The Hammer: A Muscle-Controlled, Light-Up Dildo

I'm proud to present my latest creation: The Hammer!  The Hammer is a prototype test-your-strength game that's an insertable, muscle-controlled, light-up dildo. Update, 1/5/13: The Hammer has been listed as's #1 Geekiest Sex Toy! Welcome, everyone!

Like innovative sex/kink-positive projects? Maybe you have an idea of your own, but need to raise some money? Check out my new startup, Passionate Produce!

The Hammer Is My Penis

Update #1, 10/11/12: If you would like to hear me talk about how I made The Hammer, you can see some excerpts and my slides from my technical talk at Arse Elektronika 2012.

Update #2, 10/11/12: The Hammer + animated GIFs = Win!

Update #3, 1/5/13: See The Hammer in Person! (Ignite Craft Boston, Arisia)

When the bulb of The Hammer is squeezed, the shaft lights up.

When the bulb of The Hammer is squeezed, the shaft lights up.

The Hammer has 12 individually-addressable RGB LED's to make it a glowing, rainbow cock!

The Hammer has 12 individually-addressable RGB LED's.

Since I was young, I've wondered what it would be like to have a bio-cock. Unfortunately, this is an experience I am unlikely to have. It's at least some consolation that now I have the most beautiful, glowing, rainbow penis in the world.

I've been working on The Hammer for a couple of months. It contains two force sensors, a strip of individually addressible RGB LED's, and an accelerometer. It connects to a custom-built prototype Arduino shield, and I programmed it using the Arduino software development environment. The toy itself is made of platinum cure, body-safe silicone.

Why call it "The Hammer"?

I originally named it after a Test-Your-Strength game in the Musee Mechanique in San Francisco. I then realized:

  1. When all you have is a light-up cock, everything looks like it needs to be nailed.
  2. The Hammer is my penis.

What can you do with The Hammer?
  • Receive visual feedback for Kegel exercises or physical therapy
  • Have a lightsaber duel
  • Get a blowjob or handjob in the dark
  • Watch the Hammer change color as you orgasm
  • ...or anything else you can program!

Right now The Hammer has two modes: the test-your-strength game, where the more you squeeze, the more it lights up; and a demo mode which cycles through all of the colors of the LEDs.  Soon I hope to connect the Arduino to my Android phone, and then I'll be able to do even more cool things!

I'll be following up on this with more technical details over the next few weeks. (Update, 10/11/12: If you would like to hear me talk about how I made The Hammer, you can see some excerpts and my slides from my technical talk at Arse Elektronika 2012.) My plan is for The Hammer to become an Open Hardware project.  This is still very much a prototype, but I would be thrilled if anyone else wanted to build their own.

I'd like to thank Jimmie Rodgers, my friends at Artisan's Asylum, and the teasecraft-boston meetup group for all of their help, ideas, and encouragement! I'd also like to thank Monochrom for giving me the opportunity to present this project at Arse Elektronika 2012.

What's my latest and greatest endeavor? I'm launching Passionate Produce, a new sex/kink-positive crowdfunding startup. Is this relevant to your interests? Subscribe to my newsletter!

Last edited 4/19/13: Reposted the video. Now it should stream correctly, and I won't have to worry about any more takedowns!


The Hammer: A Muscle-Controlled, Light-Up Dildo — 121 Comments

  1. Well done! I hope the Arse Electronica attendees were suitably impressed.

    Since you’re gathering info indicating you’re considering selling copies of your invention, I suggest you emphasize that it’s made from medical-grade silicone.

  2. The experiment of the Hammer is awesome but the design of the dildo one of Tantus’, The Feeldoe(R). The Feeldoe is a patented product for both design and use patents D376.650, D384.156, D384.158, and 5.690.603. While I applaud your making The Hammer an Open Hardware project, please respect the patent.

    Thank you.

    Metis Black
    Tantus Inc. President and Founder

    • Thank you for your comment! The Feeldoe is a great product — I own a couple, which is one of the reasons why I used it as a basis for this prototype. Obviously a lot more engineering work would be required before this concept would be ready for consumer use, not the least of which would be a new design which respects existing patents.

        • Oh wow. I just saw this now, and … well, I own four Feeldoes. This sort of behavior makes me want to never buy another. :( I hope this has been well-resolved by now, and in a good way that is respectful of existing products and new innovations.

          • Thanks for taking the time to comment! I mean…I still think the Feeldoe is a great toy, and I’m still in favor of people purchasing them. It’s not exactly resolved yet, but that’s largely because most of my efforts are going to Passionate Produce. I still plan to produce my own toy some day, and by then, who knows — I’ll either find someone to help me sculpt a new design, or else by then all of the existing Feeldoe patents will have expired.

            There certainly *is* theft that happens in this business, and I can understand why people want to be hyper-vigilant. It’s just a little frustrating when folks get upset over things that are actually legal.

    • You’re hilarious if you think that your patent holds any claim to this. She’s engineered something different using entirely different methods from your own. Just because she’s used one of your products in the building process doesn’t matter. It’s a non-issue. You can’t touch her any more than the company that made the wires coming out of the back.

      Imagine that you make birdhouses for a living, instead of dongs. It’s like a company that makes nails threatening you because you used their nails to make the birdhouses you’re selling.

    • Hello Ms. Black,

      I have a lot of respect for your company and I enjoy quite a few of your products. I certainly understand your need to protect your intellectual property.

      I strongly suggest you reach out to Kristen in a different way. Instead of commenting here with a warning about your patents, why don’t you send her a direct message and see if it may be beneficial for the two of you to work together on bringing this product to market? The Feeldoe is a fantastic basis for this idea. Why would you not want to incorporate a new idea and bring another amazing product to market?

      Your other option is to get defensive and make veiled threats about your patents. The result of which would be a similar product with a slightly different design, competing directly with your products (with the edge of novel technology). However this might end up for you, it is clearly the less attractive option. I urge you to consider otherwise.

      Andrew B.

    • Hello M. Black, Kirsten and Andrew B.,

      I have been conceptualizing a prosthetic device for a few years now. However, I came across your design of Feeldoe, which somewhat achieved what I had in mind, yet it was much simpler! The design still amazes me and I am still eager to buy one! But Kirsten has taken a step forward by adding the force sensors and actuators (in this case LEDs). I would agree with Andrew B’s comment. A collaboration between two parties would result in an amazing product (and the toy of my dreams): Why not put the force sensors (and light sensors) on the shaft, and put the actuators (this time a simple series of vibrators) in the bulb, and code the actuators to be driven by the light/force info from the shaft. There. That’s close enough for a penis. I had this idea for some years now, and despite the fact that I work in a field not too far from the topic, there’s never enough time and I am not getting any closer to realizing my idea, please make it happen, i will buy one! :D

      Once again, amazing job Kirsten!

      • Hi, and thanks for writing! That is a cool idea, and you’re definitely not alone in your interest — I have another friend who’s been playing around with the prosthetic idea, too. I really feel like there are a lot of potential toys to be made combining sensing and actuation in different ways. You might also want to keep an eye on my friend Dr. X. Treme’s work; he’s got a new toy coming out that uses sucking a dildo as actuation for a vibrator:

        Update, 12/14/18: Aaaand the original link doesn’t work since he went out of business a few years ago. Replaced with a link to the Internet Archive.

    • As it happens, I designed the custom Arduino shield with space for a bluetooth radio — so yes, someday it will have wireless control.

      The toy is too fragile right now to consider using it as an insertable, so I don’t have a good answer for that. In general the current sensor really isn’t sensitive enough to pick up the muscle contractions that I want; I have to engage my entire core to light it up right now.

      Thanks for the comment!

      • as a lady, i’m not sure if you have thought of this, but it might be better in its current form for gay men. anal muscles are stronger than vaginal ones, and can exert the required pressure much more easily, but using it to penetrate another man would be fairly essential for us so it would need to be made of tough materials. as for the vibration mentioned in the survey, you should make sure both parts vibrate. and if you make the shaft vibrate, make sure the whole thing vibrates. i know base vibration is great for ladies, but we use our prostates and nothing makes us sadder than a toy the vibrates at the base while the head just sits there. it looks like the shaft has room alongside those leds, so may i suggest a row of vibrating mechanisms to ensure full length transduction?

        • Thanks for the comment! My gender is actually kind of complicated (so I’m not sure “lady” is quite the right term). A lot of folks have suggested adding more vibration — the problem is impedance matching. You’ve got to have a *lot* of power to move both the entire shaft of the toy as well as whatever fleshy bits you want to actually feel the vibration — and it’s tricky to fit that much power in a reasonable form factor. (More info on this in my interview with Doctor X. Treme: ).

      • What about using an air/fluid pressure sensor in the shaft and having the bulb a sealed chamber with air or a fluid in it so that any subtle squeeze on the bulb can be accurately measured.

          • Yep! 3D printing is definitely a good option for toymaking if you have access to one (Kenton of Funkit Toys makes all his toys by 3D printing his molds). Good stuff, thanks for writing! – Kit

  3. Wouldn´t the USB Power Delivery standard be a usefull connection for electrify this kind of lighted and maybe vibrating toys!
    The USB Power Delivery standard will make it much easier and safer to not be forced to use batteries in this kind of sex toys.

  4. Pingback: See The Hammer! (Ignite Craft Boston, Arisia) | The Toymaker Project

  5. This looks awesome and I would be very interested in it when it’s complete. I know it’s asking for a lot but a vibrate function would be quite nice.

    Also, very happy to hear it’s 100% silicon; please make that very clear when you advertise, I hate having to search for important information like that.

    • Thanks for the suggestions! Vibration is tough (see above comment), but I will be sure to mention the fact that it’s body-safe silicone more prominently, especially going forwards.

      • I just wanted to say that since posting this I’ve looked up the survey and the talk you gave at Arse Elektronika 2012; I couldn’t be more impressed. I understand vibrate functions would be rather tricky and applaud you for trying, I hope you find a way to make it work! Though if not then a brilliant rainbow cock is magnificent in its own right.

        Needless to say I’ll be keeping a good eye on this project and can’t wait to see how it goes. The idea of Lightsaber sounds for it made me grin I have to admit and even if they don’t end up added I know what I’ll be imagining.

  6. Hello, Cracked reader here. Just had to click the link when I saw that pic of you making the Hammer light up… without using your hands. It can’t be easy to make a dildo that makes a straight guy say “That kicks ass.” This is a wonderfully kinky innovation, and I adore you.

    • Thank you! :) Yeah, it’s been a pretty interesting project to work on in a lot of ways. Initially it was all technical challenges. Now that it’s been built and I have opportunities to tell people about it, there are more social challenges. This is a toy that pretty much anyone could use (or have used on them), regardless of your gender or orientation — but I don’t think a lot of other people see it that way.

      We’ll see what happens! At the very least I hope it inspires other folks to start playing with more electronics and silicone…and maybe it will encourage some folks to step out of their usual comfort zones.

  7. *Note to everyone regarding patent comments:* I appreciate the show of support, but I won’t be posting any more negative patent comments. Regardless of what anyone thinks about how the patent system operates, I’ve got to play by the rules. I do have lawyers who I consult with on these issues (both my sex-positive-business lawyer and a friend who’s a patent attorney).

    In any case, most of those Feeldoe patents are already expired.

  8. Pingback: BDSM 101 « shyblackbird

  9. We demand to see it in action for testing purposes. see how much thrust and friction can handle. any volunteers in the name of science?

  10. Pingback: The Hammer: Muscle-controlled, Rainbow-LED-Dildo › Nerdcore

    • Most of my effort right now is in launching my crowdfunding startup so that I’ll have a way to raise the money to actually get these produced — join the email list at to keep up with that. :) So that’s going to be most of my effort for the next half-year, probably. After that, we’ll see.

  11. Pingback: ‘Introducing’ The Hammer | cordltx

  12. When you get these bad boys done (and hoping there’s a resolution w/ Tantus) I MUST HAVE ONE FOR REVIEW!!! Those lights, the colors, the whole damn thing – it’s GENIUS! Bravo!!

    • Ahhh, yes. So Kickstarter and IndieGoGo have terms of service which forbid sex-related projects…which is why I’m starting my own sex/kink-positive crowdfunding site, Passionate Produce. The Hammer is on hold until I’ve created the right platform to fund it.

  13. Hey, saw one of the earlier posts showing two buttplugs, one that lit up and another that would be squeezed.

    What about this for a project? Two squeezable bulbs, and a bar of LEDs on a board.

    Make it into some kind of game to squeeze harder, or in a certain way. Dunno how the mechanics would work to make it fun for two people to use, but there could be the sensor in each one and a little motor.

    • Fun! Yeah, those bulbs were my proof-of-concept for the Hammer. :) You could definitely hook multiple sensing toys together and then share the output (either work together to do something, or compete to do something)!

  14. This is a game I would win. Gynaecologists, doctors and my pelvic physiotherapists agree that I have an unbelievably strong vagina. It has made some men cringe in pain. I am more than a match for your device. I can’t wait to try it, YAY! Now my girl bits can make LIGHT SHOWS!

  15. You mister doctor ma’am are both a scholar and (dare I say) genius. I have one suggestion, perhaps an acceleromator to enable a light up mode based on vigor (instead of only muscle contractions)…

    Two fun games in one!

      • Thank you!

        Vigor detection is an awesome idea! I suspect you could probably get the accelerometer to give you usable data — it should be able to report back-and-forth motion along any of the axes. Lighting up according to that would be hilarious. :)

        Unfortunately, this runs into the general problem I have of the device not being robust enough for vigorous use! Flexion in the shaft tends to cause the components on the LED strip to become disconnected. I have some ideas about how to work around this, probably by encasing the electronics in the shaft in a firmer silicone core.

  16. I have been looking for light up dildos for ages most places have stoped making them. If this thing could come in just the shape of a dildo and a button where u can turn the beautiful lights on that be amazing I know so many strippers/entertainers that would love a new light up cordless dildo for there strip shows. Do u think u bring sumthing like that out and how long do you think it be till they are out ???

    • Thanks for the feedback! I definitely want to do a non-insertable version that just lights up. :) I don’t have much experience working with dancers/strippers/entertainers — What kind of control would be the easiest to use? Something small that’s handheld? Or would it make sense to have someone offstage with something like a smartphone who could control it? With a toy mainly used as a prop for a show, should it be made of silicone, or would plastic work?

      So, yes, I definitely want to do this. Timing is the hard part! First I have to launch my startup ( and get that rolling, then I’ll be able to use that to do fundraising for new toy development. It may well be six months or a year before I can do the fundraising, then another six to nine months for actual production.

  17. blokes would be interested too…

    have you thought about butt plugs?

    Could go the route of tails for the anthropomorphic slave and furry crowd.. (puppy slaves, ponyboys, alien bondage and probe scenes) a novelty and niche market but likely to generate serious interest in the fetish and comicon communities.

    or combine buttplug with a cockring / dildo harness… maybe with upgrades (plugins) to a half or full harness.

    silicone for the plug and ring (control), but you might be able to get away with plastic for the harness.

    But whether for personal or public scenes, events, the dungeons, club or baths, that might be a bit too rough to wear for extended scenes unless it was fitted with another material for comfort… if it can’t hold up for extended wear, the market narrows or the cheaper ‘raver’ alternatives will be used.

    ‘course a few would like even higher quality materials — that might make it an art piece onto itself — which would require getting tech minded crafters involved… with a little steampunk or rivethead flare. There are so few innovators of higher quality goods. (highest value; less about bling than creative technology and fashion… there’s options to be had with blown glass, being used as little else than a conduit or a reflector, giving the appearance of a violet wand without the sting. The crowd interested in those sorts of toys are likely to spend several hundreds more for quality options.)

    and of other toys, accessories…

    consider an option for a breathing apparatus for costume play, or for the bdsm scene.. gags — to which you could market it as a silent safeword. — a practical option to introduce people to your other wares.


    for interactive and contact entertainers: it’s just that, making it interactive…

    — something that caters to the pavlovian, respondent, conditioning… that heightens the anticipation of the audience….

    an aspect which can also be tossed over to the bdsm scenes as well… like a paddle’s whack.

    but there’s so many variables to performance..

    fire and electric dancers may be too abstract for thought…

    so maybe one might look at the performances of belly dancers instead… so many options for the control and design

    (… oh, I bloody forgot what it’s called, there’s a ball dance (not the fakir ball dance, though that could be entertaining as well) one in which a ball or piece of fruit is exchanged between two partners, without the use of their hands… it’s meant to be more of a sensual, sexual dance than comedy of errors it might play out in the west. The point in mentioning it is it’s a good exercise for exploring human anatomy and sensual movement… which should help with your design.)

    (and for strippers, I’d suggest checking out “the stock bar” +montreal

    to which plugs and cockrings that respond to flexing would be shown as ideal.

    on the other side, for chicas, the belly dancers or female rockers, the heavy metal crowd… alternatives are needed for several venues to the use of saws, grinders, electro or fire.)

  18. Pingback: Working with Silicone for DIY Toys | The Toymaker Project

  19. as per the tail comment above, once you get the general arduino platform down and move it over to a micro-uino style board or w/e, i think i product you may do well with would be a simple force sensor + plug/fiberoptic thread tail. like those kids toy wands with a 3-7 color led in the base and 1-3 feet of clear fiber whip. the stuff has to be cheap by now, they make xmas trees outta it.. but yea, anthropomorphic rave butt.. i see some kind of kink niche there.. every spank/clench causes the colors to cycle etc..

    love the ideas/work you have shown =]

    • Nothing’s for sale here, this is just a prototype. I’m hoping in a year or so I’ll have enough time to devote to building a new toy that’s ready for mass production!

  20. Pingback: The Hammer goes to Burning Man! | The Toymaker Project

  21. I wanted to let you know this is is the most inventive idea I have heard in a long time. Keep up the brilliant work!