Moving to a permanent board
dtalvacchio
Posts: 36
Hello-- I'm a newbie who has gotten quite a lot of good advice on this forum, hoping for a little more . . .
I have a working prototype for a digital clock which features six large (1-inch) 7-segment display digits and which uses the Basic Stamp in combination with a crystal, a counter, and the Maxim digit display driver. I'm ready to move it to a permanent board (and then mount it in some sort of enclosure), and I'm really not sure where to start . . . One suggestion I received was to have a custom PCB made for the 6-digit display (as well as for time-setting buttons and LEDs for colons) and then to use a Super Carrier Board for the rest of the circuit, including the ICs, etc. This sounds fine, but I would then have two questions:
(1) How would I connect the PCB components to the Super Carrier components? Seems like I would have to allow for such a connection in the PCB design, but I have no idea what kind of connection this would be.
(2) On the Super Carrier Board part, do I have to wire-wrap the components? Is any soldering involved in this process?
I also have a Homework Board, but I'm guessing that I can't use its built-in breadboard in a permanent design, right?
If someone could give me specific guidelines just to get me started, I'd be very thankful . . .
I have a working prototype for a digital clock which features six large (1-inch) 7-segment display digits and which uses the Basic Stamp in combination with a crystal, a counter, and the Maxim digit display driver. I'm ready to move it to a permanent board (and then mount it in some sort of enclosure), and I'm really not sure where to start . . . One suggestion I received was to have a custom PCB made for the 6-digit display (as well as for time-setting buttons and LEDs for colons) and then to use a Super Carrier Board for the rest of the circuit, including the ICs, etc. This sounds fine, but I would then have two questions:
(1) How would I connect the PCB components to the Super Carrier components? Seems like I would have to allow for such a connection in the PCB design, but I have no idea what kind of connection this would be.
(2) On the Super Carrier Board part, do I have to wire-wrap the components? Is any soldering involved in this process?
I also have a Homework Board, but I'm guessing that I can't use its built-in breadboard in a permanent design, right?
If someone could give me specific guidelines just to get me started, I'd be very thankful . . .
Comments
I don't know what you're using at present.· A BoE or a HWB?· Maybe you should just put·all of that·in an enclosure, as is, and save some money.
Yes, soldering would, inevitably be involved in the process, otherwise.·
Having a printed-circuit board made up seems... extravagant.· At RadioShack you can buy an experimenter board which has the same patterns as a solderless breadboard.
Interfacing with a super-carrier would involve bringing over the wires necessary for your clock board's operation, sort of like you are already (??).· The super-carrier has all of the I/O pins available.· You could use connectors between the two boards, too, if you can manage.
[noparse][[/noparse] Wire-wrap?· Wow, it's 1982 all over again. ]··
My (gentle) suggestion is that you might consider putting the whole shooting match as you have it now, in an enclosure.· The HWB has holes for stand-offs and your clock breadboard probably (??) does, too.·· You could drill your box for the buttons and run the wires to your clock breadboard. ·This way, you're fancied-up some, but you can change your mind later (you have options.)
I wouldn't mind using the homework board and a small breadboard, as long as I could be sure that the connections would be safe and reliable. Do you think they would be?
"safe and reliable" -- maybe you couldn't ship it cross country and expect everything to be just right, but given ordinary care I suppose it should be OK.· Like, if everything were placed onto a board and you shake it about and it's none the worse for it... then Bob's your uncle.· As you say, it's art, for exhibit, others may not·accord it the care you would; those are practical considerations, too.
This has been posted on a lot: you could hot-melt-glue everything in place.· (Evidently, once it sets up, hot-melt can be peeled up still, it's "semi-permanent.")
If you're making money on it, then maybe you should spend money on it.
What to do...
[noparse]/noparse][color=white]·[/color]I've made lots of projects, at home and on-the-job, but never had a pc-board made for a one-off, that's what prototyping is all about.[color=white]·[/color] And I don't have a hot-melt-glue gun.[color=white]·[/color
Post Edited (PJ Allen) : 7/2/2006 3:47:42 AM GMT
Copper clad board
UV lamp
software
some papers
a clear film photosensitive
photo resist
screws
drill
cutting board
safelight
developing chemicals
developing tray
The softwares are $600-$10,000. This is all I know.
www.expresspcb.com/
www.cadsoft.de/
www.freepcb.com/
www.batchpcb.com/index.php
Our recommendations will only be as good or as appropriate as the information that we have. If you could provide us a picture of what you have now, it would give all of us more information with which we may be able to offer better suggestions. As they say "A picture is worth a 1000 words" and as a visual artist, I'm sure you're well aware of that concept.
Even before you offer such a picture, let me just say this. Some folks seem to be a bit reluctant to "show and tell" due to the fact that it's their very first project. In that vein, remember one thing - we ALL had a "first project" and it may WELL have looked far worse than yours and/or far worse than any other of the "first project" that have been presented here.
In the almost 10 years I've been on this forum, the ONLY "complaints" I've ever heard from the "peanut gallery" are when the wiring looks like a rat's nest, or when a novice has used all one color of wire for every circuit. In either/both cases, this is: 1) part of the learning process, 2) something that can be rectified, and 3) something that can make your life easier when it's rectified. With that said, please give us a peek at it.
Just based on what you've said so far, I'm not sure that a plain old BS-2 carrier board is out of the question, but that may depend on your current (amperage) needs. As I remember, they are only $20.00 US apiece.
Regards,
Bruce Bates
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·· We have had some conversation on this subject before regarding the following project (linked).· In my case my original plan to recommend to people building it would have been to mount the displays on a PCB (custom).· However, barring that you could still point-to-point on a solder ring board.· This would involve soldering.· Wires could go down to the Super Carrier Board (yes, I was going to use that too).· The Supoer Carrier Board would hold all of the chips in your case since you don't have the shift registers.· In my case I was going to move all the display parts to a PCB for that and only have the DS1302 and DS1620 on the Super Carrier Board.· Having a schematic (or at least a wiring diagram/sketch) will help you see the necessary connections.· I hope this helps some.
http://forums.parallax.com/showthread.php?p=552892
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Chris Savage
Parallax Tech Support
csavage@parallax.com
I've seen that when wire-wrapping the ICs go into sockets with the proper number of pins, but what I don't understand yet is what to do with things like the seven-segment displays, or the resistors and capacitors. Are these also inserted into some sort of socket? Could someone maybe send me a link to the kind of item I would need?
You will need sockets, wire wrap wire (30 ga.), perfboard (plain), and a wire wrap tool (with stripper).· You can get all this at Jameco.· As far as I've seen, Jameco only sells the 'manual' type of wrap tool, which is OK for small jobs such as what you are planning.
To mount descrete components and 7-seg displays, you can use the IC sockets (e.g. a 16 pin·IC socket can hold 8 resistors, etc.).· Some components·can be directly wirewrapped·if the lead is rugged enough and similar in size to the leg of a socket (LED lead - yes, IC pin - no).· The socket legs are machined square, and this is important for a good connection.· If I wirewrap the lead of a component that is not exactly like a socket leg, I usually put a touch of solder on it after wrappping it.
The only·disapointment of wirewrapping to me·is the cost of the sockets, but nothing in life is free.· If you take into account the speed of producing a small wirewrapped board, vs the time, effort and $ for a custom PCB, I still think wirewrapping is viable.
Nate
Post Edited (Nate) : 7/3/2006 7:53:55 PM GMT
Since my seven-segment LEDs are fairly large (1-inch high), I can't imagine that I would find an IC socket wide enough to accomodate both the top and bottom rows of pins on the digits. Does this mean that I would use two IC sockets, one along the top and one along the bottom, for each seven-segment display? Or do they make "rows" of sockets?
Also, I'm confused by something on the Carrier Board. (I figure I should put some components on the Carrier Board and the rest on the perf board.) It looks like the Stamp's I/O pins connect to square wire-wrapping legs which are on the top of the board. Shouldn't all the components be placed on top, and all the wire-wrapping would happen on the bottom side? Do I wire-wrap to these pegs on top and send wires through the holes toward the bottom, where I make connections to the other components?
·· On the displays you use SIP Wire-wrap sockets...On on the top, and one on the bottom (or sides, as the case may be).· Then you can position them as far apart as needed.· One piece of advice...When I started wire-wrapping (like 20 years ago) I kept having problems thinking backwards...See, in wire-wrapping you work from the bottom side of the board, so the pins appear flipped on that side.· There used to be a neat product out called "Wrap-ID", which I think is still available and I loved using them because it showed the pin numbers on the bottom side of the board in the correct order.· Made my life a lot easier.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Any thoughts on the Carrier Board question?
·· Sorry, the Super Carrier Board is irrelevent if you're going to wire-wrap everything.· I'm not sure it would be a good idea to use that board in that case because it's not designed for it (Soldering required).· As for putting more than two wires on a wire-wrap post, where did you hear that?· That is incorrect.· If you couldn't do that wire-wrapping would be useless because you could never create a complete circuit.· As an example, I wire-wrapped entire Z80 control boards...Take a look at the attached pictures of one of my Z80 controllers...They don't show the bottom side, unfortunately (these are old pictures that were scanned), but you can see the number of chips, and believe me, there are many connections with 2 or more wraps.· If you have a good wire-wrap tool (i got mine at Radio Shack), it can handle 2 wraps easily.· With good planning that's all you'll need.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
2) Never used or possesed a Carrier Board, but if I look at this: http://www.parallax.com/detail.asp?product_id=27130·it looks like it has the Stamp pins brought out 3 different ways on the Carrier Board:
One on the prototyping area (to right of Stamp socket) - you could solder a connection wire to these through-holes for a connection,
Another to a 22 ga. wire connector (below Stamp socket) - you can simply push·stripped 22 ga wire in the appropriate hole to make a quick but not permanant connection,
Another to a connector to the left of the Stamp - these connectors are similar to the connectors on the top of the wirewrap sockets you will using, appropriately sized wire or IC pins will make a connection if pushed into these brass holes (I find that 22 ga. wire is too big for these, but the wire lead of a 1/8W resistor or a typical cap works well).· I do not see any wirewrapping posts on this board.
Not that I want to talk you out of Parallax products, but I don't really see why you would use the Carrier Board in addition to a board to hold the 7-Segs - if you're building the 7-seg board, just mimic the carrier board components/connections·on the perfboard in addition to your display circuit and you're done.· If you still have the desire to spend money on Parallax products, buy a new BS2 for future designs.
Nate
EDIT - You can buy wirewrap sockets with different length legs, made for·wrapping 1 to 3 wraps on them.· Buy the 3 wrap length ones, you will never regret having extra room.· Some people say that you should cut off the unused portions after wrapping to cut down on stray capacitance - I say if you are building a circuit that is that sensitive to stray capacitance (RF circuits), you probably should be using a custom PCB.· (Your circuit as shown will not have this problem)
Post Edited (Nate) : 7/3/2006 8:50:32 PM GMT
www.parallax.com/detail.asp?product_id=27120,
not the Super Carrier Board. Are those square wire-wrap posts?
You ask a good question about the Carrier Board. I thought it would make things simpler, as I'm not sure how to set up power and ground connections, and it already has those built in. I also wouldn't know how to get the program to the Basic Stamp without one of these boards . . .
Is setting up the power and ground connections easier than I'm assuming?
Look at the schematic for your posted board here http://www.parallax.com/dl/docs/prod/boards/BS2CarrierBdSchem.pdf· - ·If you program your Stamp on your homework board then transfer it to the perfboard, I believe all you need to copy are the ground, power and reset connections.
Others please·feel free to correct me if I'm wrong, it's been awhile since I've used a BS2 (Only use SX now).
Nate
Post Edited (Nate) : 7/3/2006 8:52:13 PM GMT
·· I thought you had the Super Carrier Board...The one you have you could easily wire-wrap to the posts along the sides of the BASIC Stamp socket.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
·· Look 4 posts up...Carrier Board...
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Chris Savage
Parallax Tech Support
csavage@parallax.com
And then I can wire-wrap using the surrounding thru-hole prototype space, by running sockets through the holes? Sorry for needing so much clarification . . . I just don't want to order a bunch of stuff and learn the hard way that I can't use it.
·· Yes, that should work just fine.
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Chris Savage
Parallax Tech Support
csavage@parallax.com
Just two more questions, and then I think I'm on my way . . .
1. I just read somewhere that discrete components like resistors must be soldered to a "header" which then goes into the IC socket. Is this always true, or can one sometimes get away with just inserting the component's leads into the socket?
2. I have to make 6 ground connections, and I read somewhere that it is possible to use a bus strip to short together a row of a socket, so that there is a common ground where I can make all 6 connections . . . but I haven't been able to find these bus strips at Jameco or anywhere else. Can someone point me in the right direction? Or is there a better way to make a shorted-together strip? (I'll need such strips for two other parts of the circuit as well.)
Best,
Dominick
·· The problem with just inserting the discrete components is that the wire-wrapping won't work on them, since the leads are round.· Wire-wrapping depends on the fact that the wire-wrap parts have square leads, which helps the wire hold on when it's wrapped.· Just use a wire-wrap socket and insert the leads across opposite sides of the socket.· You'll notice in the first picture I posted earlier up the thread I did stick some .1uF caps in without the sockets...I ended up tacking them with some solder, which you shouldn't do.· In the second picture (which was actually the first board I built like that) I had 4 resistors in a socket.
·· As for the bus strips...That term is too common to know exactly what part you mean, but you can just tie those points together using wire-wrap wire...Remember, you can wrap more than one wire per post.· I hope this helps.· Take care.
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Chris Savage
Parallax Tech Support
csavage@parallax.com