Building a home lab for educational purposes - Page 1
Forum section: electronics / beginners

author: bifferos
author_rank: Regular Contributor
timestamp: June 06, 2021, 03:24:02 pm
content: Has anyone knocked up their own basic circuit components with 4mm banana plug terminal posts for connections? I can't find anything like this now but we had stuff like this at school >30 years ago. I found an ammeter:https://www.lymart.com/wholesale-price-dc-milliammeter-0-6a-3a-analog-dc-current-meter-ammeter-for-student-lianying-product/But I'd also like batteries, capacitors, resistors, transistors, inductors. Basically a box with 2-3 terminals, space inside for the component and a top panel where I can put the symbol showing what's inside. Of course there are many ways to make this from scratch, I'm just looking for any shortcuts or advice.thanks!

author: RoGeorge
author_rank: Super Contributor
timestamp: June 06, 2021, 03:45:59 pm
content: That type of wiring is not very common any more.Nowadays instead of 4 mm bananas people are using$1 digital multimeters (DMM)with wires and parts plugged into universal breadboards like this very small one (pic fromhttps://en.wikipedia.org/wiki/Breadboard):

author: bifferos
author_rank: Regular Contributor
timestamp: June 06, 2021, 04:01:37 pm
content: Indeed. I wasn't really sure if this kind of thing is suitable for 7 yrs old, but it would make things significantly cheaper!

author: rstofer
author_rank: Super Contributor
timestamp: June 06, 2021, 04:07:48 pm
content: There are many 'snap together' electronics kits with a book of experiments like:https://www.amazon.com/Snap-Circuits-SC-300-Electronics-Exploration/dp/B0000683A4While breadboarding CAN be done by young people, I would think the snap together experiments would be more entertaining.

author: RoGeorge
author_rank: Super Contributor
timestamp: June 06, 2021, 04:08:44 pm
content: Some are made with transparent plastic, much better for learning because the internal connections of the breadboard are visible, e.g.:https://www.ev3dm.com/product/transparent-breadboard-83-x-55-mm/

author: bifferos
author_rank: Regular Contributor
timestamp: June 06, 2021, 04:20:56 pm
content: Quote from: rstofer on June 06, 2021, 04:07:48 pmI've been put off by these because I can't see myself re-using any of the bits. I guess the flip side is you get a book with it and it's more structured than anything I'd come up with.

author: rstofer
author_rank: Super Contributor
timestamp: June 06, 2021, 04:52:33 pm
content: Well, you did mention a 7 year old. To me, that's a very different scenario than a lab for an adult. I guess it doesn't have to be but I would think a 7 year old is going to want to see something happen.

author: themadhippy
author_rank: Super Contributor
timestamp: June 06, 2021, 05:03:39 pm
content: QuoteThe stuff we had school used plastic trunking. The lid was screwed to a wooden board ,think there was 4 or 5 strips of lid on each board and you just pushed the individual component blocks on to it.The components were inside the trunking with 4mm sockets and the relevant symbol on what would normally be the bottom of the trunking.

author: ledtester
author_rank: Super Contributor
timestamp: June 06, 2021, 05:09:27 pm
content: > Basically a box with 2-3 terminals, space inside for the component and a top panel where I can put the symbol showing what's inside. Of course there are many ways to make this from scratch, I'm just looking for any shortcuts or advice.There are a lot of plastic enclosures you can get to house electronics. Here's what Farnell UK has to offer:https://uk.farnell.com/w/c/enclosures-racks-cabinets/enclosures-boxes-cases/plastic-enclosures?ost=enclosureAnd here's a video with some tips on making nice looking front panels:How to make professional looking front panels - NFMhttps://youtu.be/lgJ4Z_qLLdUIf you want something that looks like the meter enclosure you pictured, I would search for "sloped instrument case/enclosure" or "sloped console".

author: bifferos
author_rank: Regular Contributor
timestamp: June 06, 2021, 05:35:59 pm
content: There is a pretty good deal on the SC-760 at CPC:https://cpc.farnell.com/snap-circuits/sc-760/snap-circuits-jr-750-experiments/dp/ED00461May just go for that, seems to be quite a lot there for the money.

author: bifferos
author_rank: Regular Contributor
timestamp: June 06, 2021, 05:40:41 pm
content: Quote from: themadhippy on June 06, 2021, 05:03:39 pmThat's a great idea, would be dirt cheap, very easy to work with and just snap together.

author: gtm
author_rank: Contributor
timestamp: June 06, 2021, 06:21:43 pm
content: When I was a kid, I had something similar to this:It uses spring contacts, really easy to interconnect components.

author: ledtester
author_rank: Super Contributor
timestamp: June 06, 2021, 08:08:44 pm
content: Quote from: gtm on June 06, 2021, 06:21:43 pmIn the US they're called "200-in-1 Electronics Lab" or "N-in-1 Electronics Lab" for other values of N.Since they use wires it easier to make your own circuits.

author: Ian.M
author_rank: Super Contributor
timestamp: June 06, 2021, 08:24:29 pm
content: Does anyone know where to get similar springs to those N-in-1 kits at an affordable price? IIRC they are bright-plated tension coil springs with no terminations at the ends, and one or both ends reduced diameter so they can be screwed into a slightly undersize hole in the panel.

author: rstofer
author_rank: Super Contributor
timestamp: June 06, 2021, 09:14:09 pm
content: https://learn.sparkfun.com/tutorials/recreating-classic-electronics-kits/all

author: Ian.M
author_rank: Super Contributor
timestamp: June 06, 2021, 09:26:32 pm
content: Unfortunately Sparkfun discontinued the springs:https://www.sparkfun.com/products/retired/11822Thanks for the link though, as it shows I'm not mad to want some, or at least am in good company!

author: ledtester
author_rank: Super Contributor
timestamp: June 06, 2021, 11:00:21 pm
content: These spring connectors are pretty cheap:And they're even rated for 250V which means they're probably OK for battery-powered circuits:Don't quite understand the location of the "L" and "N" markings, though... not really going to be visible unless you mount them on plexiglass.Aliexpress link:30pcs CH2 Quick Splice Lock Wire Connectors 2Pins Electrical Cable Terminals 20x17.5x13.5mm For Easy Safe Splicing Into Wireshttps://www.aliexpress.com/item/32795734427.html

author: Ian.M
author_rank: Super Contributor
timestamp: June 07, 2021, 01:59:07 am
content: No, those wont help. Think of the difficulty of getting several 24 or 26 AWG hookup wires inserted and gripped by that, which is easy with a N-in-1 spring. Also how many insertions are they ratedfor (or rather how many are the OEM product they are a clone of, rated for)?OTOH if you repair/recycle a lot of mains powered stuff, a pack of them could be handy if you aren't a morning person, to help assessing stuff where the <double-expletive> lead-cutting trash-pickers have got there before you!

author: rstofer
author_rank: Super Contributor
timestamp: June 07, 2021, 02:03:08 am
content: If you have a parts house like McMaster-Carr, you can find spring stock that you can cut down. According to Sparkfun, the springs should be 1/4" OD and 3/8 long. Well, McMaster-Carr has 1/4" OD by 36" long for a few bucks. Cutting to length would be a project but doable. I'm not sure what wire diameter to buy. Knowing me, I would buy a few different diameters and figure it out later.https://www.mcmaster.com/extension-springs/extension-spring-stock-6/

author: ledtester
author_rank: Super Contributor
timestamp: June 07, 2021, 02:52:33 am
content: Well, there's always the old-fashioned Fahnestock clips...Around $0.20/piece at:https://usmegastore.com/product/united-scientific-supplies-fscp01-pk-10-fahnestock-clipsOk -- maybe you have to buy 500 in order to avoid the $15 service charge.

author: tooki
author_rank: Super Contributor
timestamp: June 07, 2021, 06:50:15 pm
content: Quote from: bifferos on June 06, 2021, 03:24:02 pmStäubli just stopped making them sometime in the last year.

author: wizard69
author_rank: Super Contributor
timestamp: June 07, 2021, 07:33:01 pm
content: Back in the day, in high school there was a training system called "LabVolt" that you might be talking about. It appears that the company is now owned by Festo:https://labvolt.festo.com/solutions/2_electronics.My impression back then and frankly it hasn't changed in over 40+ years, is that such systems are a waste of time. It really doesn't matter if you are training for an electronics tech position or more towards the end of electronic/electrical controls, you really should train on materials representative of the real world. That means bread boarding discretes or DIN rail mounted components. I honestly see such hardware doing a disservice to the student.Quote from: bifferos on June 06, 2021, 03:24:02 pmMaking up instruments, power supplies and such is a different thing. Such items need to be properly enclosed and use common connection methods of which banana plugs are one significant method. So while I wouldn't bother to takes this route with circuit components if you are going to make up a power supply or an ammeter then most certainly go ahead. You will learn something with every instrument you build.However there is one big and sad reality, almost anything you build will end up costing you more than buying the equivalent China produced item. For basic circuit inspection cheap multimeters can do the job and you would find it hard to buy an analog movement for the same price new.So the best reasons to DIY, test and measurement instruments, come down to these things:The opportunity to learn electronics. DC supplies, for example, are something every person new to electronics should learn about as they are a common failure point in the greater world.You can actually develop a significant amount of mechanical skill also. This from learning to layout and construct housing for your DIY projects.You MIGHT be able to save money. This especially if you can repurpose other hardware and electronics.You will certainly save money if the device is something that isn't in production or is so specialized that there is a big premium on the retail price. However as a beginner this isn't likely something you need.Well you can show it off. While this might rub some the wrong way it might be useful in a job interview if you can show documents about how you designed and implemented.Recycle an old instrument into something different or better. For example turn a scope into a dedicated curve tracer.QuoteIn all honesty I wouldn't!!!!! At least not for discreets components like batteries, capacitors & etc, as you mentioned. The reality is such systems rub me the wrong way, if I was to train somebody new to the world of electronics, I would want them to be manipulating the actual components as much as possible. If you are teaching students beginning DC circuits make them wire up a set of resistors in series an parallel. Further make them use several methods of connecting those components, including soldering, test leads, breadboards and whatever else you might think up. In the end you introduce needed skills while pursuing the greater aim, which is DC circuits.QuoteWell that might not be what you want to hear, but it is my honest perspective. I remember those old LabVolt systems that really didn't get suitable use. There where a number of reasons, including the quality of the teaching, but in the end I never liked the systems.If you are looking at this as a potential business solution, what might be useful for some schools is a big box of electronic instruments that can't be put into a backpack. That box might be mostly air but if it can keep stuff from walking it might be worthwhile. The reality is though something custom made like this is likely to be too expensive for a public school.

author: wizard69
author_rank: Super Contributor
timestamp: June 07, 2021, 07:43:12 pm
content: Breadboards should be where the bulk of the training takes place. They work well and it gives the user a feel for actual devices. I do however believe that the students should be forced to use different approaches to learn things like perf board assembly and other techniques to cobble up a circuit.As for a more all in one solution, it might be nice to have a breadboard solution with integrated power supplies, multi meter and possibly other devices. I know that in the past you could buy bread board systems with integrated supplies, I haven't looked lately though. For a student, it could be easier to carry around that a bag full of individual instruments.Quote from: RoGeorge on June 06, 2021, 03:45:59 pm

author: RoGeorge
author_rank: Super Contributor
timestamp: June 07, 2021, 08:35:32 pm
content: Just teach the kid to twist the wires with some pliers, or use paperclips for interconnections, or use alligator terminated wires, or just use a breadboard like everybody else.Do not expect the kid to do, or to like, exactly what you did or liked back then. Times change and now the tech is very different. The fascination feeling will be the same, just that that will be for other items than those that once fascinated you.Or, even worst, the fascination might come from no items at all. I mean from software.And if you think piling up lines of code is not as fun as piling up wires and parts, just wait for it! It can be even "worst" than that. The kid might get fascinated instead by piling up data, and training a neural network in the cloud.You think that would be horrible? Just wait for it, it can be even worst than the worst of the worst, the kid might not be interested at all about it.Maybe instead of pre-building a lab, let the kid build own lab, in time, piece by piece, and guided by you. My point is, don't try to build a lab in advance. Just use a (preferable transparent) breadboard and a couple of LEDs, then see how it all unfolds from there.Good luck with it, both of you!

author: Electro Fan
author_rank: Super Contributor
timestamp: June 08, 2021, 05:37:43 am
content: Quote from: bifferos on June 06, 2021, 05:35:59 pmGo for the Snap Circuits. Be prepared to do some teaching, guiding, encouraging, helping, and playing. The Snap Circuits kit will help the student learn some terminology and concepts and give some visual and audible feedback while keeping the student physically involved with some repeatable skills (snapping to the grid). It will probably help keep the student involved with learning at least until they learn some math, and then it will open another layer of insight. It’s likely a 7 year old is learning to count, add, subtract, and maybe multiply and divide but algebra is not likely happening just yet. So rather than learning the math of Ohm’s Law the student might possibly start to see the concepts of voltage, current, and resistance - but these are more likely to be absorbed if the student can see something tangible (lights, sound, etc) which they will get with some of the Snap Circuit projects. If the student shows interest as they learn to make the various projects (which are nicely illustrated in the booklet), then you can provide a $10 DMM so they can learn to measure volts, ohms, and amps. Measuring doesn’t require doing the math but it can help students see the relationships that can lead to and reflect the math. I think the Snap Circuit kit you are looking at might keep a 7 year old involved from time to time over a period of a couple years and maybe a few years, and then it can be handed over to another learner. Ideally you will get at least 1-2 laps with the Snap Kits, and maybe 3: i) the fun and positive reinforcement of learning some words and concepts that really make something with the projects, ii) the opportunity to measure with a DMM, and iii) the opportunity to teach the math of Ohm’s Law. If all that happens by middle school it will be a very good success and well worth the price of the kit.

author: rstofer
author_rank: Super Contributor
timestamp: June 08, 2021, 03:30:40 pm
content: Quote from: wizard69 on June 07, 2021, 07:33:01 pmAmazon has analog V-O-Ms for as little as $10.https://www.amazon.com/s?k=analog+multimeterI like analog meters, I still have a couple of Simpson 260s and use them from time to time when I'm in an analog mood. Otherwise, I probably grab my Aneng 8008 (instead of one of the other DMMs).

author: Renate
author_rank: Super Contributor
timestamp: June 09, 2021, 12:20:16 pm
content: I started with (Raytheon) Lectron little plastic cubes on a metal ground plate.https://lectron.info/I had plenty of 100-in-1 spring on cardboard kits.The RTL Microlab used something different, metal posts and little clip wires (that you had to make up yourself).

author: bifferos
author_rank: Regular Contributor
timestamp: June 19, 2021, 09:47:41 pm
content: Just to let you know he's really pleased with the snap circuits and has raced through dozens of layouts in the first day. I don't know (and don't really care at this stage) how much he's understanding but he's clearly having fun.

author: rstofer
author_rank: Super Contributor
timestamp: June 20, 2021, 01:31:33 am
content: Quote from: bifferos on June 19, 2021, 09:47:41 pmAbsolutely outstanding!Later on perhaps he will want to play with Arduino experimentshttps://www.amazon.com/ELEGOO-Project-Tutorial-Controller-Projects/dp/B01D8KOZF4

author: wizard69
author_rank: Super Contributor
timestamp: June 20, 2021, 02:34:37 am
content: Quote from: bifferos on June 19, 2021, 09:47:41 pmIf it isn't fun there really isn't much of a point. Glad to see things are working out for you. I'm not sure if this student is ready for theory but it might not hurt to spend 1 hour a week going over theory. This just to make sure he has the basic DC concepts right. Just don't turn the whole thing into an extended school session.