Using jumpers to quickly swap components - Page 1
Forum section: electronics / projects

author: HendriXML
author_rank: Super Contributor
timestamp: February 20, 2019, 01:50:15 pm
content: Hi,Did a quick experiment on how to use jumpers to make resistors (or other components) swappable, to enhance the joy and speed of experimenting on a perfboard.It needs a bit more spacing because of the 2x2 headers.But compared against using crimped/soldered dupont connectors they are handier.Using the test perfboard you get a "third hand"No need to crimpGood orientationSpacing is accurateEasy to have different spacingsEasy to swapShorter “legs”More isolatedI measured the voltage drop of (2) it was 17.9 mV at 3.2A making a resistance of 5.6 mOhm.The used wire in between dropped 0.9mV so it had a resistance of 0.3 mOhm.Thus the jumper connections are about 5.3 mOhm.Good enough for a lot of applications!While soldering some care has to be taken not to solder to the header.

author: magic
author_rank: Super Contributor
timestamp: February 20, 2019, 02:27:10 pm
content: Pro tip: check out SIL/SIP sockets.

author: HendriXML
author_rank: Super Contributor
timestamp: February 20, 2019, 02:34:12 pm
content: They’re on order. Had previously only bought one strip. That one I used as a tiny breadboard. Handy stuff.Maybe I will do a comparision, but I don’t think the tick wire will fit

author: Ian.M
author_rank: Super Contributor
timestamp: February 20, 2019, 02:43:13 pm
content: You can also cut up turned pin IC sockets if you don't have any SIL turned pin socket strips handy. For components with a similar lead diameter to the turned pin pin, if the lead is cut cleanly it will plug straight in. If there is a moderate diameter mismatch, solder the lead into the socket side of another turned pin socket and use the pin side as a plug.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 20, 2019, 07:33:46 pm
content: IC sockets may be a bit too tight, in which case the next best (top best??) option would be Mill-Max headers/sockets, available in all sorts of sizes. Pricey as frig though.Plain rectangular spring contacts would be fine (how solderless breadboards do it), but they don't seem to be as available, with contacts sprung for small minimum diameter leads. Regular 0.025" square pin header sockets are pretty wide open, not good for much besides square pins.I've done it that way too, with a socket header in the board and components soldered to pin headers. Not as freely pluggable as random proto-bin components (need to prepare a component+header assembly), but alright when you have just a few combinations to try.Tim

author: NorthGuy
author_rank: Super Contributor
timestamp: February 20, 2019, 07:43:50 pm
content: Looks like you're re-inventing solderless breadboards

author: HendriXML
author_rank: Super Contributor
timestamp: February 20, 2019, 07:50:12 pm
content: But with the benifits of inhaling solder fumes

author: Audioguru
author_rank: Super Contributor
timestamp: February 20, 2019, 08:49:46 pm
content: Wait a minute! Why do you need to swap components?Because you neverlearnedhow to simplycalculatetheir values and you are using "trial and error" instead?I never guess about component values, I calculate the values byreading the datasheetminimum and maximum spec's for an active device the components are used with. Then my circuits work perfectly without changing anything.Oh yeah. I buy quality parts, not junk from "over there".

author: HendriXML
author_rank: Super Contributor
timestamp: February 20, 2019, 08:58:59 pm
content: That’s cool. The way I “calculate” my fuses for instance is that I start with the lowest value one and then climbing up until the new one doesn’t blow any more.

author: Audioguru
author_rank: Super Contributor
timestamp: February 20, 2019, 09:19:44 pm
content: Quote from: HendriXML on February 20, 2019, 08:58:59 pmI hope you don't do the same with car tires and other car parts.

author: HendriXML
author_rank: Super Contributor
timestamp: February 20, 2019, 09:31:56 pm
content: Quote from: Audioguru on February 20, 2019, 09:19:44 pmLots of calculations, but gladly also a lot of testing is done when designing car tires. It’s hard to fully model the real world, you must agree on that. Experimenting and checking is as a method simply irreplaceable.

author: james_s
author_rank: Super Contributor
timestamp: February 20, 2019, 09:58:51 pm
content: Quote from: Audioguru on February 20, 2019, 08:49:46 pmI calculate to get a reasonable starting point but I often find that I need to tweak things a little in the real world to get some things working properly. Other times I'll be doing more of a seat of the pants thing and just experiment to see the effect of a particular component on the circuit. Being a very visual thinker I find that a lot more interesting than plugging numbers into an equation. Not everybody playing with electronics is a professional engineer and there's no reason to look down on them for that. You have a process that works for you, he has a process that works for him, so what?I mean did you come here to help, or just to show off how smart you are?

author: KL27x
author_rank: Super Contributor
timestamp: February 21, 2019, 12:37:50 am
content: I spent a couple years making "useful stuff" like this. I think it's just a phase some of us go through.Prediction. In 2 years, you will be using mostly smd parts and swapping them out with a hot air station.

author: HendriXML
author_rank: Super Contributor
timestamp: February 21, 2019, 12:52:26 am
content: Quote from: KL27x on February 21, 2019, 12:37:50 amJust curious, but how does one prototype with smd parts without using designed pcb’s?

author: Fire Doger
author_rank: Regular Contributor
timestamp: February 21, 2019, 01:27:09 am
content: Quote from: HendriXML on February 21, 2019, 12:52:26 amThey don't, they design PCBs *(Unless you mean prototyping something basic that can be calculated on the back of an envelope)The question is what kind of pcbsFor simple layoutsThey break it into small schematics according to functionality and build them individually for faster workflow, debugging etc...If its simple (no tiny tracks, BGA etc) then probably you can do it on a diy pcb. If you got a set up for home pcds it will be very fast.It takes me 1h to print it while doing something else at the same time.For complex layouts (BGA - Multylayer)You rely on datasheet, examples, appnotes, etc. Good EDA helps too.Many times "calculating" may be much more expensive than building it.Everyone at the end have to build it as final product. PCB is part of the circuit and interacts with it. (you can see it clearly when speed-voltage-current-temperature goes up)Ending with many prototype pcbs is not unusual... The key is to minimise the number/cost of them.

author: HendriXML
author_rank: Super Contributor
timestamp: February 21, 2019, 02:15:37 am
content: Quote from: Fire Doger on February 21, 2019, 01:27:09 amThanks. Making my own PCB’s is not on my list yet, and to have them manufactured takes a while. So in the mean time I’ll be having fun with THT and perfboards. For me it is a hobby, where I find the part of soldering fun as well. Desoldering not so much, hence the topic.

author: james_s
author_rank: Super Contributor
timestamp: February 21, 2019, 02:47:44 am
content: I've been prototyping lately on blank copperclad, sort of like the old "deadbug" technique. I could never get past the ugly mess it looks like previously but I've managed to develop a fairly tidy technique and it sure performs well for high frequency stuff. Things like SMPS ICs and mosfet drivers that I previously had a lot of trouble getting to work correctly are no problem this way. Big continuous ground plane works even better than a regular PCB in many cases.

author: Audioguru
author_rank: Super Contributor
timestamp: February 21, 2019, 03:31:13 am
content: Quote from: james_s on February 20, 2019, 09:58:51 pmMy help is for you to read the spec's in the datasheets then calculate what is needed to meet them. Also to buy quality components.A model was mentioned, for a simulation? Most simulations simply use "typical" active parts, ignoring minimum and maximum spec's so some of the assembled circuits will not work. You can either throw away the ones that don't work or fiddle with them if all the spec's were ignored.

author: Siwastaja
author_rank: Super Contributor
timestamp: February 21, 2019, 09:25:50 am
content: Quote from: HendriXML on February 21, 2019, 12:52:26 amEasily.- 0402, 0603 and 0805 passives fit between two pads on standard through-hole breadboards, if you want to use those. SOT-23 and similar also fit just fine,- For many circuits, use bare copper clad FR4 as a full ground plane. Dead-bug ICs (turn them around), bend the ground pins and solder them down. For power decoupling, you can solder another end of a 0603 cap to the ground copper, another end to the pin directly. For the rest, solder in air wires. Fairly easy to solder a 0603 resistor directly to a pin, leave another end hanging in air, later solder a wire to this pin.Not much slower than working with through hole parts.

author: HendriXML
author_rank: Super Contributor
timestamp: February 21, 2019, 10:38:10 am
content: Quote from: Siwastaja on February 21, 2019, 09:25:50 amWith KiCad (which I use) it is possible to flip the board, thus it should stil be possible to have some visual guidance. I’m using that already to create “traces”. Using a perfboard it should also be possible to mix THT and the dead bugs. Dead bugs are then soldered on the bottom side. The “step up” to SMD for me will probably go slowly, so I like this possibility! I know that there’re also adapter boards for SMD, but those aren’t that cheap and you need to have them at stock.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: February 21, 2019, 12:21:25 pm
content: Quote from: HendriXML on February 21, 2019, 12:52:26 amWith a utility knife:Note I tend to mix "Manhattan style" construction (PCB chits making elevated tie points) and THT components (which can be wired pretty much anywhere, they're free jumpers).Tim

author: netdudeuk
author_rank: Frequent Contributor
timestamp: February 21, 2019, 12:45:43 pm
content: You can use the OP's proto board for SMD prototypinghttp://elm-chan.org/docs/wire/wiring_e.html

author: Buriedcode
author_rank: Super Contributor
timestamp: February 21, 2019, 03:00:40 pm
content: Just wanted to add, SMD parts work nicely with stripboard too. 1206 is usually needed to span tracks broken with a drill bit (broken at a hole) but 0603 or 0805 are fine for connecting adjacent tracks. Because SMD passives tend to be very cheap (except maybe higher value caps) I use them as often as possible.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: February 21, 2019, 03:27:08 pm
content: The passive components in the photo that I included above are 0805s. The holes in the board are 0.1" pitch so they fit how the same components would appear on stripboard.

author: HendriXML
author_rank: Super Contributor
timestamp: February 21, 2019, 09:34:47 pm
content: Thanks for all the reactions, it really shows there’s not one “right” way to do stuff!

author: Buriedcode
author_rank: Super Contributor
timestamp: February 21, 2019, 10:29:26 pm
content: Quote from: netdudeuk on February 21, 2019, 03:27:08 pmI meant, with stripboard one tends to cut tracks over holes, with a drill bit, meaning the gap can be >3mm between copper, which can be too much for an 0805. But I tend to cut tracks between holes anyway, so it doesn't matter.

author: james_s
author_rank: Super Contributor
timestamp: February 22, 2019, 12:09:45 am
content: I also prototype with SMT parts on perforated prototype boards. Originally I was inspired by Elm Chan, (Google if you haven't seen his projects) I can't match his neatness but I can make stuff that works.When I prototype on blank copperclad I sometimes put polyamide tape down under pins I don't want to connect to the ground plane. For DIPs I bend the thin part of the legs I want to connect outward and solder the ground pins butted up to the board. I don't like to flip the chips upside down, I have too much trouble keeping track of what is what and which pin is which.

author: HendriXML
author_rank: Super Contributor
timestamp: February 22, 2019, 12:29:44 am
content: Quote from: james_s on February 22, 2019, 12:09:45 amIt is surely amazing.

author: Siwastaja
author_rank: Super Contributor
timestamp: February 22, 2019, 07:11:22 am
content: I think the best way isnotto overthink it. You'll find the best method of ad-hoc prototyping by just doingwhatever needs to be done, in that moment, when you need it, without thinking too much about whether this is "the right way". After all, lab prototyping is all about one-offs, andyourworkflow, so do it the way which is quickest to you. These prototypes often don't need to be robust.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: February 22, 2019, 08:07:01 am
content: Quote from: Siwastaja on February 22, 2019, 07:11:22 amI linked the Elm Chan on the previous page, as an example of what can be achieved.However, I agree with the overthinking and his work seems like the returns may not be so rich.I overthink myself and it definitely slows me down and even stops me completely. Have a look at Mike's LCD hack to see an example of what can be achieved when you don't mind what the rig looks like

author: tggzzz
author_rank: Super Contributor
timestamp: February 22, 2019, 09:15:55 am
content: Quote from: HendriXML on February 21, 2019, 12:52:26 amBreakout boards.SMD friendly prototyping boards.http://www.busboard.com/surfacemountpcbshttps://github.com/electroniceel/protoboardhttp://www.talkingelectronics.com/EM/Matrix%20Boards/MatrixBoards.htmlManhattan techniques, especially for decoupling in RF circuits.All those are better than solderless breadboards, but thenanythingis better than solderless breadboards.

author: Zero999
author_rank: Super Contributor
timestamp: February 22, 2019, 10:55:09 am
content: Quote from: Audioguru on February 21, 2019, 03:31:13 amYes some SPICE models are poor, especially at simulating the output stage of op-amps. I've had problems with the TL072 model showing it sinking current when the output is saturated to the positive rail and I remember someone saying they simulated an LM358 circuit and the model suggested it can sink 10mA, with the output at only 100mV, with respect to the op-amp's negative supply.Datasheets are generally better than SPICE models but are still often imperfect, so it makes sense to prototype.

author: Nusa
author_rank: Super Contributor
timestamp: February 22, 2019, 11:45:55 am
content: I've been known to put components on protoboards (dead-bug style if they don't go directly) to create breakouts to header pins. Then I can use the square header pins as wire-wrap posts to connect things up. I've got some long headers for cases where I expect to need several wraps.I'm also fine soldering mod wires when that's appropriate, but no reason to throw out techniques learned 45 years ago, and tools I already own, that still work.

author: netdudeuk
author_rank: Frequent Contributor
timestamp: February 22, 2019, 12:15:48 pm
content: Quote from: Nusa on February 22, 2019, 11:45:55 amI've done something similar.