Scientific applications

Scientific applications

This is the most suitable to write blog posts that cover research and scientific instruments. Of course we always talk of accomplishments by Maker, on a budget. Although, in some cases, touching topics of great science, and with good results.

To deepen these topics please consult also the site Physics Open Lab

  1. Marco says:

    I made the basic version (laptop) of your incredible tool (Theremino Spectrometer N.D.R.) and I am going now to realize the BenchTop version. Amazing really! I never thought I'd reach similar accuracy with a webcam and a small piece of DVD!

    I started from the instrument should have quite similar to yours, published and marketed by PublicLab, that actually has good performance, but is less versatile, customizable and that, unfortunately, is also more expensive in the realization.

    Are then “landfall” a colorimeter/photometer produced by IORodeo (USA), simple but nice in conception and realization, with a decent Kit software. Of course the colorimeter is different from the point of view of construction and performance. The IORodeo Colorimeter is a little’ expensive, always thinking in terms of philosophy “Maker”, But however well developed.

    Eventually I got to the Theremino System which I consider to be the best, Thanks to the excellent software. Better both as a system board that as spectrometer. The latter is qualitatively superior to others and has an excellent price/performance ratio.

    I attach two “shots” made with Theremino Spectrometer, This is the resumption of two sources side by side, an IR LED and CFL 925 NM nominal and resuming only IR LEDS.

    The calibration was made initially on two lines of the CFL 436 and 546 NM. In the picture with the two sources you can appreciate the ability to range from UV to IR in one shot!

  2. Dear Blog readers Theremino, I'm a ham radio operator and I write on behalf of the “Radiosismici Precursors” that was set up in our Associazione Radioamatori Italiani (ARI). Handling of course electromagnetic signals monitoring precursors, so-called “radiosismici”, We would be interested to know how we could adopt the system Theremino, aim of this usage. What costs we should estimate? It would also be very interesting to launch an input to the organizers and transmission system, in order to learn about their willingness to cooperate with our group ARI at this early stage of research. A friendly greeting and thanks ! Alfredo Gallerati (IK7JGI/ARI)

  3. Sorry Livio, What is your last name? Thank you !
    Cordial greetings
    Alfredo Gallerati

  4. Marco says:

    Good morning, I wanted to ask, about the DIY spectrophotometer, If using the DVD in reflection instead of transmission( that is, if the piece of DVD can work as reflective pattern) or if there are more problems than advantages. My question is why reflection spectrum seem far more “brilliant” compared to DVD and also to the sheet from 1000 lines/mm

    • Livio says:

      In our tests use patterns in reflection gave worse results. Probably there are some factors that I don't know and I can't explain. If you have doubt proof, Maybe you'll get better results of ours and if so please enter it here.

      A detail that we noticed and which we may not have explained in the documentation is that the lattice is good to keep it at a distance from the camera lens. So it takes a while’ black plastic tube, Maybe 5 or 10 mm taking outdistanced lens pattern. Usually the same lens hood lens should be enough but in some cases it may be useful to add some’ by mm black tube. Even this can't explain the reasons but I have checked several times that improves the graphics.

      It would also be good matting (with sandpaper) all black surfaces that can create reflections. And then also the inner surface of any tube spacer.

  5. Hi Livio, this is amazing work fratello! I was trying very hard to figure out how to install the theremino spectrometer. I was hoping you could help. I’ve tried using the information provided but I cannot figure it out. Was hoping you could help. I will be using your spectrometer software to help people with health issue for free.

    Grazie e ciao,

  6. Michael and Joshua says:

    Hello together,
    my son do a lesson in Physics at school.
    The lesson is, split light into Wavelengths.
    So i say to him, lets try to build a Spectrometer.
    There ist a great Projekt for this Question.
    But we cant get the linked Trust USB Camera´s.
    So my Question is, what ist the best FOV for the Theremino Spectrometer.
    I mean what kind of lense will work.
    A fisheye Lense or a Lense that will act like the human Eye.
    What we found in the WWW.

    – 1.8mm Lens – 170º FOV
    – 2.1mm Lens – 160º FOV
    – 2.5mm Lens – 130º FOV
    – 2.8mm Lens – 115º FOV
    – 3.6mm Lens – 85º FOV
    – 6.0mm Lens – 50º FOV
    – 8.0mm Lens – 40º FOV
    – 12mm Lens – 24º FOV

    Ther so much Web Camera´s availible, we cant make a choose.

    Please give us a hint, which FOV ist the best to build the Theremino-Spectrometer.
    Thank you very much.

    Best Regards from Germany,
    Michael and Joshua

    Ps. Sorry for my unperfect English

    • Livio says:

      Sorry we do not know the FOV of the camera used.
      A normal WebCam with a medium FOV will be OK.
      Maybe you must try many camera to get one good working.
      The problem is not only the FOV but also the driver regulations, and also the infrared filter placed in a position wher you can remove it.

      WebCams are cheap the only method to individuate the best cam is to try some of them.
      Before to individuate the Trust we have tried 4 or 5 cameras.

      • Michael says:

        Hello Livio,
        after a sleepless night,i found this Web-Cam.
        The IR-Filter should be in the lens system.

        Resolution: 2 MP 1920×1080

        Lens: hundert degree FOV
        Supported OS Windows
        Plug and Play UVC compliant

        Controllable Features:
        Brightness, Contrast, Saturation, Hue, Sharpness, Gamma, White balance,
        Backlight contrast, Exposure

        Is this Web-Cam usable for the Spectrometer?

        • Livio says:

          It will work but it is impossible to know how will work without testing it.
          As a principle, do not buy WebCams too much expensive, and maybe try two different cams.

  7. Livio says:

    We moved here the Flicker Meter messages.
    Abbiamo spostato qui i messaggi sul Flicker Meter.

    • etc says:


      Thank you for this simple but effective design with real and practical applications for everyone.
      Having build the FlickerMeter and tested various light sources and globes I can confirm your results and comments. In addition I found that all Dimmable LED globes tested had a high flicker (12-16%) rate even without dimmer while all NonDimmable LEDs had practically zero flicker.

      Interestingly 12V dichroic halogen globes (downlights) had the lowest flicker of the incandescent globes with 1.4 % and zero with DC supply, giving also the best colour rendition and near infrared light important for eye regeneration at night. That to me would be the ideal reading light.

      The screen of a tablet computer showed a flicker of 46%. The Iris eye protection app lowered this value to 21% flicker.
      Then I tested the flicker of an older Toshiba Satellite laptop and it showed no flicker at all, 0.1%.
      How can that be? Is it possible that the flicker frequency is too high to be processed by the meter and software?
      A few times while measuring I wished that the FlickerMeter would also give me also a frequency reading, for example when testing fluorescent lights and CFLs with electronic ballasts o r LEDs with dimmable power supplies
      Thanks again for making this and many other excellent designs freely available!

      Kind regards


      • Livio says:

        The tablet flicker is produced by led retroillumination regulated by a raw PWM signal. This is a poor design, a better method is to drive the LED retroillumination, with a constant-current, switching power supply. The current is trimmed to get different illumination values.

        Many monitors have constant current LED drivers, and so they have zero flickering. My monitors (Samsung SyncMaster 913n – more than ten years old) have zero flickering also if regulated with low luminosity.

        As explained in the instructions, to measure the frequency you could use the Theremino SignalScope and WaveAnalyzer applications. But remember that we can only see low frequencies (about 200 to 300 Hz maximum).

        It is important also to know that all the lamps connected to the 50 or 60 Hz power supply have a flickering frequency of 100 or 120 Hz.

        Only dimmers can have an higher frequency, maybe 250 or 500 Hz and in those cases it will be difficult to measure the frequency, because our system is limited by the USB data exchange time.

        • etc says:

          Thank you, Livio for your explanations. That cleared up a few questions.
          There then still remains a question: How will the FlickerMeter respond and what flicker index value will indicated if the flicker frequency is higher than > 300Hz and perhaps up to the 40 kHz range? Will it still show the correct flicker rate?

          • Livio says:

            At frequencies above 300 Hz there are no more differences between pulsed light and continuous light, neither for humans nor for animals.

            The application Theremino FlickerMeter should give correct values up to many KHz, because it controls all the mimimi and the maximum readings, sampled in a certain time interval. In this way, although the sampling rate is at most 500 … 1000 Hz, there are always some samples representing the minimum value and other samples representing the maximum value.

  8. Giacomo says:

    Hello Livio, I need some help regarding the Geiger. I tried following the instructions on the doc available. I also found that the cable Adapeter-Master (bought on ebay with the Adapter GA500-V3) had the signal and the + 5V reversed. I have a pipe SBM-20 (I checked the polarity when I plugged the adapter). By connecting this worked fine for a few minutes and then started to unload suddenly reading valors. The fact is that read those values even unplugging the cord on the adapter (but leaving it attached to the master. I checked the voltage at the ends of the pipe and mark 236V. Possible? I would expect 400v since I jumpered as instructed (Bridge-gnd marks 400V). What tests can I do?
    Thank you

    • Livio says:

      From what you wrote I can't understand.

      However it is normal that the cable left open (not connected to the adapter) disorders take on AC power and then counts alone.

      And it's also normal that if you measure with a tester you are 200 volts or so.
      Should be measured with a high impedance divider as explained here:

      Write me at engineering at sign theremino dot com
      So then we'll hear over the phone or skype and we fix.

      • Giacomo says:

        Ok, I'm just not sure I can put on short-time probe HV.
        As soon as I can I will send you my skype contact. Thank you

        • Livio says:

          No need to build a probe HV, the voltage is OK, you have to look for other defects.
          It's probably a stupid mistake, Maybe the wrong cable or interrupted, or the jack touches.
          Or maybe the female jack poorly soldered on geiger adapter (look good all welds with sometimes miss the pond).
          Or, but I hope not, is the geiger tube bad, every now and then Captain pipes that discharge time (many ticks per second).
          We can help you should say something more, for example how many ticks per second (I count the application Geiger).

          Do this test:
          1) If dissaldi the geiger tube from GeigerAdapter (and let the GeigerAdapter connected to Master) then stop making tick-tick?
          2) If in these conditions combine the two threads that should go to the geiger tube makes a tick?
          If the two previous tests have gone well (i.e. the first shut up and the second does tick) then it surely the Geiger tube which discharges inside.

          Then make rebuttal:
          1) Verify that the GeigerAdapter without a geiger tube shut
          2) Connect the geiger tube at GeigerAdapter.
          3) If it starts to make tick-tick (more than one per second) then it's defective tube.

          A doubt… the geiger tube you've connected to the two rectangular plots real? I ask this because some have linked the positive of the tubing to the bridge 400 volts, instead of the rectangular pitch at the top.

          If you can't find the fault and I will forward it to quickly without getting Lello spending anything (unless the pipe that cannot be repaired and must be repurchased).

          • Mom says:

            I'll add to the discussion why this past summer I had had some trouble with the geiger adapter.
            I don't know if it can be something like. In my case, After a while’ of evidence (the output voltage was too low) I had traced the cause to excessive humidity in the air.
            I equipped with dehumidifier and humidity digital meter and actually whenever I crossed a certain threshold of moisture (I don't really remember, but I think it was over 80%) I no longer counts.
            Dehumidifying air (couldn't remove just the 10%, maximum 15% given the excessive conditions), After some half an hour everything came back normal: I had the counts and the tension had become more acceptable.
            I also used a SBM20.

            • Livio says:

              In the case of James counts are too many, If I understand correctly true pulse bursts. Probably dozens of pulses per second. So it may not be due to moisture.

              Actually it can happen that a very high humidity “bathrooms” the printed circuit of GeigerAdapter and cause leakage current between components that work with very high impedance (the zener voltage regulating especially).

              A humidity so high, not only can change the regulated voltage, but it can also capture dust particles and merge them into a sticky layer that, the long, could bring the GeigerAdapter to stop working altogether (If clean with great Dielina and brush).

              High humidity can also oxidize copper parts and welds and slowly destroy the circuit beyond repair.

              The solution is not to dehumidify the whole room (too expensive) but closing the Geiger Adapter in a small plastic box and add in one packet of desiccant (Silica Gel).

              To make waterproof box connector can be used, or pass the wires from holes and seal with glue (hot glue or PVA glue).

  9. Giacomo says:

    I'm starting another discussion or is too tight. In response to questions by Livius: I still have the evidence that you told me (as soon as I get rid from some family commitments); I had connected the hose to the correct pitches.
    I summarize briefly the abnormal operation: I connect everything as indicated on documentation, start the program Geiger and HAL starts automatically, imposed HAL, type of pipe, etc.. After a few seconds, begin ticks and for about 5 minutes feel random ticks with measure approximately 100 NS/h in my living room (I sing for joy). Then suddenly the tick becomes frequenstissimi until you have the features of a white noise (Obviously the measure rises to values close to the primordial Big Bang).
    I'm starting to think that the tube is defective.
    Take this opportunity to ask you one more thing: the Geiger brings with it a the HAL 6.1; I can normally supplied with the latest version?
    I tried and the problem repeats the same though!

    • Livio says:

      The software isn't for sure, the only possibility (but don't think it's your case) is that you're using a different application thereminica that writes to the Slot that is used for the geiger (usually the Slot 1 If you don't change it).

      In very rare cases may also happen that the 5 Volt significantly unstable USB (Bad USB), in this case it would be useful to try another PC (or notebook, or tablet).

      However there is a simple test that removes any doubt:
      – Disconnect the geiger tube from geiger-adapter and verify that there are no pulses.
      – Finger touches both the two wires that go to the tube (do not give the shock because they are a few microamps). And make sure that every time you touch them give one or two ticks.
      – Or put in short the wires that go to the pipe and make sure that they do some tick.

      At this point, electronics and software are fine. Then you can make a rebuttal, connect the geiger tube (without changing anything else), and see what happens.

      If the geiger tube is defective you may write the seller and explain what happens. The sellers know that occasionally the pipes make this joke and could e-mail you another quietly. Or you could just buy another one from him and, After you have verified that the second work, send the first and get money back (If you've got on eBay and is not spent too much time reimbursement is assured).

      The HAL you can replace it but nothing changes. The HALs are all okay for simple jobs that need doing here (nothing Adc24, nothing FastPwn, No Encoders, only count pulses).

  10. Giacomo says:

    If you touch the wires with your fingers, click. If I put these in short, starts the Swish that I said and the measured value skyrockets.

    • Livio says:

      If you put them in short can make a flurry at the moment make contact, This is because merging the two metals them lightly against one another. But then, Once the short is stable, should shut up.

      By tapping with your fingers, Depending on how you touch, can do a few pulses or even a small gust.

      The important thing is that shut when open or closed is firmly firmly. If it doesn't do so text me, never happened but everything can be…

  11. Livio says:

    KEN wrote us about spectrometer and asks:
    1) And’ can analyze Spectra from 250 NM at 1100 NM?
    2) On the spectrum produced by the software the X axis is the frequency. If the Y axis cannot be used to measure the intensity so what measures?

    Reply 1:
    The frequency can be measured by 250 NM up to 1200 NM with good accuracy (+/-0.5 NM in excellent condition). But the amplitude (amount of light) cannot be measured.

    Reply 2:
    The X axis is the frequency with good accuracy.
    The y-axis is the intensity, but the precision is so low that it can be used just to see where the peaks.

    If you increase the intensity of the light frequencies saturate in webcam for which relations of intensity between the various frequencies change significantly. If you decrease the light intensity measurements that you make in the valleys are almost noise only.

    The dynamic between the lowest and the highest is hardly anything that you always work with part of the graph in saturation and other parts dominated by noise.

    Also some frequencies (infrared and ultraviolet) are tracked with significantly lower sensitivity. And this changes considerably from a WebCam to another.

    You cannot make an adjustment of the intensity because it would be valid only in the exact conditions under which it was made. As soon as you change the amount of light, the webcam, and its driver, would the answer and would no longer be valid.

    Product intensity errors from all causes totaled exceed dozens of times, and even hundreds on the extremes of the band.

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