Help intagrating hertzmeter into analog linear power supply

Click For Summary

Discussion Overview

The discussion revolves around integrating a frequency measurement system into an old linear power supply (HP 6284A) for the purpose of measuring the speed of a tattoo machine. Participants explore various methods, tools, and circuitry needed to achieve this, including analog-to-digital converters, microcontrollers, and alternative frequency measurement devices.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Experimental/applied

Main Points Raised

  • One participant suggests needing circuitry to measure the waveform of the output current, an analog-to-digital converter, and a microcontroller to analyze the waveform.
  • Another participant proposes using a universal frequency meter or specialized frequency meters as a simpler solution.
  • Some participants express uncertainty about how frequency measurement works with a DC output from the power supply.
  • Using sound and mobile apps to measure frequency is suggested as a simpler alternative, though concerns are raised about the effectiveness of such apps at low frequencies.
  • One participant mentions the frequency range of musical instrument tuners and questions if they can register the desired frequency range for the tattoo machine.
  • There is a discussion about the relationship between voltage adjustment and machine speed, with some participants asserting that voltage does affect speed.
  • One participant proposes a method to determine frequency by matching the sound of the tattoo machine to an adjustable tone generator while varying the voltage.
  • Concerns are raised about how different needle groupings might affect the load on the tattoo machine and thus the frequency readings.
  • Some participants provide generally accepted frequency ranges for different types of tattoo machines.
  • Suggestions for building a DIY analog output frequency meter are provided, alongside recommendations for prebuilt options.

Areas of Agreement / Disagreement

Participants express multiple competing views on the best approach to measure frequency, with no consensus on a single method. There is agreement that voltage adjustment affects machine speed, but uncertainty remains about how to accurately measure frequency in this context.

Contextual Notes

Participants highlight limitations related to the accuracy of frequency measurement methods, the dependence on specific definitions of frequency in relation to tattoo machine operation, and the impact of varying loads on frequency readings.

Who May Find This Useful

Individuals interested in electronics, tattoo machine operation, and frequency measurement techniques may find this discussion relevant.

DyingART
First off I'm not an engineer nor do I have a electronics background.
I have an old Linear (HP 6284A Power Supply). I would like to be able to display Hz/CPS.

I need to measure the speed of a tattoo machine. (basically two coils that make and break connection through out its use.

From what I gather I need circuitry to measure the waveform of the output current, an analog-to-digital converter to get that waveform data into a microcontroller, a microcontroller to analyze the waveform, software to extract the three time intervals.

Or is there is there a simpler way?
Help?!

What do I need to buy to make this work :)
 
Engineering news on Phys.org
Some universal meters (like this one) measure frequency. About $40 on ebay. Plus many more specialized frequency meters that will be even cheaper. Won't they suffice?
 
  • Like
Likes   Reactions: DyingART
I'm not sure how they work.. The output for the power supply is DC so...?
 
There is a much simpler way. Use the sound. There are apps for phones and tablets that display the frequency of a musical note.
 
  • Like
Likes   Reactions: DyingART and Asymptotic
Interesting.. Though the Hertz level will be between 0-120. I'm not sure a program designed for musical notes will register that low? I'll try it. I would really like to integrate it into the power supply and build something like this. http://criticaltattoo.com/cx2r-g2/

This isn't for profit BTW.. Its for personal use. I would just buy a power supply for the job but they are expensive and hardly quality power.
 
If you play guitar you might have a tuner handy. The frequency range of my $25 Korg CA-30 tuner is listed as C1 through C8 (32.7 Hz to 4186.1 Hz), but it registers down to about 31.79 Hz (50 cents under C1). My guess is most musical instrument tuners don't go down very much farther than that (the lowest piano key, A0, is 27.5 Hz).

An HP 6284A supply is rated is 0-20 VDC at 0-3 amps. Is it fair to say that voltage adjustment doesn't affect machine speed?
Do you want to measure speed for machine adjustment?

Another approach is to run the tattoo machine, and adjust the frequency of a tone generator until it's output tone matches the tattoo machine.
 
  • Like
Likes   Reactions: DyingART
Voltage adjustment does affect machine speed. Would be nice to know the speeds.
 
DyingART said:
Voltage adjustment does affect machine speed. Would be nice to know the speeds.
Does loading affect speed appreciably? If not,

1. Operate the machine at full voltage. Determine the frequency by matching it's sound to an adjustable tone generator. Record voltage and frequency.
2. Incrementally reduce voltage by a small amount (say, 0.25V). Find the new frequency. Write it down. Continue this until at zero volts (or at whatever low voltage stalls the tattoo machine).

My guess is the relation between applied voltage and tattoo machine frequency is fairly linear and repeatable. Once you've determined voltage versus frequency, adjust the machine to whatever voltage yields the desired speed (frequency).
DyingART said:
I need circuitry to measure the waveform of the output current, an analog-to-digital converter to get that waveform data into a microcontroller, a microcontroller to analyze the waveform, software to extract the three time intervals
Doing something like this is an option, although probably not by directly measuring pulsations in output current, but rather by adding a low ohmic value resistor, and measuring voltage drop across it.

If there is a dramatic difference between high and low current demand per cycle it should be possible to isolate and count the high current pulses, and scale them to display in CPS. The less dramatic the difference in maximum and minimum current demand, the harder it is to tell them apart, and more difficult it is to determine machine speed through current feedback.
.
 
  • Like
Likes   Reactions: DyingART
GENERALLY ACCEPTED HERTZ/CPS Readings:
Liner 130 to 145
Shader 105 to 120
Color Packer, 95 to 115

The problem with recording voltage vs frequency incrementally Is the load on the springs/coils of the machine will be different with different needle groupings (weight).
 
  • #10
DyingART said:
GENERALLY ACCEPTED HERTZ/CPS Readings:
Liner 130 to 145
Shader 105 to 120
Color Packer, 95 to 115

The problem with recording voltage vs frequency incrementally Is the load on the springs/coils of the machine will be different with different needle groupings (weight).
Those speed ranges are well within musical instrument tuner capabilities. Here is a KLIQ Metropitch as an example. I can't tell if it displays in Hz as well as in musical pitch (on my Korg, the Hz value is calibration above and below 440 Hz, not note frequency).

It may seems strange at first, but if the idea is to repeatably tune the tattoo machine to a particular speed then use a chromatic tuner, and think about the speeds in terms of musical notes (130 Hz to 145 Hz is just about C3 to D3)
 
  • Like
Likes   Reactions: DyingART

Similar threads

  • · Replies 2 ·
Replies
2
Views
2K
Replies
17
Views
10K
  • · Replies 7 ·
Replies
7
Views
2K
  • · Replies 41 ·
2
Replies
41
Views
7K
  • · Replies 4 ·
Replies
4
Views
3K
  • · Replies 5 ·
Replies
5
Views
2K
  • · Replies 1 ·
Replies
1
Views
3K
Replies
5
Views
4K
Replies
13
Views
3K
Replies
2
Views
4K