Non-Contact Laser (Photo) Digital Tachometer Review/Demo/Tips DT-2234C+

[@a3rv803]

Thanks for the video bro, any one who actually knows a little how that thing works will understand what you mean with ''divide it by two'' :)

[@mlminto]

just bought one, got it today; works great! we'll see about longevity!

[@stelic9515]

Thanks I like alot how you show us to save reflective tape.

[@felixf5211]

I have this tach. Got it on ebay for around $10. Thought this was a good video. Not sure as to the dislikes. Maybe the last part was a bit too intense for some; not used to brain cells moving.

[@7byseven]

Good review thanks. Be cool to see how to holds up against an expensive one.

[@TheFlamingPiano]

That's a fascinating tool. It's the same thing used to identify speeders in highways right?

[@thetinkeringjuggernaut8538]

Similar idea but they work differently 👍

[@CookieTube]

They both measure a _'kind of speed'_ . That is really the only thing they have in common. But other than that, they are completely different things in every aspect. Note that although, at first sight they also do the measurement based on _'reflections'_ and as such you can call that a similar idea, a reflection isn't even always needed in case of this optical tachometer tool (eg: spark plug)!! So, personally, I wouldn't call that a similarity either. But I understand where you come from. Allow me to explain in detail: This tool measures *rotational speed* which is *number of rotations per time* . The highway patrol thing measure *linear speed* which is *distance per time* . Those two are COMPLETELY different kind of things and have nothing in common, except that both are types of what we call _speeds_ ! RPMs says absolutely nothing about distance. Hence why it also doesn't matter _where_ you actually measure it on a rotating disc or a blade for example. You can measure it on the side, just slightly off center, at almost the outer circumference, or anything in between. It will read all the same RPM. This tool uses a dead cheap steady/constant *light* source, a cheap laser pointer. The highway patrol thing uses *radio* waves in case of RADAR (the more modern LIDAR devices use a light source too though). This tool is used on a *stationary object* . NOTE: the rotating aspect is just a means to have something constantly going 'on' and 'off': a reflection of light in most cases. However, a rotation/movement is sometimes even not needed. Point the tool to a spark plug (which obviously doesn't rotate). Yet, we then know the motor's RPM because we know the spark plug sparks one time per rotation. The highway patrol measures a *moving object* (the vehicle). This tool uses the laser as a source for detecting reflected light *pulses* (aka: on/off). It does this by measuring the time between such received pulses. eg: If the time between received pulses is 15 seconds, it means 4 rotations per minute (=60 seconds / 15 pulses)... That is literally all to it, it is essentially a *dumb pulse counter* . The highway patrol thing uses expensive radar/lidar and the *Doppler effect* to derive the measured speed of the *moving* vehicle. It does this by measuring how quickly the period/frequency of a reflected radar/lidar beam increases or decreases over time, compared to the intrinsic period/frequency of that very specific radio/light beam. This uses highly calibrated high tech equipment and depends on the speed of light. The laser in this tool does double duty as both the source of the reflected light and as an aiming aid. But, as long as 'some light source' gets reflected back into the sensor, you don't actually need the laser at all. You can use an external light source. It essentially doesn't matter what light source it is either, as long as it gets reflected back into the sensor of the tool from the point you're targeting (and there is a clear sharp distinction between on and off for the sensor to detect of course). Or you can even use the measured object itself as the light source, without the need of any reflection. For example the spark plug which gives off light on its own. There are no visible laser beams being used in a highway patrol thing, because of driver eye safety. Nevertheless, a narrow beamed light source is used in cases of LIDAR, instead of a wide beamed radio wave like with RADAR. But in that case, the LIDAR uses a safe invisible infrared laser. Either way, in both cases, that radio/light source is extremely essential for the measurement and as such is highly calibrated and very specific. It can not use an external source of radio/light. (benefit of LIDAR over RADAR is that with LIDAR you can pinpoint and aim at a specific vehicle without having other vehicles around it skewing the reflected signal. RADAR is just a wide broad radio wave and as such can't single out a specific vehicle in a bunch. So it is useless when a whole bunch of vehicles travel together at different speeds) PS: *do not leave your batteries in this specific model!* It has a known design flaw such that it will short out, drain the batteries, and bricks the device if you're not careful enough with it. Newer versions _might_ have fixed that, but even then you never know what version you'll get. And reading recent review comments on this model, it seems it still might have that major flaw (which is a certain tiny ceramic SMD capacitor that breaks and shorts out when bumped/vibrated too much). ---- I know, very old video. But just only now came across it with old comments to reply to... what can go wrong? LOL....... Saw this comment and couldn't help myself because it irks me quite a lot that even on newer videos, and even if the uploaders clearly explained it in the videos (it measures light pulses, that's it, nothing else), people get this wrong all the time, including the massive difference between RPM and linear speed.

[@TheFlamingPiano]

@@CookieTube I was really just here to give support and engagement to his video, back when we were trying to grow our channels. I actually have no idea what anything is and honestly just spaced out most of the video. We're still youtube friends though ...And we hardly use those in my country

[@CookieTube]

@@TheFlamingPiano nice 👍... PS: consider my previous --reply-- wall of text my kind of spacing out 😉(+ giving the channel and algorithm an engagement boost..... I do like his content and how he truly reviews and explains such tools a bit deeper, instead of just a plain old unboxing)

[@stefanleontin9972]

Hy. It's Working for Chaisaw?

[@diy_Lab]

Do you know how accurate it is ? Thanks