particular brand has out-performed the others. Communications to some parts of Australia can provide difficult..
The last I heard the SMC valve block was working well, but that was over a week ago...
Can the current draw matter that much? Surely one 6mm solenoid valve draws about the same current as another (I'm sure there are specialist valves that draw different currents, gut not the bog standard types). Wouldn't any design be made to cope with {say} upto 2A draw per point?
Hence, my original post was just an ask for links to pre-canned boards (then I could work on the code - not on the 'interfaces'). I will concede that my original post wasn't particularly well phrased.
You were very unclear about what it was you were trying to do! It now seems that you are designing a controller and drivers that are going to be retrofitted to existing solenoid valves. What is the specification of those valves? You originally mentioned 150mA - 250 mA current, you now say it is up to 2A!
I very much doubt if you will find a COTS board with 10+ outputs that will do what you want, you will probably have to design it yourself or get someone to do the work for you. I'd simply use two 74HC595 chips (they are SPI-compatible with eight outputs each), MOSFET drivers and suitable 2A MOSFETs.
Leon
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
Post Edited (Leon) : 5/31/2009 5:18:33 AM GMT
As for your design, paclyne, I think I know what you are after. Like I said, if you want a board, I can whip a couple up for you - "pre-canned". The software should already be written. There are objects for "serial to parallel" chips, which I think I'll be using. This would be the objects used for this board - nothing more except the usual overhead code. The board would have 16 outputs, capable of well over 5A each.
Now, does that sound like what you are after?
(please, guys, no more bickering...)
On retrofitted solenoid valves it can be powered with =V and ~V that give You problems to drive it with MOSFET.
Only solution is to have driver PCB with micro relay's.
To drive that PCB You can use 74hc595 else I2C Expander's.
If You know that it is =V only and drive curent is no more that 500mA You can use ULN2803A Darlington drivers in place of micro relay's.
But it is not many that PCB's You can buy, You must produce them
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Nothing is impossible, there are only different degrees of difficulty.
For every stupid question there is at least one intelligent answer.
Don't guess - ask instead.
If you don't ask you won't know.
If your gonna construct something, make it·as simple as·possible yet as versatile as posible.
Sapieha
I now know where I can locally get a 8 point relay card (i2c) and will buy some of them. Means I'll have to pull a bit more current (keeping the relays energised, but I'll cope with that. That way I can provide more
We already have several working prototypes in the field (they are running on PLCs), but these are massive overkill {and cost} and have to have additional dedicated external equipment doing other stuff {RFID reading, load cell analysis, etc}. Hence the desire to move to a more embedded solution, then we can gradually phase out the other expensive bits, this is where the Prop shines.
The code I was talking about was moving the PLC code from ladder to spin, the plan was to utilise some of the excellent objects on the exchange for the 'clever' device driver code.
I will try and be more concise in my first postings, as I have tried to explain - I did not meant this to be bigger than Ben Hur.
BTW, how are "disposable income" or "working alone" relevant? I would have this prototyped and working in a couple of days - I'd get the parts the day after I'd ordered them. In the meantime I'd have designed a simple PCB and made it. An hour or so after the parts arrived the next day I'd have the board populated and be testing it.
Leon
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Amateur radio callsign: G1HSM
Suzuki SV1000S motorcycle
Post Edited (Leon) : 5/31/2009 9:43:55 AM GMT
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Timothy D. Swieter, E.I.
www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, 3.0" LCD Composite video display, eProto for SunSPOT
www.tdswieter.com
how'd it turn out? I jumped right to your site when I saw this *very* smart idea for a prop card. This has TONs of control applications!
What ampacity will the MOSFETs you plan to stock on it have?
> DMX/RS-485 ... encoder
Encode? I'm assuming the obvious - that the DMX will DEcode to control the I/O, right?
Do you have those routines canned into the Prop already? ... it wouln't be too difficult, if not.
Man, I would have broken down your doors to have one of these some years back for stage lighting and effects control (but that was WAY before even the Prop was around.)
cheers,
Howard
(PS Hope your move to Singapore went well --- I've made several overseas moves too --- including one where we thought our stuff went overboard into the Atlantic Ocean [noparse]:)[/noparse]
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
No matter how much you push the envelope, it'll still be stationery.
thanks for the link. Certainly looks like it has potential in my application ....
though I don't see the mosfet outputs, is that a separate board or am I missing the obvious?
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
=================
The future is in our hands.
Which way to the future?
=================
I think my words may have confused you Howard, let me try and rephrase what I said about the hardware.
There are three user interface LEDs - two are attached to I/O and one is attached to power. (note these two LEDs share the Tx/Rx line of the Prop Plug - we will see how this works in testing)
There is a user interface knob, which is an encoder, for doing any settings or adjustments (firmware is yet to be written that will dictate how the knob is to be used)
There are 24 MOSFET outputs. The MOSFETs are the ICs you see flanked on each side of the product with some heatsinking for the bottom of the IC. The MOSFET is an n-channel MOSFET with a rating of 30V and 7.5A, the data sheet is here: www.fairchildsemi.com/ds/FD/FDS6910.pdf
There is a RS-485 driver connected to the Propeller for receiving RS-485/DMX-512A. The lines for receiving data are not connected, though could probably be jumpered.
I want to create a full featured firmware, not just demo programs. The firmware will include DMX-512A receiving, controlling the MOSFET channels and setting address information. There may even be a stand alone cycling of the channels for testing or stand-alone operation.
I will probably start a new thread on this specific device once I get back to testing. I will try to bump this thread with a link.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Timothy D. Swieter, E.I.
www.brilldea.com - Prop Blade, LED Painter, RGB LEDs, 3.0" LCD Composite video display, eProto for SunSPOT
www.tdswieter.com
Have any estimates on how much the populated board will go for?
cheers,
- H
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
No matter how much you push the envelope, it'll still be stationery.