Hardware Hacker’s Marie Kondo: How Many LM386s Is Too Many?

We’re running a contest on Making Tech at Home: building projects out of whatever you’ve got around the house. As a hacker who’s never had a lab outside of my apartment, house, or hackerspace, I had to laugh at the premise. Where the heck else would I hack?

The idea is that you’re constrained to whatever parts you’ve got on hand. But at the risk of sounding like Scrooge McDuck sitting on a mountain of toilet paper, I’ve got literally hundreds of potentiometers in my closet, a couple IMUs, more microcontrollers than you can shake a stick at, and 500 ml of etching solution waiting for me in the bathroom. Switches, motors, timing belts, nichrome wire…maybe I should put in an order for another kilogram of 3D printer filament. In short, unless it’s a specialty part or an eBay module, I’m basically set.

But apparently not everyone is so well endowed. I’ve heard rumors of people who purchase all of the parts for a particular project. That ain’t me. The guru of household minimalism asks us to weigh each object in our possession and ask “does it spark joy?”. And the answer, when I pull out the needed 3.3 V low-dropout regulator and get the project built now instead of three days from now, is “yes”.

And I’m not even a hoarder. (I keep telling myself.) The rule that keeps me on this side of sanity: I have a box for each type of part, and they are essentially fixed. When no more motors fit in the motor box, no more motors are ordered, no matter how sexy, until some project uses enough of them to free up space. It’s worked for the last 20 years, long before any of us had even heard of Marie Kondo.

So if you also sit atop a heap of VFD displays like Smaug under the Lonely Mountain, we want to see what you can do. If you do win, Digi-Key is sending you a $500 goodie box to replenish your stash. But even if you don’t win, you’ve freed up space in the “Robot Stuff” box. That’s like winning, and you deserve some new servos. Keep on hacking!

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53 thoughts on “Hardware Hacker’s Marie Kondo: How Many LM386s Is Too Many?

  1. I scored several thousand cmos chips (mostly all 4000 series) a few years ago. That’s two Rubbermaid tubs full! I have two more tubs of passives, pots, switches, etc. My ‘workbench’ is contained in a front-opening road case and contains all my electronics tools.
    If I didn’t live in a 350 sq.ft. studio apartment I’m sure I’d have more.

    1. … and that divider can store a surprisingly large number. There have been around 2^34 years since Big Bang and there is close to 2^25 seconds pr. year. That is the first 59 FFs spend. A reasonably fast CPU clocks at 4GHz, which is around 2^32Hz. Meaning – if we started a fast counter (by todays standard) at BB we wouldn’t even have reached the 92nd FF, yet. With only 39908 FFs to go. I think It is same to assume that this counter would last our lifetime – by any definition of “our”.

    2. A D flip flop is essentially a divide-by-2 logic, therefore one can wire them so that every time a pushbutton on the input is pressed, the logic level changes at the divider output. Useful to turn a button into a switch. Some debouncing circuitry (RC) required, or they will go crazy.
      If they are of the CMOS type, eg. CD4013, rather than TTL, their input sensitivity is so high that the pushbuttons can be swapped by touch contacts. They however will need ESD protection, since static charges can destoy them pretty quickly (been there done that:).

    1. The older style embossed labels in my stash have developed a permanent curl, so, they often pop off after I apply them. Painter’s tape sounds like a good idea.

      1. mmm i have that experience with, especially that blue and purple kind of painters tape. Also marker seems to fade real quick on painters tape some how (quicker than on sa, antistatic bag). But maybe thats just more the exposure to sunlight.

      2. I started doing that after someone did it in our hackerspace.

        It makes label changing easy, and if you pick a distinct color, it makes the label part pop out visually.

        I don’t think I’ve moved labels around for a decade, but I could!

    1. Pssshhhttt… Can’t even make 42 NKRO full-size (108 key) mechanical keyboards with 4500 diodes, but Warren G called from 1996 and wants those Regulators back :)

    1. I think I must have subconsciously drawn the line at 1950, don’t THINK I’ve got anything older than that. And that’s only really represented by a few wax paper capacitors, some wirewound resistances and a handful of old germanium parts.

      1. No, No, NO!
        We are using EME wspr/wsjt .
        Now get out there with your giant yaggi or dish, we have a world to communicate with and a moon that is a great communications satellite.
        You(and I) can use the LoRa proprietary(but great) crap for our local area supply network.

        1. I’m always amazed with all the times we went to the moon that nobody ever thought about putting a corner reflector or solar powered transponder up there. Just a simple corner reflector would improve the link budget by about 10 dB or more which would make EME a heck of a lot easier.

          1. A corner reflector is just going to reflect the signal back to where it came from. That’s how corner reflectors work.
            So if you want to talk to yourself over moon bounce, you’re in luck! I think they did put one up, but it’s optical. They’ve used it to measure the distance to the moon very precisely.

          2. Isn’t there a laser reflector up thete?

            There was Project Moonray tgat was about putting a ham band repeater on the moin, I think nuclear powered. It was intended to fit under the seat of the lunar rover. One selling point wastyat it coukd provide backup communucation for the astronauts.

            There were articles about it, bit it was never clear to me how much of it was wishful thinking and how much was concrete.

            The main guy behind it died, leaving things in disarray. And of course the flights to the moon were cut short, and it was one of the eliminated ones that were the target of tye pronect.

  2. I’ve been a collector of fine electronic parts & mechanical assemblies for close to 55 years. 2 semi trailers one double wide mobile home and several small sheds. Lots of neat stuff I may never use but lots of stuff I will and do use. Just hard to keep track of it all. Forgot to mention the garage and crawl space.

        1. So if it’s in a pile it’s hording. If you have labels on it, it’s inventory. A fine distinction I make every day about my inventory to people that want to do a hording intervention :)

          1. Totally correct. Me too. On the other hand if it is catalogued and priced on the website with PayPal payment integration you may have a small business that qualifies for the government payroll protection plan.

    1. Wow! Do future hobbyists a favor and have a plan for that stuff when you check out. In the mid 80’s I watched my dad haul a dead HAM’s entire haul of parts, radios, equipment and antennae to the dump because he was too dumb to see the value and too lazy to find out. Now that I know a bit about electronics I mourn that loss.

      1. Donate it to your local school. My class has a couple of nice multimeters, assorted solar cells and other goodies thanks to deceased hams. Sure, we still had to throw a bunch of it away, but at least some of that stuff has had a second life.

  3. Where’s the credit for the derezzed Norman Rockwell-ish graphic?
    Where’s the craft of using that nicrome to cut a CRT housing into the exact cut-fit needed for Lo-Ra: Princess of Slack (without WebKit.)
    Are there really enough low-hanging energy harvesting things that teaming up enough LM386 to railgun vermin out of the attic or Voltron together a carrot slider prep station in the mudroom?
    This is a slightly weird contest! Thanks!

    1. Art is by our own Joe Kim, and is the launch art for the contest. I though he really hit this one out of the park, honestly, and re-used it for this piece. I just really like it. :)

      The kid with a TV head and oven mitts… It’s like Joe is in my house!

  4. This sounds like how elon musk started making his cars. He has 27000 old notebook batteries kicking around….

    I have barns full of stuff. I am not our typical hoarder though, as if someone can use something and I am not attached to it they can haul it out with my blessings. I have a friend who literally has 13 buildings full of stuff, and if he finds a deal on something he will buy all of them. Things go in and do not go out. I am friends with him but I have a different outlook. I like to see things used.

    A while back I had so many desktop PC’s that if HF still honored the occasional 25% off coupon on spot welders (as an aside, what is it with them making the coupons less and less useful, and the free ones are down to just a damn flashlight.) I was pondering spot welding the damn things together and making an igloo out of them.

    1. I was under the impression Musk bought Tesla. Pretty sure he didn’t build the company’s first electric car in his garage with laptop batteries. Unless you have sources?

  5. I grabbed several hundred ATMega48pb from reputable source when they were on clearance sale for almost 50 cents a piece which was more than half off the regular price at the time. I’ve used up about half since then.

  6. I’ve been good at amassing a great assortment of parts, but my biggest is 2500+ 2n2222 transistors (two full bags, and another mostly full) that were in the recycle pile (!) of the place I worked at the time. (They never actually used that part, and it expired out of the supply bins or something.) I’ve been looking for projects to use them with, maybe synthesizer modules, but it seems that most such analog applications also need the complementary PNP. I’m sure I’ll come up with something.

    1. You can get what, 30 Volts across each, so just cascade all 2500 of them so you can switch 75,000 Volts at half an amp, then you’re set to make a half decent mad scientist beam weapon.

      1. gotta be careful. it’s just like rectifier stacks in the big broadcast boxes. you need to put a resistor in parallel with each the transistors to compensate for the leakage current of each transistor otherwise the transistor with the least leakage will get the full voltage.
        also I’d recommend eye protection. those transistor housings go surprisingly far when they explode. hmmmm.. strike that. maybe a welding helmet would be better. it will be interest to see the base biasing scheme. might recommend something based on a photo relay you can activate with a flashlight through a window from another building. also good idea to have a cellphone ready for 911 call. interesting project though.

        1. and TIP33 and TIP 34s are also my bulk *inventorying* faves. if you have 2500 of each of these you may actually have 2 with the same gain. 🤔
          these parts are really pretty primitive, but I love it. you can build all sorts of stuff with these things. just be sure to design near the low end of the Hfe specification range and thermally compensate all power parts with diodes. also just like 2N3055s the TIP devices gain goes way down at high current.

  7. I am sure there are some amazing collections. It almost screams a global inventory and pooling of resources. Some people who have a truckload of something might be happy to see some gone, others might want to barter or even swap some coin.

  8. Mt favourite goto chip for digital prototyping is some xilinx xc9536xl as I have hundreds of them.

    I put several on a board with the main chips like SRAM FLASH and a microcontroller as a replaceable plugin. I use an extra one to go to an io header. I have many pins just from on cpld to the others.

    Trace routing is done in the cplds rather than complex trace routs on the PCB so its easy to use single sided that I can design and etch in a hour or two.

    It’s like a virtual breadboard routed in vhdl.

    Many times I have been able to reuse a board for a completely different project. Just change the io wiring from the io header.

  9. For my part I’ve got several containers full of TTL and a few specialized CMOS logic. Also a big bundle of assorted processors. I used to have more, but I was forced to clean up…….. And the majority of those TTL parts date back to about the time TI started making them.

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