Arduino BT pressure glove DIY suggestions?

Hi all,

I'm interested in building an Arduino-based (wireless) pressure glove similar to the TouchGlove made by I-CubeX (sorry, not allowed to give a link on my first forum post: google "i-cubex glove") for a music project I'm working on.

The glove would need to have 5 pressure sensors, one in each of the fingertips and thumbtip. I understand that the piezoelectric pressure sensors used in existing gloves are sensitive to continous changes of pressure across a range of values - my glove would need to work like this, returning presure values for all 5 sensors simultaneously, sensitive to forces ranging from very light fingertip contact, up to the maximum force that can be applied by fingertips squeezing together.

My questions are:

  1. Can anyone suggest specific pressure pad components that would suit this application? (The cheaper the better!)

  2. Could such components be conntected directly to the Arduino board, or would intermediate circuitry be required? If so, what kind? If not, are there enough pins on the BT board to connect 5 pressure sensors to?

  3. Is it possible to have the board ultimately generate MIDI events from the glove, i.e. NoteOn/Off for pressure/on off contact (above/below a specific threshold), and CC events for pressure values from each sensor? From reading the Arduino site it seems this kind of thing is pretty commonly done, but if not, can I read raw data from the board/glove into an application written in C, in a Linux environment?

And a couple of secondary questions:

  1. As a possible extension, I'd be interested in adding a Wii-style accelerometer/gyro to the glove. Can anyone suggest a specific component for this, and suggest how many pins it would need on the Arduino board? Is it likely to need a separate board, or could it possibly somehow share the same BT board with the pressure sensors?

  2. Can the Arduino BT connect to a PC at the same time as another bluetooth app? Or would they i.e. each need their own Bluetooth dongle?

Thanks in advance for any help/pointers/suggestions anyone can offer on the above. Looking forward to making my own pressure glove on the cheap with Arduino!

-Luke

Do a board search for "force sensor" like below to get yourself started. Bare in mind that if what you want to do is cheap/easy, you would see many people making them.

http://www.google.com/search?ie=UTF-8&oe=UTF-8&q=force+sensor&btnG=search&domains=http%3A%2F%2Fwww.arduino.cc&sitesearch=http%3A%2F%2Fwww.arduino.cc%2Fcgi-bin%2Fyabb2%2F

textchimp:

Number one, good luck in getting the pressure response you are looking for; it isn’t going to be easy in a homebrew system. With that said, it is possible to homebrew something up…

The cheapest way to go would be to use anti-static foam as a pressure sensor; such foam is impregnated with a form of carbon that is fairly conductive - as you squeeze it, the resistance changes. Use conductive epoxy (arctic silver, for instance) to attach the wires to it, then experiment.

You might also try experimental conductive glue; an individual out there has an instructable and web page about his homemade conductive glue (it was like a 2:1 ratio of black liquid electrical tape to graphite lubrication product); he noted that its resistance changed as it was bent and squeezed.

Both of these devices, once constructed, could be hooked up to the Arduino just like any resistor. Since there are six analog inputs, you have plenty to handle the fingers.

You could also try to find really small piezo elements; I am not sure on the interfacing of them to the Arduino (as a force sensor), but it would probably involve some kind of over-voltage protection circuitry, as piezo elements can generate fairly high voltage; but once again, they would interface to the analog ports. You would probably want to encase them under some extra cloth, perhaps inside of some RTV silicone glue, for shock protection (they are a little too fragile to use bare).

Handling the MIDI aspect should be possible as well; I also think I remember seeing a MIDI shield that somebody homebrewed somewhere…

There are plenty of options for the accelerometer/gyro; if I were you, I would look into using Lilypads and their associated boards. Since they are smaller in footprint than a regular Arduino, and are designed for wearable computing (which is what this glove device is, ultimately), it might be a better “fit”, so to speak. I think there is a LilyPad form accelerometer available, as well as a BT module. Otherwise, you are going to want the Arduino somewhere other than on the wrist, as the extra weight may cause discomfort over long usage periods; but that is something to be determined by testing, of course.

Sparkfun and plenty of other places sell accelerometers that are small and easy to interface to; most only require a few digital pins for serial communications (some use SPI, some use I2C, some just plain TTL serial). You’ll have plenty of pins available. One final thing: PNI Sensors has an interesting device to sense yaw/pitch/roll and other data from a sensor, but it works via USB - however, it should be possible to buy it from them without the USB components (it isn’t cheap, though - $99.00 for the USB version).

As far as your final question, I am not sure how to answer that, but if I am understanding your question - you are meaning whether you need individual dongles on the PC for each BT device, right? I am not too familiar with BT, but my gut feeling is you don’t; you just need the single adaptor on the PC (I think it is a master-slave node situation like USB; one master node, multiple slave nodes). Maybe someone else can clarify this portion of your question.

zoomkat:

Bare in mind that if what you want to do is cheap/easy, you would see many people making them.

I don’t think it has anything with it being difficult - these kinds of interfaces (glove interfaces) have been explored since the late 1980’s, if not before. I think it has more to do with the fact that it is a niche product, as well as a solution looking for a problem. Even in the heyday of virtual reality (mid 1990’s), there really weren’t that many glove devices available (the broad patents issued didn’t help, either); even now, with most of the patents expired, you don’t see many such devices on the market - the need for them just isn’t there currently. Hopefully this will change, but I am not betting on it happening anytime soon unless a breakthrough in HMD research occurs and we get a wide FOV with high-resolution displays on an HMD that doesn’t require you to mortgage your house (check out some of the HMDs from Kaiser-ElectroOptics - drool).

:slight_smile:

BTW - check this thread on the MIDI stuff:

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1222425476

:slight_smile: