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. ------------------------------------------------------------------------- | Andrew B Smith | UUCP: andrew@kcl-cs.UUCP Dept. of Computing, | JANET: UDAC041@UK.AC.KCL.CC.VAXA King's College London, | BITNET, The Strand, | EARN: UDAC041%VAXA.CC.KCL.AC.UK@UKACRL.BITNET LONDON WC2R 2LS | United Kingdom | TPHONE: 01-836-5454 ext: 2239 | -------------------------------------------------------------------------
R_Tim_Coslet@cup.portal.com (07/10/88)
In article <188@lithium.kcl-cs.UUCP> andrew@kcl-cs.UUCP (Andrew B Smith) Writes: >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 Yes, I know it... It was called "Wiring Pencil" here when I bought it. > >This prototyping system has the advantage over wire-wrap in that the boards >are much thinner (the same as a PCB). And cheaper, as you don't have to buy wire wrap sockets that often cost more than alot of the parts (MSI TTL & CMOS ICs). > >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. I have used it alot (though never for very high speed stuff, so I don't know its performance above about 1MHz). My experience and recommendations are as follows. 1) The insulation can be difficult to burn off. So, Use a higher wattage Iron (>40W) to burn the insulation off quickly, a 25W Iron will take >10 seconds per pin and may thermally stress the ICs (In addition to producing intermitent connections). The last board I made with it I used a 100W soldering gun and had no bad joints. I also recommend using an Ohm Meter to check ALL connections on any board wired this way. 2) Be carefull with routing, don't let wires run randomly over other IC pins. The insulation can be stripped when you don't want to strip it, and cause shorts. 3) If you assemble with this system and solder directly to the IC pins (the cheapest way to do it) and find an IC is bad; don't try to unsolder it to replace it! The wires are VERY springy and will be almost impossible to keep in order. Just cut off the pins close to the package and solder the new part to the pins of the old one. Good Luck. I like the Wiring Pencil system. It is much quicker than doing a PC board and cheaper than wire wrap. But it does require a few different methods than other systems. R. Tim Coslet UseNet: R_Tim_Coslet@cup.portal.com BIX: r.tim_coslet
mohamed@cs.glasgow.ac.uk (Geoff Mohamed) (07/19/88)
In article <7222@cup.portal.com> R_Tim_Coslet@cup.portal.com writes: > > 1) The insulation can be difficult to burn off. So, Use a higher > wattage Iron (>40W) to burn the insulation off quickly, a 25W Iron > will take >10 seconds per pin and may thermally stress the ICs > (In addition to producing intermitent connections). The last board > I made with it I used a 100W soldering gun and had no bad joints. > I also recommend using an Ohm Meter to check ALL connections on > any board wired this way. Tim doesnt mention if his soldering irons are temperature controlled. If they are, then NO amount of wattage will burn the insulation if the tip temp. is too low. I actually bought a cheap (Antex) 15W iron for this use. It doesn't have any temp control so the tip gets very hot. A good soldered joint can be made in <5 seconds (typically 3 seconds). > 3) If you assemble with this system and solder directly to the IC > pins (the cheapest way to do it) and find an IC is bad; don't try > to unsolder it to replace it! The wires are VERY springy and will > be almost impossible to keep in order. Just cut off the pins close > to the package and solder the new part to the pins of the old one. Use sockets, they are less hassle all round. Cheap sockets protrude further so if you need to mod the board you can easily add another wrap on top of an existing one. Turned pin sockets have shorter legs so are trickier to use. You can have problems with the combs falling out. A friend suggested fixing this by applying a hot needle to the lugs from the component side of the board. This then forms a sort of rivet out of the plastic. Geoff
R_Tim_Coslet@cup.portal.com (07/22/88)
In article <1498@crete.cs.glasgow.ac.uk>: mohamed@cs.glasgow.ac.uk (Geoff Mohamed) Writes: >In article <7222@cup.portal.com> R_Tim_Coslet@cup.portal.com writes: >> >> 1) The insulation can be difficult to burn off. So, Use a higher >> wattage Iron (>40W) to burn the insulation off quickly, a 25W Iron >> will take >10 seconds per pin and may thermally stress the ICs >> (In addition to producing intermitent connections). The last board >> I made with it I used a 100W soldering gun and had no bad joints. >> I also recommend using an Ohm Meter to check ALL connections on >> any board wired this way. > >Tim doesnt mention if his soldering irons are temperature controlled. If >they are, then NO amount of wattage will burn the insulation if the tip temp. No they were standard uncontrolled soldering Irons. My 25 watt was useless with this system ( I had to redo atleast every third joint I did with it ) so I switched to using the 100/150 Watt Gun I had (only other "soldering iron" I had then) and as I said had no further problems (except with rapid tip corrosion) R. Tim Coslet
pete@tcom.stc.co.uk (Peter Kendell) (07/22/88)
In article <1498@crete.cs.glasgow.ac.uk> mohamed@cs.glasgow.ac.uk (Geoff Mohamed) writes: >In article <7222@cup.portal.com> R_Tim_Coslet@cup.portal.com writes: > >Use sockets, they are less hassle all round. Cheap sockets protrude further >so if you need to mod the board you can easily add another wrap on top of an >existing one. Turned pin sockets have shorter legs so are trickier to use. > I agree. The other problem with those posh turned-pin sockets is that the wire has no corners to grip as it it does with the cheapo sockets. This means: a: The wire tends to spring off before you can solder it. b: There's less chance of the corner of the pin cutting into the insulation and helping to ensure a better joint. >You can have problems with the combs falling out. A friend suggested >fixing this by applying a hot needle to the lugs from the component side >of the board. This then forms a sort of rivet out of the plastic. Good idea. In the past I have fixed the combs down with loops of wire passed over the comb and soldered to spare pads on the other side. This is very effective where the wiring run makes a 90 degree turn, e.g. at the end of a row of chips. I've found the Verowire method very reliable. Boards that I made 6+ years ago are still working fine. The worst feature is those *!#$@^ plastic wiring pens. If the wire slips out of the end it takes an age to rethread it. -- ---------------------------------------------------------------------------- | Peter Kendell <pete@tcom.stc.co.uk> | | ...{uunet!}mcvax!ukc!stc!pete | ----------------------------------------------------------------------------
henry@utzoo.uucp (Henry Spencer) (07/25/88)
In article <629@flada.tcom.stc.co.uk> pete@flada.UUCP (Peter Kendell) writes: >>... Turned pin sockets have shorter legs so are trickier to use. >> > I agree. The other problem with those posh turned-pin sockets is > that the wire has no corners to grip as it it does with the > cheapo sockets... Of course, the other side of this is that you aren't going to have any reliability problems with the sockets, which definitely is not the case with the el cheapo sockets. I've heard enough people curse cheap sockets that I am reluctant to use them on anything significant. -- MSDOS is not dead, it just | Henry Spencer at U of Toronto Zoology smells that way. | uunet!mnetor!utzoo!henry henry@zoo.toronto.edu