Friday, April 30, 2010

Chapter 5 - Shopping List Update

Got a few more items in for Chapter 5 from various sources.

First, I purchased 10 germanium diodes and a single piezoelectric earphone from SciToys as the author recommended. Since I was paying for shipping, I ordered 10 diodes instead of just 1... I may never use them but they're not that expensive and I know a few people (including my dad) who are working through the book and I may part with a couple.

I couldn't believe I couldn't find these items locally - no Radio Shack that I called carried either the germanium diodes or the earphone and the few electronics shops I called carried the earphone but it was $10.00 and no germanium diodes.

Note: These items are NOT included in the Components Pack 2 - as a matter of fact, I'm finding quite a few things in the final experiments in Chapter 5 that are not included with Pack 2. (This isn't an error - Pack 2 states it is specifically for Chapters 3 and 4.) I'm trying to capture all the specialty items required for Chapter 5 and will see about making one final Chapter 5 shopping list that contains those items NOT found in Pack 1 or Pack 2. For example, Experiment 28 recommends a 4700 microfarad capacitor but the shopping list specifies 2000 microfarad minimum... if you're like me, you probably don't have any of these in your possession. Again, I'll try and go through Chapter 5 when done and pull together a complete list of specialty items.

Also, I picked up a plastic box for $1.50 at The Container Store... I was in the neighborhood and remembered that I needed one for Experiment 29.

From SciToys (
10DIODES $7.86

(Those are the actual part numbers above with the prices.)


  1. As far as the earphone and germanium diodes are concerned, they actually *can* be found at Radio Shack. You have to think outside the box (or inside the box, as it were). This kid's science experiment kit contains both items and is available in-store:

    So, if you're desperate to do experiment 28 TODAY (I was), this kit will get you there. The down-side: It costs $20 (Northeast US). The upside: The kit also includes other useful items, such as magnet wire, magnets, and a small motor.

    I've also picked up "Practical Electronics For Inventors". Seems like a great resource. However, in reading through the second chapter, I realized that I've forgotten every bit of calculus that I ever learned! Looks like I'll be digging out my old math textbooks...

  2. Joseph,

    I did see that kit but I wasn't certain whether the earphone was the correct kind for this experiment... should have guessed it would work based on the experiments in the box.

    Glad you were able to pick one up and provide the recommendation to others.

    If I can ask - what results did you get from Experiment 28 after you hooked up the 2200+ microfarad capacitor? Same results as with the 220 ohm resistor? Just asking because it sounds like you're running parallel with me on the experiments.

  3. I've kind of fizzled on chapter 5 - I read through the entire chapter, and acquired all the components needed, but I haven't done any of the experiments yet. Got off on a tangent based on chapter 4; I found a copy of the "TTL Cookbook" last week, and I've had my head buried in that. Sourced the components to build a battery powered TTL clock. Once that's done, I'm planning to circle back and complete the experiments in chapter 5.

  4. I totally understand - yes, Chapter 5 has opened with some audio experiments which really don't interest me much, but I'm still wanting to complete them. I'm much more interested in robots, stepper motors, and IC circuit design and programming, so I'm looking forward to the last few experiments, but I must get through the next few first.

    As the author states early in ch5, there are so many areas to explore and chapter 5 has a wide range of topics.

  5. TTL Cookbook is still good (I still use my copy) but don't forget that you can substitute the newer CMOS chips in the HC series which are much easier to find these days, may be cheaper, and require only a fraction of the power. The part numbers and pinouts are interchangeable with the old 7400 chips. It's inadvisable to mix the two families in one circuit, though.

    I used 74LS00 chips for the electronic dice circuit in the book, only because a particular counter seemed appropriate.

    Subsequently I rebuilt the dice (for demo at the Maker Faire) using a single PICAXE 18X microcontroller to do absolutely everything associated with managing two dice displays. If you go all the way to the end of the book, this would be an interesting exercise to pursue on your own. Microcontrollers really do make everything simpler by making it more complicated (complicated because you have to write software and debug it, in addition to the usual soldering tasks).

  6. Charles Platt! I'm star-struck! Right now, I'm looking to source a 7400 "starter kit". Jameco has two; one in 7400 series, and one in 74LS00 series. I was going to go for the LS series. Seems like there's a much greater variety in that kit (450 LS pieces as opposed to ~350 pieces in the non-LS kit). Also, all the TTL clocks that I've seen use LS chips. Plus, my clock will be battery powered - using a Xtal for the time base - so the LS' low power requirements really help.

    James, don't get me wrong, I think chapter 5 is the best in the book for one reason: it's a jumping-off point for so many other aspects of the hobby. At some point, I want to go further down the radio receiver and robot paths. Given that I'm a software developer by day though, micro-controllers (read programming) are kind of what I'm trying to get away from! :-)

    Mr. Platt, I would like to thank you for being the first person ever to explain an LC circuit and resonance so that I actually understood it.

  7. Joe, I'm glad my text was comprehensible!

    One of the great pleasures of writing a book is that it forces the writer to educate himself. I never knew what resonance was all about, either, till I reached the point where I had to explain it. And one of the great advantages of starting from a position of ignorance is that I can put myself in the position of a reader who starts from a similar state.

    Regarding the Jameco offer: That's really interesting. I guess they have bought up stock from a supplier that finds insufficient demand for individual chips and unloaded a heap of them.

    There is absolutely no advantage, in any application I can think of, associated with using old original 7400 series chips. The LS type (which I think dates back to the late 1970s) uses less power, as its abbreviation implies--although still using a lot MORE power than modern CMOS equivalents such as the 74HC00 chips. So, you don't really want to put too many of those LS chips in battery-powered devices.

    Microcontrollers are both wonderful and a pain in the ass. They are wonderfully versatile, but consider that you are writing code to control a device that has no screen (unless you add one) and offers no error messages (for stack overflow, for instance). The PICAXE chips are very cheap and easy to learn, but are especially primitive in some respects. No more than four levels of subroutines, on some of the chips. And just a handful of variables, with byte variables sharing the same memory locations as word variables. And no negative numbers or floating points!

    No doubt the Arduino is a different world, but that would require you to learn their peculiar version of C. I decided not to do that.

  8. CCSVI Clinic Receives Joint IRB Approval for Aftercare Protocol Study.
    Dr. Don Simonson, the Principal Investigator for the study agrees; “Of course there are other reasons that patients restenose, depending on the condition of their veins in the first place, and operator inexperience, so we have designed a study that isolates the aftercare protocol because we feel it may be at least as important, and in any case well worth studying.”
    CCSVI Clinic is already sponsoring patients for this protocol with a 10-day stay in the hospital where patients will be imaged daily, post procedure. If there is evidence of re-occlusion, they will be taken back to the OR and re-treated. To comply with the IRB approval, once home, patients will be examined and/or surveyed at regular intervals by a Principle Investigator (PI) for several years after the treatment to study the changes. Patients will have regular consults with the surgeon who performed their procedure as part of the protocol.
    More and more MS patients are reporting initial success (including vascular and some neurological differences) as a result of the venous angioplasty (liberation therapy) but then regression to previous symptoms sometimes within weeks post-procedure. It is estimated that the failure rate of the “liberation therapy” may be 50% or higher, even through the most experienced and best-known surgeons. Consequently, there is increasing concern amongst patients that the liberation therapy hypothesis needs to include a post-procedure protocol that is more refined than simply releasing the patient from the hospital or clinic within hours or a day of the procedure. If the study hypothesis is correct, it means that there are many other considerations that indicate a post-procedure stabilization period, re-examination, and re-treatment if necessary.Please log on to for more information.