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Microcontroller lab startup help — Parallax Forums

Microcontroller lab startup help

Invent-O-DocInvent-O-Doc Posts: 768
edited 2012-05-09 15:49 in General Discussion
Hi everyone.

I have the opportunity to set up a microcontroller lab at one of my work sites. We will mainly be prototyping interfaces for medical training systems and building wireless response devices. We will also teach some basic classes on microcontrollers focusing mainly on propeller and a little tiny bit on the stamp. I'm largely trying to replicate the lab I have at home, but have things work well for beginners.

My rules are that it is very difficult to do purchase order (military), so things have to be simplified (kits help). We aren't too cost sensitive (but don't want to be extravagant). Each order has to be under $3,000 to qualify for a credit card purchase. I've selected three sources: Parallax, jameco, and sparkfun. Some items are cheaper at parallax but had to be purchased elsewhere to keep parallax bill under $3K.

As far as you can see, are there any major items I'm missing that you would recommend for inclusion?

I'm worried about forgetting about some huge show stopper because we won't be able to place another order until late Fall. (Spreadsheet attached w/ three tabs, plus text file version)

Thanks in advance!

Comments

  • ElectricAyeElectricAye Posts: 4,561
    edited 2012-05-08 18:57
    Heat gun and heat shrink tubing? I can't live without it.
  • RDL2004RDL2004 Posts: 2,554
    edited 2012-05-08 19:01
    I would not buy that scope. You can do better for less cost or just as good for much less cost.
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-05-08 19:05
    Thomas,

    It looks like a lot of thought went into your selections. I would definitely ditch the obsolete 74LS parts kit, though, in favor of your own selection of 74HC-family parts, which should include basic gates, along with the 74HC165 and 74HC595 shift registers for port expansion. The HC family can run on either +5V or +3.3V, which makes them compatible with the Propeller. I'd also add some high-current drivers, like the ULN2803. 'Maybe some optoisolators, too.

    -Phil
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-05-08 19:10
    'Just took a look at Jameco's linear parts kit. It appears to be missing some useful parts, such as LM358, LM386, LM555 (or, better, TLC555), etc. That and their 74LS kit make me wonder if Jameco is using their parts assortments as a way to unload inventory that doesn't sell. It'd be better to put together your own kit of parts that are more up-to-date.

    -Phil
  • CircuitsoftCircuitsoft Posts: 1,166
    edited 2012-05-08 19:19
    Oscilloscope @ SparkFun

    Bench Supply @ MPJA - We have many of these where I work, and they're highly recommended.

    Soldering Station @ MPJA - We have a few variations on this at work. They're not fantastic, but I don't expect you'll be doing a lot of soldering at such a lab, so it should be fine.

    I would probably ditch both chip kits in favor of a small selection of Op-Amps and a few logic chips people mention here. For the most part, since you're building a "microcontroller" lab, you'll have little need for external logic, apart from the '165 and '595 that PhiPi mentioned.

    The XBee kit from SparkFun is quite a bit cheaper than the one from Parallax, and I don't think you're missing anything in it. You could also buy XBee straight from Digi (Full disclosure: I work for a division of Digi).

    In general, I've been pretty unimpressed by Jameco in the past, and would recommend DigiKey or Mouser where reasonable and SparkFun otherwise. Most of the Equipment you get from SparkFun could be sourced from MPJA to cut down on the SparkFun bill.
  • ElectricAyeElectricAye Posts: 4,561
    edited 2012-05-08 19:56
    IRF3708 mosfet. These can switch a lot of current directly under the control of a Prop. Just nice to have around.
  • RDL2004RDL2004 Posts: 2,554
    edited 2012-05-08 20:16
    Saelig sells the Rigol DS1102E (the 1052E was recently discontinued).

    Rigol manufactures HP/Agilent's lower cost scopes.

    Saelig also has that Lascar power supply.

    Note that some low-cost power supplies are switch-mode, but that probably won't be an issue if you're working mostly with microcontrollers.
  • Invent-O-DocInvent-O-Doc Posts: 768
    edited 2012-05-08 21:03
    Thanks to everyone who posted so far. I'm going to keep it to these three suppliers (every govt purchase order is torture).
    The LS kit ain't sexy but works for me at 3.3 and 5V (not efficient) I may end up ditching that purchase. I like my old one at home but it doesnt get too much use.

    I'll add the 74HC165 and 74HC595 and ULN 2803 like Phil says and whatever is in Matt Gilliland's cookbooks. The linear kit has the LM386 (and a discontinued higher wattage version) & 555/556 though I use a newer philips chip for sound now but jameco doesnt carry it in DIP. The IRF510/3708 mosfet and optoisolators are also good suggestions (I have a similar set up at home and have optos/mosfets + more max232 chips). Oh yes, heat shrink stuff is a great idea I completely forgot about.

    I would consider MPJA for power supplies but won't get any other iron than the Hakko cause Ken G says its the bomb. One better deal doesn't justify adding another source. (I use MPJA when i get their catalog about once a year - good deals especially on power supplies!). I'll switch oscilloscope to the one on sparkfun - thanks!

    Thanks for the suggestions so far, these are thoughtful. I probably wont be able to place another order until December, so thanks so much for the advice.
  • Duane DegnDuane Degn Posts: 10,588
    edited 2012-05-08 22:02
    I haven't looked at your speadsheet but I have a couple of thoughts based on what others have said.

    I know XBees are easy to use but they sure cost a lot. SparkFun carries several different boards with Nordic's nRF24L01+ chip.

    http://www.sparkfun.com/products/691
    http://www.sparkfun.com/products/705
    http://www.sparkfun.com/products/8602

    While SparkFun's boards aren't much less than the price of an XBee, there are a bunch of nRF24L01+ modules on eBay. Some cost less than $2.50. It's hard to pass up ten transceivers for the price of one XBee.

    I believe the little Nordic modules have a faster transmission rate (2Mbps) than XBees have. If you're going to make wireless sensors, I'd suggest taking a look at these Nordic modules.

    The comments about heat-shrink tubing reminds me about what I learned from reading NASA's best practices.
    Shrink tubing installed over components and/or soldered terminations shall be transparent (or translucent) to allow visual inspection.
    NASA-STD-8739.3 [8.1.4]

    After reading the above, I started using clear heat-shrink tubing and I've liked it a lot. It's really nice to be able to see how well a connection is holding together through the tubing.

    I haven't purchased supplies from Jameco, but I wouldn't be surprised if they have clear (or at least translucent) heat-shrink tubing.
  • CircuitsoftCircuitsoft Posts: 1,166
    edited 2012-05-09 10:08
    The XBees do Mesh routing, though, while Nordic doesn't. For your case, I don't think you care. XBee can also be connection-oriented.

    The cheap power supply I linked to is a linear supply; I know because I've opened them.

    For audio amplification, a TDA1517P is a nice cheap option, as is a TEA2025, TDA2611, TDA7056.
  • CircuitsoftCircuitsoft Posts: 1,166
    edited 2012-05-09 10:10
    The MPJA soldering irons are Hakko clones. I have a Hakko at home and I love it, but the MPJA iron isn't bad, until it wears out, though that will be a lot faster than the Hakko.
  • Invent-O-DocInvent-O-Doc Posts: 768
    edited 2012-05-09 12:47
    Thanks to all of you for your advice. I've implemented much of it and appreciate the reality check!
  • mindrobotsmindrobots Posts: 6,506
    edited 2012-05-09 12:59
    This is a use of our tax dollars I actually approve of! :thumb:
    April 15, 2013
    
    Dear IRS:
    
    In recognition of my constitutional rights to "bear arms in a well regulated militia", I will be applying all withheld 2012 Federal Income taxes to the stocking of a home training facility 
    to train me as a citizen soldier in support of Invent-O-Doc Microcontroller Lab. Should I be called upon in a time of national need, I believe I should be properly trained and equipped to 
    answer the call to duty. I will also be contacting the State of Ohio to begin discussions of forming a militia dedicated to electronics training.
    
    Thank you for your understanding in this patriotic undertaking. Detailed invoices are attached to my 2012 Federal Income Tax returns to support these claims.
    
    Sincerely,
    
    
  • Invent-O-DocInvent-O-Doc Posts: 768
    edited 2012-05-09 13:00
    I really love the XBees. I've been using them for years and like the variety of modes, reliable operation, mesh if I needed (which I never do) and also the fact that Digi has such awesome customer service.
  • RDL2004RDL2004 Posts: 2,554
    edited 2012-05-09 13:16
    The cheap power supply I linked to is a linear supply; I know because I've opened them.

    I'm not trying to be a jerk or anything, but the power supply you linked to is quite obviously a switching unit, seeing how it says so on the front panel and in the specifications. Perhaps you linked to the wrong item?
  • jmgjmg Posts: 15,184
    edited 2012-05-09 14:28
    RDL2004 wrote: »
    Saelig sells the Rigol DS1102E (the 1052E was recently discontinued).

    That's ok, but for just some $30 more, you can jump to a 8" screen, and 1Gs/s ?

    http://www.saelig.com/PSBE100/PSBE100008.htm

    For a class, that bigger screen will be important. (and I see they mention a VGA output choice too... )
  • Phil Pilgrim (PhiPi)Phil Pilgrim (PhiPi) Posts: 23,514
    edited 2012-05-09 14:55
    The VGA output would be nice when coupled with a projector for lecture purposes.

    -Phil
  • CircuitsoftCircuitsoft Posts: 1,166
    edited 2012-05-09 15:49
    RDL2004 wrote: »
    I'm not trying to be a jerk or anything, but the power supply you linked to is quite obviously a switching unit, seeing how it says so on the front panel and in the specifications. Perhaps you linked to the wrong item?
    Oops, I linked to the 0-30V one. The 0-18V one (also 0-3A) that's the same price is linear.
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