Thinking about getting back into the hobby

Discussion in 'General Electronics Chat' started by spinnaker, Nov 5, 2009.

  1. spinnaker

    Thread Starter AAC Fanatic!

    Oct 29, 2009
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    My education is in electronics (technical school). It is how I started my career but that eventually morphed into computer programming, which I do today.

    I dabbled with electronics as a hobby years ago. I built a couple of power supplies, an RS232 interface for the Atari computer (including programming the OS driver and repaired televisions (back in the days when it was really easy, all tubes) for some spare cash.

    I'm still fairly young (just turned 50) but I was thinking I need another hobby I can carry on into my later years to help keep the mind active.

    So I am thinking of renewing my interest in electronics. I'll probably be more oriented to the digital side if the hobby but would probably mess with some of the analog side.

    I have a few questions.

    1. What should I look for is a scope? I was thinking of something used, don't want to spend a whole ton of money but also want something useful.

    2. What is the state of the art in circuit board production? I see there is software available but do I really need to send out the file to a company to have them do it for me or can I do it myself? Can I just print a transparency somehow and use a photographic process? I used to use those stickons years ago. I was wondering if it can be done today using a printer. And what about silk screening? Can that be a DIY project?

    3. What do most people do with their projects? Do they build something just for the challenge then tear it down? Or do you actually use your projects? There is not much I can think to build right now. But just a couple are a bench PSU and a AM/FM radio to record on MP3. After that I can't think of what else to build.

    4. One other interests I have is bicycling. Say I happen to come up with a new bike computer with several ICs. Are there companies that will place that all on a single chip for me or do I need to design the whole chip from discrete components?

    Sorry for all the "newbie" questions. :)
     
  2. bill l

    Member

    Oct 11, 2009
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    i can offer some suggestions about test equipment...

    on a side note: cough, test equipment forum, cough....

    moving on, i have gotten back into messing around with digital/analog after about 8-9 years of purely rf/antenna related work. i have since learned over the past few weeks, that some of it is coming back, while other bits and pieces are confusing me. but, i'll get through it i am sure, albeit, i certainly am not currently able to keep up with some of the discussions here.

    in regards to test equipment, you can do the following:

    search craigslist. i picked up a tek 2246a scope for less than a 100 using that.

    do a local search on ebay in the test equipment category. you will most likely find local liquidators selling this stuff and if they have a brick and mortar, they may sell you the "broken" stuff that you may be able to repair yourself for cheap. if you have some known standards, you will be in good shape. i have picked up a couple of fluke bentop meters and a couple function generators for less than 60 this way.

    that is about all i can offer.

    good luck and welcome!

    bill
     
  3. SgtWookie

    Expert

    Jul 17, 2007
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    BTDT! Welcome to AAC. Good place to hang out.

    This hobby will do that to you. ;)

    Well, "it depends". I bought a couple of older 'scopes on an auction site for next to nothing. Both had problems, but the advantage of the older scopes is that you can actually fix them yourself, as long as the tube is good. Not so with the new digital stuff; you can't even calibrate them without spending a boatload of cash for the software. The newer digital scopes have some awesome capabilities, but you can sure spend a ton of money on them.
    [eta]
    If you look to buy on auction sites, watch the shipping costs. I won an auction for a scope where the scope itself cost me $5, but the shipping cost $35. That was a fair shipping price (those old boatanchors are heavy y'know) but shipping prices have skyrocketed since then. Many unscrupulous sellers will "pad" the selling price with artificially high shipping rates, so beware.
    "State of the art" nowadays is SMT/SMD - surface mount technology/surface mount devices. Smaller than the thru-hole and DIP parts.

    You CAN do some boards yourself, if you have the patience. You'll generally get better results if you have them done at a PCB house, but sure - you can do one-offs at home. A fellow by the name of Tom Gootee (who's a member here) put up a web page on how to make homemade PCB's using a laserprinter , photo paper, and muriatic acid combined with hydrogen peroxide.

    That page is here: http://www.fullnet.com/~tomg/gooteepc.htm

    The technique is well suited to single-layer boards and SMT components.

    There are a number of freeware and low-cost schematic capture/board layout software packages. I've been using Cadsoft's Eagle for awhile now; it's quirky to get used to in the beginning, but quite powerful. See the Electronic Resources forum for other suggestions.

    On here it runs the gamut from just getting an LED to blink on and off, to rocket launching systems, large scale trains, battery charging/maintenance, power inverters, just about anything you can think of. Some are pretty interesting. As you'll see, many of the projects could be accomplished quite simply with a microcontroller and some clever coding.

    You need to look into microcontrollers. Like, right now! ;) Have a look at Microchip's PICkit 2 Debug Express, about $50, comes with a PIC16F887 on a prototype board, integrated development environment software, PICkit 2 in-circuit programmer. Cheap way to get started. The PICkit 1 is around $35, but you might feel too limited with it; it only supports DIP PICs up to 14 pins. The PIC16F887 has 40 pins (DIP) 44 pins (SMT) and has an internal 4MHz clock; if you want you can use an external clock source up to 20MHz. Assembler and a limited version of C (2k of code) are included with the integrated development environment.

    We specialize in "n00b" questions. ;)
     
  4. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    I will quote that since it sounds like it is Directly down your alley with the programming side track!

    Some people who use microcontrollers don't know anything about electronics, but can build fairly decent line following robots by brute force with code!

    Depending on your language background, you may want to look at PIC (Assembly, C, Basic, Pascal, and others), AVR (Assembly, C), or "controller boards" that have extra I/O and programability built in, such as the PicAxe (Basic like language) or Arduino (C like language). Getting started is a $50-$80 ordeal, no matter the platform (PIC or AVR based). Read around a bit before deciding what you'd like to do.

    Microcontrollers have brought many of us that grew up with Lawn Darts, The Dangerous Erector Sets, etc. back into electronic projects.
     
  5. spinnaker

    Thread Starter AAC Fanatic!

    Oct 29, 2009
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    Thanks everyone.

    Yes I will probably look into micro controllers. I used to work for an environmental control company (where I was a technician). I left and a few months later the company went kaput. Shear coincidence I assure you. :)

    Any way some coworkers of mine took started their own company and took up the maintenance on the existing systems. They knew I had taken up programming and contacted me. To make a long story short eventually I wrote an environmental control system for them. I was able to unplug the huge PDP 11/34 running the works and plugged in a PC in it's place. We saved the customers a TON of money using the existing hardware and wiring. It was so cool to type in a command and listen to an air handler first be turned on by my software then off again!

    Anyhow back to test oscopes. How many channels do I really need for my projects and what resolution? Do I really need 100mhz?

    I doubt craigslist is an option. I come from a small market (Pittsburgh). I really would not trust buying remotely through craigslist.
     
  6. SgtWookie

    Expert

    Jul 17, 2007
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    Yeah, there's a mind-boggling array of microcontrollers (uC's) out there nowadays.
    PICs can be somewhat of a pain, because source code isn't necessarily portable between families. However, they have a practically mind-bogglingly broad range of uC's with a huge range of features to choose from for whatever application you have in mind. If you're thinking of eventually taking a product to market, this is the way to go. Many of their uC's cost under $1, even in small quantities.

    Atmel AVRs enjoy popularity because the source code IS quite portable up and down their product line.

    At the other end of the scale is Parallax Inc's Basic Stamps. Those things are pricey and slow, but very popular in the academic world. Programming is in a Basic-like language. The uC's are anywhere from $35 to $90 each; easy to program, but impossible to use for developing something viable for todays' markets.
     
  7. SgtWookie

    Expert

    Jul 17, 2007
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    Interesting! BTW, I know what a PDP 11 is; a project I worked on started off with a PDP 11 and graduated to a VAX 11/780 ;)

    You can do a lot with just 2 channels and 60MHz bandwidth.
    It really depends on what you want to do.
    If you're looking at digital signals, you'll probably want more than 60MHz bandwidth; a 20MHz clock looks mighty "spikey" on a 60MHz scope. Remember that a square wave is the sum of the odd harmonics of the fundamental frequency, so the more bandwith the 'scope has, the better.

    However, 60MHz is adequate for many hobbyist purposes.

    It's an option if you can meet face-to-face with the buyer and examine the equipment before you fork over your dineros.

    If you're buying on an auction site, you'll have to do your own research on the seller, and how well they represent the merchandise they're offering.
     
  8. bill l

    Member

    Oct 11, 2009
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    sgt.,

    i went to the fellow's place to check this scope out after talking to him on the phone.

    verified it worked and proceeded the negotiations which worked in my favor.

    i have not seen a lot of equipment on there, but just about every time something was listed, i was able to get first dibs on.

    bill
     
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