andrew@kcl-cs.UUCP (Andrew B Smith) (07/06/88)
Hi, I am looking into the use of the 'Vero Wire' prototyping system for the construction of a small micro board. For those of you who do not know what 'Vero Wire' is (it may have a different name in your country) I shall explain. Vero Wire is a wiring system for creating prototype circuit boards. It consists of a pen and 30 SWG wire (I think may be thinner). The wire is copper and insulated. The user takes the wire and wraps it round the leg of an IC/component/socket and takes the wire onto a plastic comb. The wire is then routed along a series of combbs to the other components to which connections are required. When the routing for a particular wire is done the wraped connections are soldered to break the insulation and make a joint. This prototyping system has the advantage over wire-wrap in that the boards are much thinner (the same as a PCB). I would like to hear from people who have had experience with this system and the problems they have encountered (reliability, and types of circuit it is suitable for). I am interested in the effects of noise and crosstalk on the wires, and the sorts of speed of micro you can build. If I get a positive response and development looks promising I shall post an account of my experiences. Thank you, Andrew Smith.
agn@unh.cs.cmu.edu (Andreas Nowatzyk) (07/08/88)
I used Vero-wire and a similar technology distributed by Siemens for a system with more than 1000 standart TTL chips (arround 1978!) running at 10 Mhz. No problem. However, using today's faster logics (F, AS,...) will cause problems. All wires run in rather crowded channels and cross-talk becomes a problem. Also, you have to have reasonably good solder skills. PWR and GND must be dealt with by other means. Also, this method is not as fast as wire-wraping, but way cheaper. -- Andreas -- -- Andreas Nowatzyk (DC5ZV) Carnegie-Mellon University Arpa-net: agn@unh.cs.cmu.edu Computer Science Department Usenet: ...!seismo!unh.cs.cmu.edu!agn
tgg@otter.hple.hp.com (Tom Gardner) (07/09/88)
In your description of the Vero Wire system you forgot to mention that it is necessary to solder the wire to IC pin. This is done by using the soldering iron to burn through the insulation. The system does work, but there are a few potential problems to be avoided: Firstly burning through the insulation generates iso-cyanates, so make sure there is adequare ventilation. Secondly, examine every solder joint carefully to make sure that the solder has flowed correctly. Thirdly, use IC sockets, for obvious reasons. Fourthly, don't over-tension the wires: if you do and the board flexes then Stockhausen would be proud of the musical twangs that occur. Have you considered SpeedWire? This has a similar low-profile but the connections are made by an IDC mechanism. This is faster to build, the components probably cost more, and probably has the same reliability. I believe VeroSpeed in Eastleigh Hants sell the product. I hope this helps.
markz@ssc.UUCP (Mark Zenier) (07/10/88)
In article <187@lithium.kcl-cs.UUCP>, andrew@kcl-cs.UUCP (Andrew B Smith) writes: > > Hi, > > I am looking into the use of the 'Vero Wire' prototyping system for the > construction of a small micro board. For those of you who do not know > what 'Vero Wire' is (it may have a different name in your country) I shall > explain. Vero Wire is a wiring system for creating prototype circuit > boards. It consists of a pen and 30 SWG wire (I think may be thinner). The > wire is copper and insulated. The user takes the wire and wraps it round the > leg of an IC/component/socket and takes the wire onto a plastic comb. The > wire is then routed along a series of combbs to the other components to > which connections are required. When the routing for a particular wire > is done the wraped connections are soldered to break the insulation and > make a joint. > > This prototyping system has the advantage over wire-wrap in that the boards > are much thinner (the same as a PCB). > > I would like to hear from people who have had experience with this system > and the problems they have encountered (reliability, and types of circuit > it is suitable for). I am interested in the effects of noise and crosstalk > on the wires, and the sorts of speed of micro you can build. An alternative to the solder-strippable insulation are the insulation displacement systems. They use the same method as the flat cable connection systems, use regular 30 ga. wire wrap wire and are fast. (about 5-10 times as fast full hand (cut the wire and hand strip it) wire wrap, or about twice as fast as Cut-Strip-Wrap automatic wire wrapping available from OK. These systems were available from 3M, Robinson-Nugent, and BICC-Vero in the USA. ScotchFlex Breadboarding System from 3M consists of strips of insulation displacment terminals in a break-apart strip, and socket tops. The IDC terminals are on the bottom of the perfboard with pins that project thru the board, and the socket top is an IC socket with female connections on both sides. Quick Connect from Robinson-Nugent is either individual stake in terminals or fully assembled prototype boards. Likewise the BICC-VERO. Anything you could do on a double sided board would probably work, but Schottky TTL is going to need better power and ground than you can get with busbar and Vector board. (I found this out the hard way). In the 3M and RN, the IDC terminal is a slot in a tab. In the BICC-Vero the IDC terminal is an extension of the socket barrel (like a machined DIP socket), and is a cylinder with 2 insulation dispacment slots on each side, (like an T&B Ansley Tulip IDC contact). The hand tooling for BICC-Vero is different. I don't know the availability of these systems now, the impression I get is that people aren't supposed to build prototypes anymore, just buy a million dollars worth of Mentor workstation and simulate it all. :=) Mark Zenier uunet!pilchuck!ssc!markz "Kinda scary. One guy said he had heard they were a bunch of wierdo gourmets from somewhere in Orange County, looking for new taste thrills."
henry@utzoo.uucp (Henry Spencer) (07/11/88)
If possible, before diving heavily into this system, test to see how well
the vaporizing insulation really works. When I experimented a few years
ago, I wasn't impressed: soldering heat didn't seem to remove the
insulation nearly as reliably and completely as I would have liked.
Personally, I concluded some time ago that there is no way I am ever again
going to build a substantial circuit by any hand-wiring method. It's too
#@#%$ much work (unless you can hire a flunky to do it), and too error-prone.
Now, I admit that since making that decision, I haven't tackled any large-
scale digital projects (in which the two-dimensional nature of PC boards
starts to make trouble); we'll see how it goes next time I try one of
those. The small-scale stuff I've done has not presented any problems
in PCB layout (although I may be biased because I find the problem of
routing a well-packed board to be a fascinating challenge, sort of like a
technological jigsaw puzzle, and I seem to be good at it).
--
Anyone who buys Wisconsin cheese is | Henry Spencer @ U of Toronto Zoology
a traitor to mankind. --Pournelle | {ihnp4,decvax,uunet!mnetor}!utzoo!henryrusty@cadnetix.COM (Rusty) (07/14/88)
In article <1329@ssc.UUCP> markz@ssc.UUCP (Mark Zenier) writes: >I don't know the availability of these systems now, the impression I get is >that people aren't supposed to build prototypes anymore, just buy a >million dollars worth of Mentor workstation and simulate it all. :=) > > >Mark Zenier uunet!pilchuck!ssc!markz (No, No, not Mentor! Cadnetix!) :-) (see 'Organization' above) well, Having used the 3M version for some prototypes before I came to Cadnetix, I will share my personal experience: If you build a prototype with such a system, test it immediately, and then toss it aside, the prototype systems are pretty slick. HOWEVER, the wires are VERY sensitive to stress. Like, removing the IC more than once or twice; flexing the board, touching the wires too often, etc. can give you the best intermittents you have ever seen. Wirewrap lasts 'forever', almost. So think about how long you want the prototype to work and how much stress it will be under. ----- Rusty Carruth \ Cadnetix \ 5775 Flatiron Pkwy. \ Boulder CO 80301 \ (303) 444-8075 'HOME': P.O. Box 461 \ Lafayette, CO 80026 RADIO: N7IKQ UUCP:cadnetix!rusty DOMAIN:rusty@cadnetix.com PATH?:{uunet,boulder}!cadnetix!rusty
markz@ssc.UUCP (Mark Zenier) (07/16/88)
In article <3281@cadnetix.COM>, rusty@cadnetix.COM (Rusty) writes: ... > > well, Having used the 3M version for some prototypes before I came > to Cadnetix, I will share my personal experience: > > If you build a prototype with such a system, test it immediately, > and then toss it aside, the prototype systems are pretty slick. > > HOWEVER, the wires are VERY sensitive to stress. Like, removing the IC > more than once or twice; flexing the board, touching the wires too often, > etc. can give you the best intermittents you have ever seen. > > Wirewrap lasts 'forever', almost. So think about how long you want the > prototype to work and how much stress it will be under. I use a homemade breadboard using Vector board strengthened with aluminum extrusions and my prototypes are good for a couple of months of messing around. The setup has standoffs to keep the wiring off the tabletop. Problems I have found with Scotchflex. 1. When they say only two wires to a IDC connection (equivalent to 4 wirewrap), they mean it. The bottom wire will be cut in half if you try to tack on a third. 2. Flexing the wire from side to side relative to the the IDC slot will cause breaks since the wire is already creased. 3. If the board is too thick, the socket tops won't stay on. The combination of vector board and Wrap ID's is too thick. 4. I break about 10% of the IDC terminals each time, no big deal (except for schools) since they are only good for 25 times (3M says). 5. It's expensive, 500% over cheap wirewrap. Since 3M has bought AP , one of the major sellers of socket breadboards, I would expect Scotchflex to remain in the background, which is a pity given the advantages of speed and low profile. Mark Zenier uunet!pilchuck!ssc!markz "Kinda scary. One guy said he had heard they were a bunch of wierdo gourmets from somewhere in Orange County, looking for new taste thrills."
sdp@littlei.UUCP (sdp) (07/19/88)
In article <3281@cadnetix.COM> rusty@cadnetix.COM (Rusty) writes: >If you build a prototype with such a system, test it immediately, >and then toss it aside, the prototype systems are pretty slick. > >HOWEVER, the wires are VERY sensitive to stress. Like, removing the IC >more than once or twice; flexing the board, touching the wires too often, >etc. can give you the best intermittents you have ever seen. We are talking about the 3M prototyping system where wires are pressed into narrow grooves in the pins on the back of the board, right? My experience with this was much the same as Rusty's. I had to build a ROM emulator sort of thing to use as a tool, not a prototype. Being a software guy, and having had bad luck with wire-wrap before, I thought this 3M stuff would be great. Through the assembly and debugging stage, it was much more convenient than wire wrap. After a week or two, things started getting flakey. I thought about soldering all the wires in place after the thing was debugged, but the sockets and other plastic parts seemed to melt easily. Next time I'll do it right. I'll get a hardware tech to do it for me. Scott Peterson OMSO Software Engineering Intel, Hillsboro OR sdp@sdp.hf.intel.com uunet!littlei!foobar!sdp!sdp