Suggestions for aspiring hobbyist

There must be a million of these posts on this group and I apologize in advance if I'm violating some rule.

I come from a computer science background and I'm now looking to get into electronics as a hobby. I have a few ideas for circuits I'd like to construct eventually, most of which revolve around various sensors and audio processing. One specific circuit I'd like to build a sample & bit rate reducer for an electric guitar or bass signal with a CV-controlled LFO to control the intensity of the effect.

Anyway, I've been reading books by Forrest Mims and also /Electronics for Dummies/ at the book store as well as various internet sources for additional information. Some sources claim /The Art of Electronics/ is a necessity while others say it has entirely too much information and the wrong approach for a hobbyist. I don't want to just build pre-made kits or copy other people schematics -- I'd really like to make new and original things happen. I have plenty ideas, but I seem to be stuck in the CS / software point of view when it comes to construction. I can build an entire program in my head for the aforementioned sample rate reducer, but I just can't see envision it in components. I assume I'd need some sort of analog signal to digital signal converter and an IC chip to do the real work of the problem... but I really have no idea.

I already have some preliminary equipment (solder iron, desoldering braid, thin pliers & cutters, wire stripper, 20 AWG solid wire, digital multimeter, etc) but no actual components or breadboard. At this point I am sort of sold on the dead-bug style for educational / experimental prototyping.

So does anyone have any suggestions for me at all in anything I've mentioned? I find myself wanting an expert electronics guy around to guide me, but I don't know anyone, so I turn to internet folk. Any material to read, sources to look up, comments regarding /The Art of Electronics/?

Thanks!

Reply to
sly.psi
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schreef in bericht news: snipped-for-privacy@75g2000cwc.googlegroups.com...

Guess you're trying to start too high. Among the skills you need are knowledge and experience. You apparently lack definitively the latter. So search the net to find some things you want to make. Build the thing and find out how it is suppose to work. (You'll have to because it's unlikely it'll work the first time.) You can search for almost everything because there're a lot of circuit designs out there and there is no use in reinventing the wheel. Next step, if you can't find exactly what you want, is to modify an existing design. Designing somthing new from scratch is the last step. It's like inventing. Creativity is indispensable but it's only

10% of the work.

petrus bitbyter

Reply to
petrus bitbyter

snipped-for-privacy@gmail.com wrote in news:1155196425.535182.116970@

75g2000cwc.googlegroups.com:

*snip*

Same with me. I *know* what makes a computer tick. ;-)

*snip*

Electronic design seems to be able to be done like some software design. Learn what the little parts do (fprintf, streams, etc) and put them together.

Look in to a starter kit. Avoid the Radio Shack 120-in-one ones, though, they're ok, but not half as fun as playing with a handful of parts. Look for digital logic chips in the kit, too. With your background, they might be the things you understand first.

Learn to solder. Learn to unsolder. Practice, practice, practice. You'll get some places where your soldering skills will be necessary to prevent wrecking a $8 chip...

You're welcome.

Puckdropper

--
Wise is the man who attempts to answer his question before asking it.

To email me directly, send a message to puckdropper (at) fastmail.fm
Reply to
Puckdropper

Read some theory, build some kits. (what is the hangup with kits? too demeaning to follow someone's lead?) Electronics is usually taught by theory along with building some circuit that supports the theory.

Do what interests you. There is no one book that is magic, and no one approach that will be right for everyone.

You seem to be looking for a shortcut that will catapult you from zero to master designer - probably won't happen that way - electronics encompasses a lot of knowledge. No one is expert in all of it.

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Reply to
default

I know the feeling. I have a lifetime of experience and training in electronics and a Computer Science degree. What I want today is a coupe of pills I could take to become a Linux Guru and a Java programmer. Unfortunately, it appears there are no pills available. I will have to decide if I want to expend the effort to reach those goals in the conventional manner.

If you find The Art of Electronics interesting consider the Lab manual that goes with it.

I have taken one course from

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and found it well worth the cost and time. The ARRL is an amateur radio organization.

The only short cut to your target device I can think of is that you might look into microprocessors. There are many development boards available that can be extended and programmed to do some pretty exotic things!

Bear in mind that with my background I considered building a miles per gallon computer for my RV. After researching the time required I ordered one off the net. Sometimes it makes more sense to buy it if it is available!

Good luck,

John, W8CCW

John Ferrell W8CCW

Reply to
John Ferrell

First of all, you can approach most circuit design like you'd approach software design... with building blocks of tried-and-true modules. You start out (as you probably did in software) learning new modules and adding them to your bag of tricks. With circuits those will be Basic Op-Amp Buffer, Inverter/Summer, Integrator, Filter, Comparator, Sample/Hold, etc, etc. You will also learn about the capabilities of various logic chips like Flip-Flops. Don't worry about copying other's circuits... learn from them. Figure out what building blocks they are using and why. Then you can make changes to suit your own needs.

Get a solderless proto-board. These are absolutely indispensible for working out new designs.

One of your first soldered projects could be a bench power supply. For the kind of things you are interested in, you will need to be able to power op-amps as well as digital chips. I'd recommend CMOS for the digital, as it is easy to interface to the analog and you can find versions that work on 15V. You can make your bench supply put out +/-15 and carefully interface the logic to use only +15. Or you can make it +/-7.5V and put the CMOS across the 15V total when needed. You'll want to do this for switching analog signals with CMOS gates like 4051, 4052, 4053.

Now about your desired project: I'm not sure exactly what you have in mind with a "sample and bit rate reducer" for a guitar. Are you trying to pitch-shift? If so, this is non-trivial (beginner or not), because you have to either fill in missing data or chop out excess data... either one causes nasty splicing noises unless done with great finesse. (If you speed up the output rate relative to the input, you will quickly run out of input samples and have to fudge some from somewhere. Advanced schemes attempt to determine the period of the signal and copy just the right portion, but even still you have to chop it off at some arbitrary point if you have an arbitrary rate shift from a VCO. Similar problem in slowing down.)

For a beginner, I'd recommend starting out with some purely analog projects that don't require computer interfaces. Look into phasers, multipliers, and distorters. (Distortion can be done lots of different ways, including subtle colorations, not just full-tilt "Fuzz".)

Best regards,

Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis

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Home of DaqGen, the FREEWARE signal generator

Reply to
Bob Masta

Buy some hobby mags to begin with. Just about everyone started there.

I'd advise not trying to run before you can walk. First off you need to acquaint yourself with the practical aspects of construction and circuit design.

Graham

Reply to
Eeyore

I got my son the Radio Shack Electronics Learning Lab. This is a combination sprint-parts and breadboard lab, with both analog and digital books and parts (including op amps and PLLs). I use it a lot for testing out designs, and I've used it to program eeproms by running a ribbon cable from the parallel port of my PC to a female header connector (i.e. mini-breadboard :) and building an eeprom to DIP converter that plugs into the breadboard.

Another idea: get an eval kit for a microprocessor that happens to have A/D and D/A on it already (most do) which happens to have a breadboard or prototyping area on it.

Reply to
DJ Delorie

One hobbyist to another: Get a copy of Grob Basic Electronics (cheap if you find it at a used bookstore or used online. Get the latest edition you can reasonably afford.) Make *certain* you understand Ohm's law-that is something you will *never* get away from. If you are interested, email me and I will send the schematic and text of an article from an old Popular Electronics magazine for a simple but very useful and educational but small project; an in-circuit transistor tester (works on jfet's and any other kind of transistor I have ever tried it on, not just the standard general purpose bipolar small-signal types. It comes in handy 'cause you don't have to take the transistor out of the circuit to test it, and troubleshooting broken devices is one of the best ways to learn (my opinion.) I haven't read The Art of Electronics, but I would wait on it until you have a breadboard (protoboard?) and a few small projects under your belt. Until you understand the fundamentals, even slightly advanced texts will just be confusing. NOTE: Never try to plug a wire or lead with solder on it into your breadboard. The solder will hang up on the internal connector strip and tear it up when you try to pull it back out.

You already have a multimeter, and that's good. Think about a cheap (Hah!) oscilloscope. Not an absolute necessity until you really get into things, but certainly usefull. If you are working with digital logic, it will be worth its weight in gold. And when you do get one, make sure that you plug it into a properly grounded power receptacle, or you can blow it up if the project you are hooking it to has the "hot" and "ground" wires reversed in the powersupply. If none of this makes any sense and you can't seem to figure it out, then just plug it into an isolation transformer before hooking ito to your project.

I am no expert, but I maintained and repaired state-of-the-art high-speed printers in a mainframe computer environment and other less exotic equipment for twelve years, and have been into electronics as a hobbyist for the last twenty-five years. My latest project was building a preselector/RF amplifier for shortwave listening from the schematic in the back of a commercially produced user guide (MFJ 1020-A). This devices is also called an "active antenna" because it takes the place of a much larger antenna and filters out noise before amplifying the signal and sending it to an attached shortwave radio. I built this almost entirely out of junk parts and surplus, and added a couple features like static discharge and positive tuning indication (tells you when you are tuned to the exact frequency you are looking for). I also recognized and removed from the circuit a bit of deliberate sabotage that would have kept it from working, and even modified it to cut its power consumption by +/- 90% so the batteries last longer. I really am no expert however, just someone who has been poking around for a while. Most of the other people here know a lot more than I do.

Feel free to email, and I will reply via my "real" email address. I can even look around and see if I have a spare (working) oscilloscope to help you get started.

PS Does your multimeter have a frequency counter built into it? Or a transistor tester? What about capacitance metering? If not, look for one that does these things and keep the other one as a spare (you will eventually need a spare). I got mine for $40.00, brand new, at my local parts outlet. It's an off-brand, but it works fine.

Good luck. Don't be afraid to ask questions. They open doors.

Sorry to be so long-winded. :)

Dave

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Reply to
Dave

My interest developed after reading various little project books that were sold by Maplin (in the UK). I think they helped because they deal with stuff in bite sized chunks. I already had a fairly good grounding in electrical stuff, and some shaky electronics knowledge. If you don't have that, then basic reading on things like Ohm's law is essential.

Get a breadboard and components sooner rather than later. You can get a fixed-size board, or you can get several little boards that interlock (letting you expand the board in any direction if your circuit starts growing). A good way to get started with components is to buy multi-value packs of basics like resistors and capacitors, along with other common bits like LEDs, diodes, transistors. Buy the cheap things in packets of several (some will get fried). Some little switches that fit the breadboard can be handy, and cut-to-suit rows of turned-pin PCB header can be used as plugs for connecting wires to sensors.

I would add a power supply - a twin-rail one will let you play around with op-amps. You can build a basic one with no panel meters cheaply, and it's not too hard (but you have be mindful that it deals with nasty bad mains electricity).

If you can, get an oscilloscope. There's nothing quite like it for seeing what's going on inside a circuit. If you're interested in audio, some sort of signal generator will let you inject a known signal into a circuit, the effects of which you can then view on the scope. With a twin-trace scope, you can directly compare the input and output signals - at any two points in the circuit (IOW, not just at the sig-gen and output socket).

In my experience as a relatively clueless n00b, I would say the scope is one of the most essential pieces of kit. It vastly speeds the get-it-working time and prompts learning - you have to understand the circuit to know what you should see on the scope, so that you can tell if you've got what you

*should* have. And if you haven't, you can see what's different about it, and start to work out what part of the circuit is causing the difference.
--
Melodolic Spielberg
Reply to
Melodolic

What's wrong with using other people's circuits? When you need trig functions in a computer program, do you roll your own or just load up math.h? You think professional engineers never use a recipie book or the application notes in the data sheets? Some are used often enough and are important enough that they even have names, like the Butterworth filter or the Chebyshev filter.

Think in terms of block diagrams-- what do you need to do (functionally, not component-wise) to turn an input into the desired output? Then you'll need this amplifier, that filter, an oscillator here, a rectifier there... Consult appropriate references to find appropriate amplifiers, filters, and etc. that other people have built, understand the circuits well enough to know whether they're suitable for your application (you'll have to adjust some component values to get the desired gain, 3 dB point, and so on), and then just go ahead and use them. Designing your own circuits will come with study and practice.

And The Art of Electronics is awesome. H&H do as much as anyone can do to make electronics theory an entertaining read.

Reply to
Greg Hansen

You've already gotten plenty of advice for where to get proper knowledge, so I'll skip that. All I'll say is that if you read 3 pages of The Art of Electronics a night, you'll know just about everything you'd need to know in a year. But experience is often more helpful than knowledge, so just start out with some simple, cheap, and easy circuits.

As for the circuit you want to make, it's rather easy. You don't need to use any kind of analog/digital/analog conversion at all. A Sample & Hold can be thought of as a primitive ADC -> DAC that uses a capacitor to store a voltage and a high/low trigger to switch between sample and hold modes. For the exact thing you want to make, see here:

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It's an effect that I myself like quite a bit and have made using that very method. You can get a somewhat similar effect by performing amplitude modulation using a square wave, but the S/H method will give better results. The chip can be sampled for free and the rest of the circuit is trivial.

Now for more control, and perhaps bit-depth adjustment as well as sample-rate adjustment, you can make a much more complicated circuit or even use a microcontroller for audio processing.

Since you are a computer tech, you may want to use microcontrollers to bridge the gap between computers and electronics. A microcontroller is simply a microprocessor with input and output circuitry built in. There are many options: PIC, BASIC Stamps, Atmel AVR (my preference) and others. For a cheap introduction, I recommend this development board:

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You'll get the whole development board plus programming cable for about $40. Futurlec is very slow to ship, but the board is fantastic for the price. Then you can code in C or the native ARV assembly language (other compilers are available, too).

This way you can combine your love of coding and computing with your new found interest in electronics.

Good luck!

Reply to
Tavys

Oh, and while I'm at it, I should mention that you should consider joining up with that electro-music.com forum I gave the example from. The DIY synths and Modular Synthesis sections will provide you with lots of examples to experiment with. Since you mention CV control of an LFO, I assume you understand a little bit about synths.

Also, the LFO could control several things including the sampling rate and the effect intensity (and by that I assume you mean the mix between the original signal and the effected signal). An Ernie Ball volume pedal can be used as a CV pedal if there's no input plugged into it, so you've got your foot control right there. All you'd need is a VCLFO and you're set.

Have fun!

-Tavys (p.s. I'm bigtex on the electro-music forums, if you decide to seek some help there as well)

Reply to
Tavys

Guitar effects have historically been a popular hobbiest project :)

what's a "sample rate reducer" It feels like you might be wanting some sort of "switched capacitor filter".

I don't underrstand exactly the effect you're after... but that's always one way to go after it.

Bye. Jasen

Reply to
jasen

I'm mostly self-trained, as the only courses on electronics I've taken were one year of electronics drafting (at Tektronix, at a point when I understood rather little about anything electronic) and one single short class on BJT circuit basics (also at Tektronix, mostly a short course of testing one's ability to get roughly close to the right voltage values on some small, sample circuits.) These, at roughly age

27, around 1982. Before this, I had had to learn digital logic basics and a vague idea of some analog rules of thumb in order to fix some 4k dynamic RAM cards I paid dearly for from MITS and didn't work, when assembled. I had spent just about everything I had in getting those two boards, and then some, and was terribly pained to have them not work. Since I'd assembled them (sold as kits), I didn't feel I could send them back, either. After I figured out how to make them work, I'd learned a lot and _then_ received a blanket letter to all owners, from MITS, saying that they had some design problems and noting the fixes (which I'd already handled.) That hard lesson on dynamic ram and the few courses I mentioned are all that I had at the time.

Not many years later, in 1985 I think, I took on the personal challenge of converting my IBM Electronic model 85 typewriter into a printer. For that, I used an 8031 processor, a static ram chip, an EPROM, and set about figuring out the relay combos used and set up a table. I wire-wrapped my design and then wired the 8031 system to the keyboard in a reversible fashion (didn't want to destroy the typewriter) and set up the software for handling RS-232 input, buffering, timed driving of the various relay inputs to the typewriter, and so on. Worked first time! My first real, practical design. A printer I used for quite some time, too. And it still worked as a nice typewriter, as well. When I sold it, I simply removed the wiring (I'd used a ribbon cable pinched by the typewriter case, without cutting the case in any way, for the RS-232 connector so the operation was completely reversible) and I still have the box and processor board in a box in a closet.

However, I'm still able to only muster up a modest understanding of most things. I have a few things I know well, but the broad experiences I still lack as this isn't my business and, perhaps, I'm not as smart or creative as some of those who make a profession of it. That's okay.

Anyway, my experiences above are NOT a recommendation for how to pursue electronics as a hobby. It's just part of how my own experiences played out. If you can find it, an education is worth having and a good education is priceless. Look at community college courses as a possible option and take them, if you can manage it. I still imagine taking courses on electronics for pleasure, someday.

It's really important to have some specific applications in mind, just as you mention, because trying to achieve them will drive you. I learned more math than I was getting in high school, as a teenager, because I wanted to design my own telescope. I had built a Newtonian from someone else's design and I wanted to learn the details of design and come up with one more to my specific tastes, at the time. This meant a cassegrain, as my second; and then for my third 'scope it was a Gregory/Maksutov, without complex curves that take more time to make and test.

But aside from specific end-results, are you also interested in how things work, too? Because if you don't have an abiding interest in dismantling doorknobs, TVs, your car, and just about everything else you see around you -- just to see what makes them tick -- then you may find yourself tiring of the endeavor over the long-haul. At least, if no one is paying you for your interest (which means 'hobby'.) You really need reasons other than just a few end applications themselves to stay involved.

I enjoy dismantling things. And the nice thing is that when I put them back together again, I have all these nice, spare parts left over, too! ;)

Used to be good articles found in several electronic periodicals, once in a while. I'm not sure what modern magazines might now offer, though. I used to follow Ciarcia's column in BYTE. But a lot of what goes for electronics projects in magazines these days doesn't spend the time to teach as much as once they did, I think. Maybe I'm wrong about that.

One source for developing basic knowledge came from either Heathkit (back in the day) or similar training kits that usually started with DC basics, then went on to AC basics, then to ICs and general design. Also, the training books developed for military (the ones I saw and spent some time with were for WW II) weren't too bad, either. Lots and lots of material to keep slogging through, if nothing else. I suspect that there are good training systems still available -- though at what cost, I don't know.

It's both and neither. It will have way too much information in many places and then also just the right amount elsewhere. I'd recommend it --especially if-- you also get the student manual for it. And maybe still, if not. But some things in AofE are a big help and will be there later on when you are ready for it, too.

Because of your software background, you may also eventually want to consider the idea of doing projects that are "embedded" and use a microcontroller, instead of just analog electronics. But don't neglect analog, either. But take it slow and don't envision the really big ideas until you've managed to completely master some fairly basic things.

Just as in software design, electronics is often more easily handled by breaking down the functions into tight groups of parts with a small number of inputs and outputs. Within the function block, there may be many intimate relationships, but between them the concepts should be fairly simple and easily understood. You will need to master these various function blocks a few at a time and build your repertoire. As you do that, you will find that you can tease apart more complex circuits by first recognizing sections and eliminating them while you focus on the rest. To begin, most of it won't make any sense as you won't have enough blocks to make any headway at teasing apart all the rest. Later, you will find it much easier to tease them apart and will then know which areas you _don't_ understand or know anything about and you can then focus your questions to others onto those areas. Much faster for everyone, then.

In addition to other possibilities, you might consider the idea of getting a prototyping board with a microcontroller on it already and with access to pins on which you can "add stuff." Sometimes, that is a good way to get thinking about BJTs and MOSFETs, for example, because you can use them in one of their simplest modes -- a switch. And with the software, you can try out different ideas. A 'scope starts to be important, about this point in time, though.

Some things you can easily learn yourself. Ohm's law is like that. The conservation-law based ideas of Kirchoff are easy to understand the theory of (sum of currents in and out of a node must be zero [or else electrons would be jammed together or sucked out, over time] and the sum of voltages around a loop must be zero [the voltage must be the same voltage when you get back to the same place]), but it took me a little practical work to develop a practical feel for actual cases and to start thinking more in that mode. A detailed understanding of BJTs will take more time -- starting with the forward biased active mode and some gross simplifications that get you often close and then proceeding to more refinements as you are able to assimilate them. For example, it wasn't until later that I began to realize the cause and effect of B-C and B-E capacitances in the BJT and some methods of overwhelming them quickly when speed is needed. And getting deeper understandings of various parts will probably never stop -- at least, hopefully it won't.

There are some nice proto boards for cheap, recently. They are global specialties solderless boards and the ones I found were similar to the PB-102 and cost me, just last month I think, about $14 each. I forget where, but I could look it up. They are nice to use.

I also find wire-wrapping useful. So you might consider the idea of that, as well.

An oscilloscope will be useful, if you can get one. And these days, they are a LOT cheaper than they used to be when I was desperate for them. They are available readily as used, too.

It's always better if you can find someone to help. Lacking that, you will just have to try. There is the internet now, so that is a plus that didn't exist when I was struggling hard in the mid-1970's. Take advantage of it, as you are. Other than that, just get started doing some simple things and try and master them and various ways of looking at them before going on to much more complex things.

Jon

Reply to
Jonathan Kirwan

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