Buttshock Arduino Shield

ButtShock Arduino joke logo thing
ButtShock Arduino joke logo thing

fluffybit and I have been working a lot with the MetaFetish/Buttshock people on interfacing with an ErosTek ET-312, as part of the project we looked at the internals of the box, and based on observations of the pcb, and other estim boxes out there the Buttshock Arduino Shield was born.

After a few back and forths the design stands at this:

We will be checking the design a fair bit more, then sending off to make some prototypes.

Written By Dvo

A Kinky Geek, MCR UK

24 Comments on “Buttshock Arduino Shield

  1. jen Reply

    June 29, 2016 at 5:08

    hey, since you are at it: another good thing would be a motor control, for different kinds of motors (brushless, brush AC, brush DC, stepper) to build a fucking machine that can be programmed ….. 😛

    like with rhythm variation programs similar to what you can to on exercise equipment, optimum would be a music input to control stroke and depth…..

    • Dvo Reply

      June 30, 2016 at 11:07

      If i can get this working, the thought is to add additional things to a shield for an Arduino Mega, so four channel, two H Bridge, and some other digital and analouge I/O

  2. Lupindb Reply

    June 30, 2016 at 8:57

    Very nice. Good thinking!

    • Dvo Reply

      June 30, 2016 at 11:06

      hopefuly if this works, I can make a four channel one 😛

  3. Onwrikbaar Reply

    June 30, 2016 at 10:31

    Your choice of transformer (42TL025) puzzles me somewhat. The filament that you use as the primary has a DC resistance of 150Ω. That means that your primary current will be at most 12V / 75Ω = 160 mA. With the transformer’s turns ratio of about 4, that would yield an output current of only 40mA. In practice even less, because of losses in the transformer. Is this fairly small output current intentional?

    • Onwrikbaar Reply

      June 30, 2016 at 10:33

      Correction: the turns ratio is almost 8, making the maximum output current even smaller.

      • JimS2 Reply

        June 30, 2016 at 10:36

        @Onwrikbaar, You were correct the first time: an impedance ratio of 17:1 implies slightly more than a 4:1 turns ratio. (a transformer’s impedance ratio is the turns ratio squared)

        (Engineering types please don’t flame: For simplicity, I’m going to use formulae here that are only valid for DC wattage)

        This transformer choice would yield heavy electrical losses and short physical life since up to 1.9 watts (12v x 0.16 A) would be supplied to a transformer designed to handle a maximum of 0.075W

        The theoretical 40mA output of that severely over-driven transformer, until that transformer melts either its primary winding or that winding’s insulation, would provide a stronger zap than most dog shock collars.

        If the OP were to stay within that transformer’s power ratings though, he could only get a barely perceptible 1.6mA out at 48V (0.075W / 48V)

        • Onwrikbaar Reply

          June 30, 2016 at 10:38

          Thank you, I hadn’t even considered the power yet.

          I expressed myself poorly. Only one half of the primary is driven at a time. The turns ratio between the secondary and half the primary is 8.5:1, leading to a theoretical maximum output current of 19 mA. Which is less than a quarter of what most cheap TENS units provide.

          In addition, a snubber circuit appears to be missing, so the MOSFETs are at risk too.

        • Onwrikbaar Reply

          June 30, 2016 at 10:38

          Concerning the power: so long as the transformer is driven with a duty cycle of at most 0.075 / 1.9 ≈ 0.04, it should survive. That would correspond to (for instance) 400 100-µs pulses per second, which probably suffices. TENS units usually don’t go over 150 pulses/s.

        • Onwrikbaar Reply

          June 30, 2016 at 10:39

          Argh. That ratio is not 8.5, but 2√17 ≈ 8.25. Oh well, close enough 😉

    • Dvo Reply

      June 30, 2016 at 10:39

      The transformer is the main component I am unhappy with. Can you recommend one from the same family?

      • Onwrikbaar Reply

        June 30, 2016 at 10:40

        From that family I’d try the 42TL021 first, for a device with moderate power. Even if something goes wrong in the software, you won’t get too badly buttshocked.

        Then if everything works as intended and you’d like more power, consider the 42TL026 and the 42TL004. With their very low DC resistance, your software will definitely have to monitor the primary current though (what I presume R1/R2 are for).

        On closer inspection of the circuit, a snubber may not be required. With the relatively large gate resistors and C2/C4, the switching is going to be pretty gentle.

        • Dokter_Ernst Reply

          June 30, 2016 at 10:41

          Interesting discussion about impedances, resistances and turns ratios. Here is a datasheet I found.

          • Onwrikbaar

            June 30, 2016 at 10:42

            @Dokter_Ernst: Good find!

        • Dvo Reply

          June 30, 2016 at 10:54

          @Onwrikbaar will be making that change from your recomendations 😀

          one of the problems is lack of source materials.

  4. Black|Box Reply

    June 30, 2016 at 10:43

    What kind of jack are you using? I recall there being several different types of plugs for e-stim toys, but I never discovered which one was the “most standard”. I can’t tell from the board footprint.

    It looks like you’re assuming that there’s +12V on the VIN pin. Is that right? Are you powering this with a simple unregulated wall transformer, or something more elaborate?

    I know I’ll have to modify this at least a little bit since if I used it I’d be powering it from an ATX power supply (I have a larger system to integrate into), but wow, any changes I’d need to make would be almost cosmetic.

    • Dvo Reply

      June 30, 2016 at 10:48

      @Black|Box The jacks are 2.5mm audio jacks, they were chosen just for there size, and cost, Farnell part number 1280745

      To interface with COTS (common off the shelf) I would recomend pig tails.

      The 12V is just VIN to the Arduino, I assumed it was going to be 9V nominal. however depending on the raiting of the Arduino main regulator you can choose a diffrent Vin.

  5. Lady_Robin Reply

    June 30, 2016 at 10:49

    WORKED this time. Suggestion(s) on how to find info describing the features – control functions etc. so I might be able to determine if I ‘have to have one’? >SMILES<

    Reminder, my old brain isn't new techno speak capable so things sorta need to be in simple language (for me to derive MAXIMUM benefit).

    • Dvo Reply

      June 30, 2016 at 10:51

      This at the moment is a Hardware project, the control board is a Arduino Uno R3, and hopefuly I will be able to find people willing to code for it 😀

  6. LanceLake Reply

    July 1, 2016 at 7:09

    So… What does it do? I see no details as to what it does.

    • Dvo Reply

      July 1, 2016 at 7:10

      It is a two channel e-stim Arduino Sheild

  7. Geek Reply

    September 29, 2016 at 5:07

    Has there been any further movement or updates to the schematics of this? Myself and a number of my geeky friends are very interested in this project.

  8. Rich Reply

    October 7, 2016 at 9:03

    Thank you so much for your work on this!

    I hope that you are able to get to the point of selling boards, populated or not, but whether or not you do that you have done a great service to the community. Bravo!

  9. aakv Reply

    December 5, 2016 at 4:11

    Hi… I’m working on better version of E-Sim project. I’m upload that project soon. but i have one question. Do you test your hardware with 42TL025, 42TL004. is this work?

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