Sometimes It’s Not The Solution

Watching a video about a scratch-built ultra-precise switch for metrology last week reminded me that it’s not always the projects that are the most elegant solutions that I enjoy reading about the most. Sometimes I like reading about hackers’ projects more for the description of the problem they’re facing.

A good problem invites you to brainstorm along. In the case of [Marco Reps]’s switches, for instance, they need to be extraordinarily temperature stable, which means being made out of a single type of metal to avoid unintentional thermocouple joints. And ideally, they should be as cheap as possible. Once you see one good solution, you can’t help but think of others – just reading the comments on that article shows you how inspiring a good problem can be. I’m not worried about these issues in any of my work, but it would be cool to have to.

Similarly, this week, I really liked [Michael Prasthofer]’s deep dive into converting a normal camera into a spectrometer. His solutions were all very elegant, but what was most interesting were the various problems he faced along the way. Things that you just wouldn’t expect end up mattering, like diffraction gratings being differently sensitive across the spectrum when light comes in from different angles. You can learn a lot from other people’s problems.

So, hackers everywhere, please share your problems with us! You think that your application is “too niche” to be of general interest? Maybe it’s another example of a problem that’s unique enough to be interesting just on its own. Let’s see what your up against. A cool problem is at least as interesting as a clever solution.

53 thoughts on “Sometimes It’s Not The Solution

  1. “So, hackers everywhere, please share your problems with us!”

    Since I believe that many of Hackaday readers are “age positive” (like me),
    you may end up with long drawn out complaints about arthritis, loose dentures, kids on their lawns, how things were better back in their day…

    B^)

  2. I’ve got a nice problem, although I’m pretty sure i know what the answer is.: My 4 cylinder Kubota hydrostatic powered robot’s GPS works fine for about 1 hours of use and then goes on the blink. This is indicated by a cluster of bright red LEDs bolted onto the top of the robot. Also, after about 1.5 hours of use, it will seemingly randomly lose control and veer off the the RHS. The control panel has 2 fans in it and does not get hot and it makes no difference what the ambient temperature is. The battery is a little bit worn out but the machine starts fine. If I turn the engine off whilst the LED indicates bad GPS, the LED starts to indicate good GPS once more. These are more than enough clues for you lot to successfully diagnose the problem, so get your brain cells into gear and let rip.

    1. Assuming the electronics are powered by the engine’s electrical system and not a separate battery. Can you try running them separate or at least inspect the cleanliness of the engine’s regulator and rectifier? Car electronics are usually very tolerant of transients, off the shelf stuff probably not so much

        1. Starting the mower discharges the battery a bit and the charging system sees a lower impedance till the charge tops off.
          How that relates to electrical noise….?

        2. Noise could be making the GPS or controller leak some resource. Take an hour to run out, (after running the reconnect process long int times).

          Simple test, independent power cycle of GPS with engine and controller running. If that fails to clear the problem, repeat on the controller and GPS.
          Basically: ‘yank and spank’. Power cycle components until you find the one that restores function. There’s your problem. Could be coms between the last two. Double check your grounds.
          It’s _always_ the power supply…Except when it’s ground…
          Look at reconnect/bad packet metrics when failing.
          Don’t count on chassis ground being good. Measure resistance between ground connection points.
          Mind the regulators on the digital devices.
          Beware solenoid noise, put those on their own power, bigish caps, isolators.
          Sensor noise…Cat 5 cable makes for good noise resistance. Ground all pairs not in use. Available for free in the basement of local police stations, just bring clippers.

          If GPS part of controller (e.g. it’s running on a phone), there’s your problem.

          If I had to take a wild ass guess. I’d say look at the mini-gun/40mm controller circuit.

        3. Engine RPMs tend to change as an engine warms up, and if the regulator isn’t up to snuff then maybe it’s letting some of that through as a voltage fluctuation. In particular, if you shut off the engine and the electronics briefly go back to normal (because they are now only on a 12v battery with no alternator spinning) then that might be a clue.

          If you can run it off a second battery not connected to the engine’s juice at all, it is at least a good diagnostic tool—it would tell you where not to look, and cross out a big list of things to check in the future.
          On the other hand, if you run it independently and it’s fine, then it tells you that the problem is somewhere in the power supply. It’s a way to divide and conquer the issue.

          1. Another possibility: The regulator itself gets too hot and starts to drift around an hour into operation. Might be worth swapping it with a spare, those are usually fairly cheap parts.. Also could use a separate regulator for just the control system. Or as I first said, a fully independent battery which would eliminate the most question marks across the system

    2. Maybe electrical noise at the sparkplug wire. Some thermal differential is making a spark gap between spark plug and wire from ignition coil after thermal expansion over that time interval.

      1. I was thinking that too, but a Kubota 4-cyl is usually diesel, so no electric ignition. If it does have plugs, they make plugs with (usually 5 or 10k) resistors inside to arrest broadband EMI. Is the GPS unit near the engine’s ignition system?

    3. Thanks guys. Anyway, I put the whole set of symptoms into CHATGPT and it came out with some good suggestions most of which have already been mentioned here so far, but with one extra one. It’s most likely a combination or one of the following: bad earth, faulty regulator, old regulator technology or unexploded projectile in the 40 mm cannon. The plan is to firstly go through the earth connections, then replace / upgrade the charging system which might include the alternator as well. Not sure if I really want to connect my ‘scope to the regulator output as I think it’s safe to assume it’s the charging / electrical system at fault. There are various solenoids in the system, but they never cause a problem when activated. There’s also DC electric motors, one of which gets warm after a while so if there’s still a fault, it might be worth looking at these.

      1. If you don’t want to risk a scope, a simple voltmeter will do. Measure the voltage at the battery and rev the engine, see if it caps out around 14.5-ish or if it keeps going up into larger, scarier numbers.

        The clue that it recovers when you stop the engine definitely points to that area, but I suppose other things are possible. I assume it’s a diesel, correct?

    4. Can you get to the GPS output data stream? Seeing the satellite Cn0 values and such might be useful. Also, seeing if the GPS is re-booting and not re-acquiring sats could be instructive. GPS receivers can get an initial fix (like maybe before the engine starts) and keep it at lower Cn0 values. Then if it loses that fix or maybe just the sat constellation changes enough to need new sats and the alternator/ignition noise is too severe to acquire the new sats.

    5. I would check alternator diodes, Kubota equipment used to use minimalist tiny (amps as well as physically) alternators often Denso that take a beating on outdoor equipment. Iffy or weakest diode could be heating up after a while, and would still run anything not too picky about ripple. Then grounds etc mentioned elsewhere.. Just a thought!

      1. Yeah, diesel alternators are typically afterthoughts (the motor doesn’t really need it aside from starting). If you are running a bunch of digital stuff that is not auto market electronics, you might want to put a 12v dc-dc buck-boost type thing in line to make sure that the automotive “12v” (in practice anything from 11v to 15v) actually puts out a reliable 12v that, say, electronics that usually run off a wall wart would prefer.

        Is this a home-made robot or something that someone else built?

        1. It’s a modified diesel powered Ransomes Highway 2130 Cylinder Mower. Other than this electrical problem, it works quite well, although does weave slightly between way points. I’m probably going to try running it off an aux battery and assume the grounding is ok. Aerial video demo to follow.

    6. My first thought was that maybe there’s a part that when heated warps just enough to disrupt the function of its RF shielding. On a gas engine something like the ignition coil or spark plug wires. On a diesel maybe an alternator component. Maybe just walk over to it with a cheap handheld gps unit every few minutes with the screen pulled that shows satellite connection and strength info and see if that starts to suffer as you get close to the machine, especially as it’s ran longer. All the other suggestions about checking the grounds and charging system are really good to. In working with weird intermittent issues with old machines I’ve definitely had marginal grounding cause weird issues, which sometimes only showed up when the machine was hot or under load.

      One other thing would be to try to verify that the gps unit can hold a good fix for more than an hour. Maybe there’s some software glitch in it where it has memory issues that accumulate, and for some arcane reason just rebooting it doesn’t clear the buffers or whatever. If there’s a way to hard reset the gps when issues crop up, that might help show if the gps unit is the source of the issues. Or to test the gps separately somehow? Even just let it sit there parked and running for 2 hours and see if it loses its fix or conks out. If there’s some way that you can pull error logs from the gps system that might be helpful.

    7. Also, I’ve had bad experiences with marginal starters, alternators, and batteries all offing each other in term. Put on that new alternator and the marginal battery has almost destroyed it a month later so it can’t keep up with the marginal battery. Replace the battery and the beat up alternator goes out soon after, but not till after damaging the new battery. Full little games like that, lol. If the battery is known to be worn then I personally wouldn’t risk it, I’d replace that at the same time I replaced the alternator.

  3. So, hackers everywhere, please share your problems with us!

    But exactly how or where to share our hacking>harware>repair>etc problems? I have many! it would be nice to have some place to just come and ask for help, because commenting for help in the new incoming hack is not very efficient, they are piled soon and forgotten unless you do an specific search.

      1. I used to have forums full of people of dubious (and perhaps sometimes well-informed) help with my projects. Now I have a simulacra of those forum posts, which may or may not be put together with any kind of logic or reason.

        Everything stays more or less the same, it just gets slightly faker and crummier. Life isn’t significantly different than the end of the 20th century

  4. Either the Hack chat area or the Stack are pretty good places for this. Stuff in the Stack area tends to be longer lasting, while the Hackchat text disappears in hours to days. The Hack Chat area is pretty quiet these days, but a lot of people still pop in and see if there is anything interesting being discussed and then back out if nothing is going on.

        1. oh! I see ,thanks for the info, I have never been there :) I’ll check it out. But I think a good part of Hackaday readers are like me : go to https://hackaday.com, read the daily hacks, maybe comment , leave . So yeah it makes sense what Reluctant Cannibal says, maybe some kind of weekly free for all clinic. I remember back in the days of DTforuM, there where tons of users daily asking and providing help in all kind of electronics topics, it was the place to go if you bumped into an electronic problem, I used to go the Spanish section for schematics, advice and equivalent parts, then they put a paywall and things weren’t the same anymore, people started to move to Facebook groups instead and that was the end of the site. I think I still have a bunch of bin files for TV’s eeproms somewhere.

    1. The Stack is probably ‘supposed’ to be the area to do this, but never seems to be very effective or much used. Those PCB design clinics run by Arya Vodostock (wrong name) on these pages is pretty good IMO so maybe some kind of weekly free for all clinic could work?

      1. I have had kind of mixed luck with the Stack also, but some of the stuff I do is pretty obscure.

        Arya is very kind to be doing the reviews. A good review is a lot of work to do. I did a lot of them at my previous employer. The projects that we did were all over the map, so there was not much commonality between them.

  5. I created a laser scanning microscope from two DVD pickups (https://github.com/NilanEkanayake/LaserScanningMicroscope).

    Problem:
    I use two pickups, one to hold the sample and move on the Y axis, the other that scans the sample and moves over X. The X axis does the fast raster scan while the Y axis moves more slowly. The issue is that the pickup voice coil axis was only designed to hold a tiny lens, and thus the samples can be neither large nor heavy. That means no slides and no locking mechanism apart from super glue to hold the samples. I’m in the market for an alternative. Either a new Y stage that is fast (50mm/s?), sub-micron accurate, cheap as dirt and doesn’t require an exotic drive circuit, or a way to integrate the Y axis into the X axis scan head, either by moving the whole pickup, or some other solution (I’ve had no luck). I know that there was a guy on YouTube who used a linear screw thingy to hold the sample, but it’s nowhere near accurate enough and is slow. I’m considering using a speaker for the Y axis voice coil actuator, or maybe some form of cheap piezoelectric one.

    My goal was to design a compact, simple and super-cheap ($30 for single, $10-15 in bulk) microscope. I did all that, but sadly it’s just not useable without a better sample holder.

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