2014-08-10 (Su) Arduino Powered Tattoo Machine Controller

If you do an image search for "tattoo machine diagram" on any popular search engine you can find the names of the parts I've mentioned in this blog. In fact, adding the word "diagram" to your search queries for technical items is a good idea. There is a lot of crazy stuff out there and the word diagram is pretty safe.

Enough background.

The mass and resistance on the armature bar of the tattoo machine was likely the cause of the inoperability. The added mass and resistance was due to the dashpot which added the mass of the plunger and the resistance of the air valve. While this was a small load it was greater than the coils of a tattoo machine were intended to handle.

The dashpot was disconnected from the armature bar with a ¼” wrench. The dashpot and bracket were then removed by taking off the stainless steel #10-32 countersunk bolts. This also disconnected the electrical again and since the traditional attachment location of the isolated front binding post won’t work one of the stainless steel bolts was reinserted to act as the terminal. A washer, locknut, and nut were used to attach to the chassis. The front binding post and contact screw were reattached but not the front spring. Once the contact screw was aligned it was fully removed from the binding post.

 Disconnected dashpot
Disassembling the dashpot bracket
Bracket removed from the tattoo machine
Front binding post reattached to the tattoo machine
Electrical reattached to the tattoo machine

A small suction cup was purchased to act as a cushion for the vibrating armature bar in place of the dashpot. The idea was that by removing the mass from the armature bar, but still providing a soft cushion, the natural frequency of the spring would be eliminated but not overpower the magnetism of the coils. A 1mm drill bit was twisted by hand to cut a hole through the suction cup directly through the center. The contact screw was forced into the hole by pressure and twisting to ensure it would fit once reattached to the tattoo machine. Once attached, the machine was inspected and set up with the control box again.

 Suction cup, 1mm drill bit, and contact screw

1mm drill bit through a suction cup
Contact screw through a suction cup
Suction cup/contact screw in place on tattoo machine
Tattoo machine with contact screw to act as a soft limit

Close up of suction cup pressing on armature bar
Tattoo machine attached to control box

The first test was without using any kind of limit and only to find the natural frequency of that tattoo machine. This is the frequency at which the armature bar oscillates when 12vdc is applied. This could be the upper limit of the control. The frequency was found to be approximately 79 punctures per second or 79Hz.

Finding the natural frequency at 79Hz

The second test was to move the cushioned contact screw into place to see how the frequency could be controlled when given a cushioned upper limit. The machine still did not give a usable amount of travel.

Using a soft limit

The third test used the contact screw as a hard limit to control the frequency. No usable travel was obtained.

Using a hard limit

To do:
  • Reprogram to use duty cycle
  • Determine upper frequency limit at a given voltage

 Journal page 1
Journal page 2

The rest of the posts for this project have been arranged by date.

A list showing of all the final posts of COMPLETED projects.

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