Category Archives: Hardware


The first draft of the paper is done! It comes out at about 12 pages. I’ll need to cut it down to 6 to submit for CHI 2014 WIP. Easier than writing though. Of course, that’s just the first draft. More to come, I’m guessing. Still, it’s a nice feeling, and since I’ve burned through most of my 20% time, it’s time for me to get back to actually earning my pay, so I’ll be taking a break from this blog for a while. More projects are coming up though, so stay tuned. I’ll finish up this post with some images of all the design variations that led to the final, working version:

Prototype Evolution

Prototype Evolution (click to enbiggen)

The chronological order of development is from left to right and top to bottom. Starting at the top left:

  • The first proof of concept. Originally force-input / motion – feedback. It was with this system that I discovered that all actuator motion had to be in relation to a proximal relative base.
  • The first prototype. It had 6 Degrees of freedom, allowing for a user to move a gripper within a 3D environment and grab items. It worked well enough that it led to…
  • The second prototype. A full 5-finger gripper attached to an XYZ base. I ran into problems with this one. It turned out that motion feedback required too much of a cognitive load to work. The user would loose track of where their fingers were, even with the proximal base. So that led to…
  • The third prototype. This used resistive force sensors and vibrotactile feedback. The feedback was provided using voice coils, which were capable of full audio range, which meant that all kinds of sophisticated contact and surface effects could be provided. That proved the point that 5 fingers could work with vibrotactile feedback, but the large scale motions of the base seemed to need motion (I’ve since learned that isometric devices are most effective over short ranges). This was also loaded with electronic concepts that I wanted to try out – Arduino sensing, midi synthesizers per finger, etc.
  • To explore direct motion for the base for the fourth prototype I made a 3D printing of a 5-finger Force Input / Vibrotactile Output (FS/VO) system that would sit on top of a mouse. This was a plug-and play substitution that worked with the previous electronics and worked quite nicely, though the ability to grip doesn’t give you much to do in the XY plane
  • To Get 3D interaction, I took two FS/VO modules and added them to a Phantom Omni. I also dropped the arduino and the synthesizer and the Arduino, using XAudio2 8-channel audio and a Phidgets interface card. This system worked very nicely. The FS/VO elements combined with a force feedback base turned out to be very effective. That’s what became the basis for the paper, and hopefully the basis for future work.
  • Project code is here (MD5: B32EE89CEA9C8E02E5B99BFAF24877A0).

First Results :-)

Downloaded several wav files of sine wave tones, ranging from 100hz to 1,000hz. The files are created using this generator, and are 0.5 sec in length.

Glued the tactor actuators in place, since they kept on coming loose during the testing

Fixed the file outputEach test result is now ordered

Fixed a bug where the number of targets and the number of goals were not being recorded

Added a listing of the audio files used in the experiment.

Got some initial results based on my self-testing today: firstResults
The pure haptic and tactor times to perform the task are all over the place, but it’s pretty interesting to note that Haptic/Tactor and Open Loop are probably significantly different. Hmmmm.

Deadlines and schedules

I was just asked to see how many hours I have left for working this research. It turns out at the rate I’m going, that I can continue until mid-October. This is basically a big shout-out to Novetta, who has granted a continuation of my 20% time that was originally a hiring condition when I went to work for Edge. Thanks. And if you’d like a programming job in the DC area that supports creativity, give them a call.

I just can’t make the audio code break in writing out results. Odd. Maybe a corrupt input file can have unforeseen effects? Regardless, I’m going to stop pursuing this particular bug without more information

Fixing the state problem. Done.

Fixing the saving issue. Also changing the naming of the speakers to reflect Dolby or not. Done.

New version release built and deployed.

And back to Phantom++


I started to add in the user interface that will support experiments. Since it was already done, I pulled in most of the Fluid code from the Vibrotactile headset, which made things pretty easy. I needed to add an enclosing control system class that can move commande between the various pieces.

I’ve also decided that each sound will have an associated object with it. This allows each object to have a simple “acoustic” texture that doesn’t require any fancy data structure.

At this point, I’m estimating that the first version of the test program should be ready by Friday.

And yet more…

Got the wiring cleaned up.

Integrating collision response with the targetSphere. The math is looking reasonably good.

Added multi-target capability.

Added adjustable sensitivity to the pressure sensors. The pushing directly on the speakers is causing artifacts. I think I need to build small c-section angle that decouples the squeezing force from the Vibroacoustic feedback.

Dancing Phantoms

Spent most of the day trying to figure out how to deal with geometry that has to be available to both the haptic and graphics subsystems. The haptics subsystem has to run fast – about 1000hz and gets its own callback-based loop from the HD haptic libraries. The graphics run as fast as they can, but they get bogged down.

So the idea for the day was to structure the code so that a stable geometry patch can be downloaded from the main system to the haptics subsystem. I’m thinking that they could be really simple, maybe just a plane and a concave/convex surface. I started by creating a BaseGeometryPatch class that takes care of all the basic setup and implements a sphere patch model. Other inheriting classes simple override the patchCalc() method and everything should work just fine.

I also built a really simple test main loop that runs at various rates using Sleep(). The sphere is nice and stable regardless of the main loop update rate, though the transitions as the position is updated can be a little sudden. It may make sense to add some interpolation rather than just jumping to the next position. But it works. The next thing will be to make the sphere work as a convex shape by providing either a flag or using a negative length. Once that’s done (with a possible detour into interpolation), I’ll try adding it to the graphics code. In the meanwhile, here’s a video of a dancing Phantom for your viewing pleasure:

Eight channels of sonic goodness

After a frustrating couple of days trying to get my Vantec USB Dolby 7.1 unit working, I gave up and sent it back to Amazon. Who, I must say, in their vast, impersonal way, really did a good job. The new replacement unit was on its way and arrived the day I sent the old unit back on their dime. Pretty impressive.

After letting the device sit in its box for a while as I worked up the energy to try something that I suspected would not work, I finally tried it this morning, and it works like a charm. Yay! Now I noticed something different, so it’s possible that the old unit worked fine.

When I plugged in the new controller, I happened to notice that there was a new icon in my system tray:

And what does this do?

And what does this do?

Clicking the icon brought up a tool that I hadn’t seen before:

2 Channel Config

2 Channel Config

Note that the System input seems to default to 2 CH, though 8 are available. More importantly, on the right side of the screen note that the “DSP Effect” seems to be getting 2CH data that it then sends to all the speakers. This was the behavior that I was getting that I couldn’t seem to fix.

Selecting “8 CH” in the combobox has the following effect:

8 channel configuration

8 channel configuration

After making that change, I clicked on each of the speaker icons in the lower right image and was rewarded by a synthetic voice coming out of the appropriate helmet speaker. Hooray!

Now this configuration tool must have been installed with the device, but it wasn’t mentioned anywhere in the documentation and didn’t pop up in the install procedure. It looks like you just have to know that it’s there. I guess that’s not surprizing, in that all these USB systems use the same chipset, made by C-Media, and they wrote the driver.

Anyway, I now have a functioning system. I need to play around with the best way to have the actuators contact the user’s head, but I think that’s the last remaining hardware task.

I’ve also finished getting the correct speaker lead to go to the correct amplifier, and cleaned up the wiring harness. Here’s a picture of the leads coming off the helmet:

The latest style in HCC

The latest style in HCC

I’m sure that no one would look twice at me walking down the street wearing that and four glowing amplifiers strapped to my back…

Done with wiring. Well, for now.

Today’s job was twofold – get all the speakers wired up and test everything as a unit, and if that works, get a cheap bike helmet to mount them all to.


Eight Speakers and Blinky Lights

Testing was a breeze – it turns out that Windows has a nice control panel for configuring speakers:

SpeakerConfigAll I have to do is click on the speaker, which gives me a convenient tone. Otherwise, I’m not sure I ever would have been really sure as to which speaker was what.

Anyway, everything works. The next picture should be looking something like Rick Moranis  in Ghostbusters:

Early Proof-of-Concept

Early Proof-of-Concept

Ok, I’ve got the actuators mounted in the helmet and they work pretty well. The only problem is that the Dolby until is locked into stereo mode and I can’t seem to get it to think that it’s 7.1. Sigh. Guess that’s the problem for tomorrow…


Now with more wires

I managed to get all of the components hooked up around the amps today. Now I have the USB Dolby 7.1 decoder on top of the amp stack, with all four amps bolted together. I’m waiting to get a power strip that I can hook up all the power supplies too. But everything should have a nice blue glow when it’s plugged in. Tomorrow, I’ll hook up the speakers and see how it all sounds/feels.


Today’s laundry list

Not much progress, due to other classes, work, life-in-general. But I have a gap today so:

Meeting at PAD lab to discuss our cohort of projects

I’m going to swing by Home Depot on the way home today to get some .25″-ish threaded rod and nuts so that I can make a tiny rack for all the amps. They also sell Y-adapters, so I’ll pick up a few more of them. Pix by the end of the day, with luck.

And I came across this cool thing:  $59 pcDuino – AllWinner A10 Board with Arduino Compatible Headers. Here’s a picture:

And here we go – the world’s cutest 8-channel amp: