Prototyping system

Solderless breadboards are okay for audio, with care. Even 20MHz micros if you don't do stupid things.

SMT parts can be converted to 0.1" pitch through-hole with breakout boards.

All he needs is a sturdy kitchen table, 63/37 Kester 44 solder, good soldering iron, wick, and some AWG30 solder-through magnet wire to make more permanent circuits using perf board. All the necessary tools and supplies can fit in a shoebox when not being used.

--sp

--
Best regards,  
Spehro Pefhany 
Amazon link for AoE 3rd Edition:            http://tinyurl.com/ntrpwu8

I suppose that's true. I guess when one has a bench that looks sort of like Jim William's, one forgets that it doesn't have to be that way. 8)

When I was getting started I looked into Veroboard, that stuff with tracks underneath where you design the layout with some software, and then selectively cut traces on the underside. Even then the effort involved seemed about 70% of that required to design a full PCB, and not really worth it.

The method I've used for audio/low frequency for years is just run power and ground blobs on blob board, connect up the most critical "traces" with blob runs, and then connect everything else using very thin solid core wire, like 32 gauge, on the underside.

He could probably use an oscilloscope; I have too many analog scopes anyway. The old 60Mhz Kikuisi from ~1982 still works great, but then again it's a beast and he'd have to find room for it. 50Mhz digital scopes are relatively inexpensive these days, so if he can swing it that should probably be his next purchase.

Everything you need to make an FR4 proto board, including some tools and a soldering iron, will fit in a shoe box. He'll need some test equipment anyhow, which will take more room.

Planning a layout, and soldering, are good skills to develop anyhow. The white plastic things destroy peoples' brains.

Speaking of layout, we're doing a board now. There is high-speed and placement/cooling critical stuff, and I can't find a way to communicate all the constraints to my layout guy, so I'm doing the critical placement myself. It took me about 10 hours yesterday to place 4.5 square inches of board, 87 parts. Today, I'm doing another section, another 60 or so. Placement is important and tedious.

Your friend should learn to map a schamatic into a physical arrangement. The plastic things wreck the art of doing that. And learning to solder is great.

I like to breadboard on FR4. That requires a lot of chip adapters (like the Bellin things) and optionally a Dremel.

Do you think this kid is serious about electronics? I'll donate parts and stuff if he is.

--

John Larkin         Highland Technology, Inc 

lunatic fringe electronics

4"x4" square of pine wood and some screws with pressed countersunk washer (use Google image search). Draw the schematic on paper first, and put screws into each junction before fitting (leaded) components.

Clifford Heath.

A biscuit tin is good to contain everything, being metal it's good as a soldering desk/tray. Some perf board with copper pads should do the job, you can get packs of small pcbs like that from China very cheaply. You don't need FR4. Or wick.

Parts can be salvaged from junk, kids don't generally need to buy much if anything now.

Save a few wallwarts to power stuff.

Cheap multimeters are very cheap. Don't bother with a nice one until he knows what he's doing, it won't survive long term.

NT

For a beginner (or even for me :^) I sometimes use sockets with the perf board. That way if something blows up or doesn't work right you can change opamps and stuff easily. In the past I would even use sockets to change through hole resistor or capacitor values.

George H.

I'd say that his real bottle neck is not proto boards but test equipment. He has to be able to see what's happening. A good-enough DMM for $40, but people are visual creatures and there is nothing like a scope for knowing what's going on.

When there's no room for a real scope, there's PC/laptop-based ones. Every student has a laptop! Daqarta, picoscope, etc. Bob's (not me) your uncle.

Bob

I hear it's easy to kill the soundcard with those.

Dead bug construction also has its place. As does hardwiring for some simpl e circuits.

NT

Not really as long as you keep your input levels reasonable. All the sound cards have capacitor coupled inputs, so there's little chance of giving it a static electricity blast or 117VAC surprise.

However, I want DC coupling and didn't want to butcher my laptop. So, I got a cheap USB sound dongle and modified it. Something like these: and modify them per various instruction found on the web: I bought several of each expecting to blow them up occasionally, but so far, other than breaking off the USB connector a few times, I've seen no failures. If you're worried, use a dongle or external USB adapter.

Also, I've taught a few students how to build breadboards. Usually, it's a 0.062 single sided PCB, with components attached in a 3D manner. That's really the trick to building a prototype. Never mind trying to make it 2D and look like a finished product. Build it up in three dimensions, or even layers, and make it work. Rev 2 can be made to look pretty. Even RF can be done this way, since having an effective grounding system is critical.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

:) Cars are't a hazard either, as long as you don't hit anything.

a strange nonsequitur.

a better plan surely. It at least reduces the risk to a degree. Use a low value computer too.

NT

I think Veroboard is pretty good for getting started and smaller one off projects. Much less hassle on a domestic scale than fighting with photoetch chemistry and drilling. I did it both ways in my youth.

Solderless breadboards are OK provided you don't do silly things with them or try to use fast parts. My first ever Heathkit? electronics kit used washers soldered to springs and split pins which went through perforated hardboard to make its connections. Assembling something correctly without having any shorts was a real challenge?

For an impecunious student and at mainly audio frequencies Daquarta using a PC sound card is hard to beat. You get 30days free trial and can keep the signal generator bit whether you buy the thing or not.

--
Regards, 
Martin Brown

Use the free scopes, sig gens, vector scopes etc instead.

NT

Presumably, one has some control over the automobile and the sound card input levels.

OK, I confess. I'm wrong. The typical 1uF(?) sound card input cap doesn't offer any protection. Two back to back diodes with a series resistor to the input should help. Or, clamping diodes to +/-5V or

+/-12V should also work, if the negative voltages are available. Using a x10 scope probe also offers some protection.

Methinks these modifications are within the limitations of a beginner, especially if there's no room to install a proper oscilloscope. However, if size is important, there are cheap oscilloscope kits available:

200KHz bandwidth is probably good enough for audio (and it does DC). Might as well throw in a components tester and ESR meter: Soldering together some of these type kits might be a good way to get started.

I repair computahs, so all my 2nd hand junk, usually acquired from customers after upgrades, are low value computahs. However, I still prefer external USB sound dongles to avoid "Learn by Destroying(tm)".

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558