Tachometer (RPM Meter) DIY or Buy How a 3 sensor outdoes a 29 product!
video description
Date: 2020-09-13
Related videos
Comments and reviews: 10
micha
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.
reply
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.
reply
Markus
03: 17 Why are there two different resuls? Probably because you totally messed up the contact measurement, because the two adapters included are ment to be placed in front of the motor shaft, so that they spin in the same direction, thats why there is one with sharp point, which is placed in a center drill hole of big motor shafts and a second one with a recess, for smaller motor shafts which doesn't have a center drill.
But again not products fault, more the operators fault.
reply
03: 17 Why are there two different resuls? Probably because you totally messed up the contact measurement, because the two adapters included are ment to be placed in front of the motor shaft, so that they spin in the same direction, thats why there is one with sharp point, which is placed in a center drill hole of big motor shafts and a second one with a recess, for smaller motor shafts which doesn't have a center drill.
But again not products fault, more the operators fault.
reply
kimsmoke17
Replace the offset adjust pot with an RC low pass filter. C to gnd, and R to +Vcc. The common between R and C connects to the anode of the IR photo diode. Through a small signal diode like a 1N4148, with the cathode connected to the common RC connection. Set the time constant of the RC to something like 15 Hz, say 10K and 1 uF. Add a resistor in parallel with the C to let the cap discharge slowly. 30 to 100K should be fine. Now the unit will set the offset automatically!
reply
Replace the offset adjust pot with an RC low pass filter. C to gnd, and R to +Vcc. The common between R and C connects to the anode of the IR photo diode. Through a small signal diode like a 1N4148, with the cathode connected to the common RC connection. Set the time constant of the RC to something like 15 Hz, say 10K and 1 uF. Add a resistor in parallel with the C to let the cap discharge slowly. 30 to 100K should be fine. Now the unit will set the offset automatically!
reply
Un
Regarding the 300 rpm, you're not following the min distance of 5cm (50mm) as per the manual.
Maybe that's why the reading is off. In any case it sounds odd that a commercial device doesn't measure rpm accurately while a simple DIY contraption can.
Especially at such low speeds. There must be something you're not doing right, and the measuring distance can be just that.
In any case it's nice to see your solution 3 module, an arduino plus some simple software: )
reply
Regarding the 300 rpm, you're not following the min distance of 5cm (50mm) as per the manual.
Maybe that's why the reading is off. In any case it sounds odd that a commercial device doesn't measure rpm accurately while a simple DIY contraption can.
Especially at such low speeds. There must be something you're not doing right, and the measuring distance can be just that.
In any case it's nice to see your solution 3 module, an arduino plus some simple software: )
reply
vopt1972
Hi Great Scott, I have the feeling that you missed something in the measurement of the rpm by contact. Indeed, your tachometer measures the rpm of its own head, and thus you must introduce a correction coefficient as the rate between the rotor head diameter and the tachometer head. The tachometer cannot know what is the diameter of your shaft!
reply
Hi Great Scott, I have the feeling that you missed something in the measurement of the rpm by contact. Indeed, your tachometer measures the rpm of its own head, and thus you must introduce a correction coefficient as the rate between the rotor head diameter and the tachometer head. The tachometer cannot know what is the diameter of your shaft!
reply
LeoDJ
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.
reply
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.
reply
Daniel
Coudln't agree more, long ago i made my own tachometer the same way you did, but instead of checking time between interrupts, i counted how many revolutions i get in 1 second, and then calculate how many in a minute, and display it using a simple 16x2 LCD display. less acurate, but it is what i could do myself back then.
reply
Coudln't agree more, long ago i made my own tachometer the same way you did, but instead of checking time between interrupts, i counted how many revolutions i get in 1 second, and then calculate how many in a minute, and display it using a simple 16x2 LCD display. less acurate, but it is what i could do myself back then.
reply
Karl
GreatScott - you mentioned a theoretical maximum RPM that can be calculated by the arduino, but do you have a sense of the practical maximum RPM? I was considering using this circuit and devices to measure the speed of a CNC spindle I have that tops out at 24000 RPM, and was wondering if this hardware can keep up?
reply
GreatScott - you mentioned a theoretical maximum RPM that can be calculated by the arduino, but do you have a sense of the practical maximum RPM? I was considering using this circuit and devices to measure the speed of a CNC spindle I have that tops out at 24000 RPM, and was wondering if this hardware can keep up?
reply
Krmpfpks
Contact measurement is off because of the gear ratio of your setup. Optical measurement should be quite accurate. Your frame count is inaccurate because of the frame rate, you should count the frames of multiple revolutions and average to get a better accuracy (assuming somewhat constant rotational speed.
reply
Contact measurement is off because of the gear ratio of your setup. Optical measurement should be quite accurate. Your frame count is inaccurate because of the frame rate, you should count the frames of multiple revolutions and average to get a better accuracy (assuming somewhat constant rotational speed.
reply
Fritz
Really nice video but please please stop doing these clickbait titles. Your 3 Sensor is maybe 10 Times better but normal consumers dont want to hold a PCB without case in their hands. What I want to say is that you should be a bit more objektive by comparikg also case and labour.
reply
Really nice video but please please stop doing these clickbait titles. Your 3 Sensor is maybe 10 Times better but normal consumers dont want to hold a PCB without case in their hands. What I want to say is that you should be a bit more objektive by comparikg also case and labour.
reply
Add a review, comment
Other channel videos
