Tachometer (RPM Meter) || DIY or Buy || How a 3€ sensor outdoes a 29€ product!

Parts list (affiliate links):

In this episode of DIY or Buy we will be having a closer look at a commercial tachometer (RPM Meter) and test it in order to find out that it is pretty much unusable. Afterwards I will show you how a 3€ IR distance sensor works and how we can use it to build a proper DIY tachometer that functions properly. Let's get started!

Thanks to JLCPCB for sponsoring this video

Music:
2011 Lookalike by Bartlebeats
Killing Time, Kevin MacLeod

[greatscottlab]

Sadly there is a small mistake in the video. The IR photo diode is positioned the wrong way around. Just imagine the cathode and anode being flipped. Sorry. (Edit: Ok, there is a second mistake. I used the roller adapter in contact mode incorrectly. I just did another measurement the correct way and measured an RPM of 270 while the correct one would have been 230. So this way it was a bit better but still not good enough for me.)

[DJ-Manuel]

Now you‘re just missing a 3d printed case for it and then it would be perfect 👍

[pewster]

One of my favorite parts of your videos is watching you write. Your handwriting is impressive!

[christopherguy]

I laughed when see you're sponsored by JLCPCB but build just using perfboard.

[Tapitus-totalus]

0:52 it's kind of cheap for tachometer in comparison to others

The $16 tachometer down there:

[LeoDDJ]

Great video, very informative and practical.
Just a thing I noticed, because I stumbled over it not too long ago myself: The two pixel white strip to the right of the OLED (10:03) is most probably caused by a wrong display type. If you have a SSD1306 but initialize it as a SH1106, or the other way around, you get those strips.

[emanuelxavier]

Once, I made a tachometer using a hall sensor effect and a magnet, but this way with the IR sensor, looks much better. Great job!

[fahb]

Men the diameter of the rolling thing is affecting the values, smaller more turns bigger less turns, you got to used aligned, not in besides

[emersonsrandomvideos]

I really like the way how great scott explain electronics without straining the time limits of his videos.

[ZeroMass]

Who else starts their Sunday morning with a cup of coffee and a slogan of " let's get started"?

[yagneshpatel]

i love to see diy win . it so happy our own made product work so fine . i give joy and emotions own hand made things

[nixxonnor]

I bought a similar RPM counter 10 years ago. It came without any of the accessories. ("Digital Laser Tachometer with Pouch When I measured a 5400 RPM hard drive platter, the display read 5399 - 5400.

[puriap]

Yes! DIY wins!!
I always wanted to do this project and find out how accurate these IR sensors can measure RPM. Thanks for doing it for me!

[kreature]

A tip for expansion later: Add a graph of the rpm over time on the lovely Oled display! Would be nice to see if rpm oscillates on things as well! Very few meters can do that.

[Appregator]

You've got the best left hand writing skill I've ever seen. You're a phenomenon !

[michaegi]

That's again is a wonderfull video. I like the DIY or BUY series. Over the past few years, I more often to go DIY. Not just because it's cheaper and I learn while building, but also because I can repair easily and recycle parts if I don't need the device any longer.
Thank you for all the fresh ideas.

My actual project is a weather station that saves the weather data to an NAS. So I have the complete history available and have at the same time a better accuarcy for temperature, humidity and rain quantity than I got from standard weather station. As a side effect I can easily display abolute air humidity or dew point, which is not available at normal weather stations.
I also plan to display a recommendation for room ventilation based on comparing temperature and (absolute) humidity.
The internal (display) part might be upgrated by an air quality sensor in the near future, which will improve the ventilation recommendation.

[bhu]

I miss the good old days when great scott used to make prefboards with clean satisfying soldering

[abdullaalmasum]

Just talk about the pens you use sometime.😂 hand writing is soooo smooth!!

[paulmeynell]

Thanks for this, I built it but was getting twice the rpm my scope said ! I have changed 120 in the code to 60 and now it works perfectly.

Thanks for a great project.
I am going to run it off of an 18650 a fuse instead of the charging board . On the occasions I want to use it I will put in a battery. This keeps costs down for something it will use now and again.

[rimooreg]

@GreatScott. Thank you for including the Entire Creative Process, including misadventures and commenters input. Makes for a more interesting and interactive experience for me. I use DC motors and motor controllers in the Mobility Industry and am drawn to invasive videos such as this. Thank you and your excellent commenters. Too bad I caught this one so late. I blame YouTube for poor notification.