Oscilloscope Clock Made Possible By Dumpster Diving

We see people driving around the night before trash collection and reclaiming items doomed to the land fill (or on their way to recycling… who knows). We’re beginning to think we need to join those ranks. Case in point is this vintage oscilloscope which [Bob Alexander] plucked from the curb in the nick of time. Here’s the kicker, when he got it home he found it still worked! He couldn’t let this opportunity go to waste, so he figured out how to turn it into a clock without losing the ability to use it as a scope.

You probably already know that it’s possible to display your own graphics on an oscilloscope. In fact, you can buy a board from Sparkfun which will turn the scope into an analog clock, and that’s exactly what [Bob] did. But he was met with two problems, the X-axis was flipped and he didn’t have an easy way to power the board.

He struggled with the voltage supply, frying his first attempt at boosting the internal 6.3V supply to use with a linear 5V regulator. His second attempt worked though, soldering a 12V regulator to the transformer. He was then on to the X-axis correction, using a rail-to-rail op-amp to invert the signal. The project finishes by adding toggle controls and buttons on the back of the case to switch between scope and clock modes, and to set the time.

17 thoughts on “Oscilloscope Clock Made Possible By Dumpster Diving

    1. Long, but a point at the end. Who throws out functional scopes? First thought that comes to mind is the surviving family of the owner who don’t know what it is, or how to find those who would make use of it for free or a nominal purchase price. This IS “crap” that an auctioneer or some one handling an estate sale isn’t going to bother with because it’s unlikely to bring much much money to the family,and commission to agent. The second reality is lifestyle downsizing brought on my age, disability, reduced income or any combination thereof. Sometimes one can’t find anyone willing to take it when it needs to be disposed of, and it’s impractical to rent storage for items that nay stay in storage until the day you die. Personally I’m facing the second example at this time. As a middle age person who has already outlived many of my age group I grew up with my family could face the first example any time. the point of all this is, if you hope for your “goodies” to to help out others later, plan now to make it happen

      1. @N0LKK makes a good point. I’ve got a collection of cameras, computers, salvaged parts, and (gulp) functioning calculators that are usable and of value to *me*. But, if I suddenly stepped off, given my family’s previous habits, most of that would hit the trash (or e-cycling, at best) out of convenience… unless I’d gone to the trouble to document how to parcel them out to interested parties.

      2. At this point I have to mention Freecycle, a public mailing list that aims to redirect useful but unwanted items from the rubbish heap to a new owner.

        I’m giving away tons of stuff this way, everything from old calculators to sofas, and the average time between post and response is five minutes.

        Makes people happy, relieves me of schlepping the stuff anywere, and is way faster than bothering eBay with a $2 used item.

      3. @NLKK
        That reminds me of one of the saddest days I’ve known. There was an electronics surplus store here in OKC (where anything but a radioshack is nonexistent). This guy had everything from bulk caps and resistors to knobs, pots, stepper motors and even Tubes still in boxes. He bought a lot of surplus electronics from the military and who knows where else.

        I went in one day and he didn’t look well at all. He said he had liver cancer. I went back a couple months later and the place was closed down. I saw the guy that own the shop next door and inquired about it. He said that Dale had passed away and his wife had the whole contents of the store hauled off to the trash dump.

    2. Gak! Accidentally reported your comment when I meant to hit Reply!

      Onto the main point: This Heathkit may be as functional as the day it was made, but, if you look closely, it doesn’t have any trigger controls! That means you have to tune the vernier frequency control to get the trace frozen (more like, very slowly sliding sideways) on the screen. In this age when you can buy a new 100MHz DSO for a few hundred bucks, the value of a triggerless tube ‘scope that has only fixed DC input coupling is marginal at best.

      Certainly one can find some uses for such a beast: as a clock, a tool for learning how vacuum tube circuits worked (as an example of a working circuit), a room heater, and probably more. But “diagnostic tool” would not be high on that list.

  1. Ah yes oscilloscope in the trash. Reminds me of the HP180A oscilloscope I found in a recycle bin covered in snow, knocked most of it off and let it sit open for a few weeks and it works as well.

    by open i mean i took the removable modules out, this one had the 1801A dual channel vertical 50Mhz amp and 1820B time base modules in it still.

  2. In the event the plan is to operate the clock 24/7, wouldn’t a screen saver be warranted? Then again 24/7 operation may be likely to be noticeable on the power bill, and 24/7 operation curtailed. Then when someone will asks Bob what time it is, Bob will have to reply wait until the tubes warm up, and I can tell you. :) Put me on that list of those who never find clean operable gear,vintage or not, destined for the landfill that I can rescue.

    1. N0LKK, according to the scope’s manual, it uses 40 watts. That’s a lot for a clock, but it’s “only” about $60/year.

      Still, I don’t plan to run it non-stop. I’ll probably only use it for special occasions (like making my geek friends jealous :-) )

      – Bob

  3. curb-shopped stuff that does not have an obvious defect works perfectly more often than not.

    People are stupid^H^H^H^H throw away stuff for a variantly of odd reasons, not just because it’s broken.

    I’ve pulled an engine stand out of the dumpster at a self-storage place, where someone probably paid monthly to store the thing.

    I’ve also gone to a yard sale, and not bought antique paper-hulled shotgun shells, then later that evening pulled the very same live ammo out of the closest available dumpster.

    1. For some reason just finding live ammo in a bin like that really worries me, isn’t there laws about disposing of stuff like that? I’m only saying this cause im from the UK were most firearm related stuff is controlled rigorously haha.

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