It’s been referred to as the “holy grail” of teledildonics, and in my hubris, I want to have a go at detecting male ejaculation. Why ejaculation? Well, this is specifically for uses where someone is playing with a male masturbator toy and they climax. Wouldn’t it be great if they got some kind of feedback for their effort? Maybe the game gives them a reward or the content changes somewhat. Without detecting their climax, there’s no way for the system to do so.
Such a detector would need to be:
- Affordable (let’s say, less than $50 per sensor)
- Safe (don’t want to give them a nasty shock or chemical burn as they cum)
- No false negatives (would be disappointing even if it failed to work just once)
- No false positives for other common fluids (lube, urine, pre-cum, saliva, water and sweat)
- Nearly immediate – no point in recognising cum some minutes after the event!
- Robust against environmental factors (like humidity or what they had for dinner)
I set about researching a number of techniques which I thought would bear fruit:
Florescence: The first thought one might have is to do what they do in the movies and use “black light” or UV. From reading this post on the florescence of semen, it turns out that you need Luminol to trigger semen’s fluorescence with UV, though it sill fluoresce under blue light. Besides all that, these fluorescence based tests only appear to work on dry semen, not liquid semen. This fails the “immediate” test.
pH: At between 7 and 8 on the pH scale, semen is slightly basic, but not enough that using a pH sensor is going to give you a distinguishing marker verus, say, tap water. Also, this pH would probably can vary from person to person. Finally, the pH sensors I have seen are rather bulky.
Spectral Analysis: From semen’s spectral response it looks like the 1650 cm-1 wave number range is good for detecting cum. Detection works this way because certain organic compounds in semen vibrate at a certain frequency. These compounds are found in many other organic samples. The problem with this approach is, this frequency is in the mid-range IR, which is very expensive to produce and detect since it’s so close to heat. It would require expensive specialised apparatus to do it this way and it would most likely both destroy the sample and possibly burn your penis in the process.
Resistance: I tried measuring the resistance of cum using various approaches, but just when I thought I understood how it related to other fluids, I got different readings. Besides which, urine (at approximately 70k ohms) is quite a good conductor compared to cum (about 700k ohms).
Electro-chemical: After reading this paper about detecting chemicals. It made sense to me that whatever technique is used to detect glucose in blood or specific ions in solution should be able to work with cum, because I knew cum contained some salts, in particular sodium and potassium ions (see Biochemistry of semen and the Wikipedia page for semen). We were finally getting somewhere!
Voltammetry: A technique known as Voltammetry, passes a known voltage through a sample and observes how the current through the sample changes over time. This recognises the fact that the act of passing a current through a solution will perform some kind of electrolysis on the solution.
Finally, the phenomenon where semen’s resistance changed over time made sense! You see, whenever you pass a current (no matter how small) through a sample such as semen, you are going to change its chemical composition somewhat. We can measure that change by measuring a change in current.
Next, I actually implement a voltammetric apparatus for detecting cum.