A new device that allows a computer to change the user's emotional perception of reality.

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All augmented reality devices so far provide an interactive experience of the real-world environment that is enhanced by computer-generated perceptual information. In contrast, the EmotiGlass project explores ways in which a computer can modulate the user’s EMOTIONAL perception of reality. Our projects aims to develop the first “Modulated-Emotion Reality” device. EmotiGlass enables completely new applications in the field of augmented reality in which emotional biases can be manipulated by computer applications. Additionally, EmotiGlass has therapeutic applications as an aid to help control stress and anxiety.


By: David Prutchi and Jason Meyers

All augmented reality devices so far provide an interactive experience of the real-world environment that is enhanced by computer-generated perceptual information.  In contrast, the EmotiGlass project explores ways in which a computer can modulate the user’s EMOTIONAL perception of reality.  Our projects aims to develop the first “Modulated-Emotion Reality” device.  EmotiGlass enables completely new applications in the field of augmented reality in which emotional biases can be manipulated by computer applications. Additionally, EmotiGlass has therapeutic applications as an aid to help control stress and anxiety.


Does the sight of a dog make you happy or fearful?  Are you comfortable around people of other races?  We commonly think that the emotions aroused by events around us are the results of our biases and prior experiences.  This is very true, but there is much more than meets the eye when it comes to understanding the way in which our brains attach emotional content to our perceptions.

We develop implantable cardiac medical devices for a living, and a few months ago, we came across an interesting journal article that caught our curiosity.  In this paper [Azevedo, et al. 2017], researchers from the University of London and their colleagues showed that presenting an image at different periods of the cardiac cycle would cause changes in the way that subjects would emotionally perceive that image.

The paper reported that racial biases could clearly be modulated by changing the timing at which an image is presented.  In this study, pictures of dark-skinned or light-skinned individuals holding various objects were presented to coincide with either the heart’s contraction (cardiac systole) or relaxation (diastole).  Results showed that if the image was presented during cardiac systole, subjects significantly misidentified innocuous objects as weapons when they were held by dark-skinned people.  Remarkable!

A group from University College London conducted a related study [Gray, et al., 2009] through which they found that sensory processing depends on when stimuli are experienced in relation to heartbeat timing.  Specifically, the perception of pain – which is strongly biased by emotion—varied depending on when during the cardiac cycle noxious stimuli were delivered to the subjects.

The mechanism behind these effects seems to be that the emotional arousal caused by a stimulus depends on signals being received by the brain from the body’s internal blood pressure sensors (baroreceptors).  Simply timing the delivery of stimuli against the cardiac cycle can change the way in which the brain processes stimuli!

It’s not only the timing component of a stimulus that can change the emotions that it arouses.  The spatial component also has major effects on the emotional perception of visual scenes.  In his exciting book “Of Two Minds: The Revolutionary Science of Dual-Brain Psychology”, Dr. Fredric Schiffer [1998], a Professor of Psychiatry at Harvard Medical School and Attending Psychiatrist at McLean Hospital, showed that very distinct emotions can be evoked by selectively blocking access of the visual field to one of the brain’s hemispheres.

Spatio-temporal changes in the visual field also cause deep changes in emotional response.  EMDR (Eye Movement Desensitization and Reprocessing) is a known psychotherapy technique whereby causing side-to-side eye movements is believed to unlock a memory mechanism that can be used to reprocess traumatic events.  Outside the therapeutic setting, mild side-to-side sweeping of the visual field appear to decrease the emotional impact of distressing events. The objective of the EmotiGlass project is to develop a pair of active glasses that can be controlled to selectively...

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Emotiglass Electrical Source

Electrical source files (Schematics and PCB layouts, including libraries) in Altium format. Also includes PCAD ASCII format.

x-zip-compressed - 2.79 MB - 10/16/2018 at 05:22


EmotiGlass Mechanical source files

Mechanical source file in Solidworks assembly format containing all 3d printed parts. Also includes STEP and Parasolid formats.

x-zip-compressed - 33.34 MB - 10/16/2018 at 04:47


emotiglass STLs

STL files for all 3d printed parts

x-zip-compressed - 45.01 MB - 10/16/2018 at 04:33


Wiring info r1-1 draft.pdf

PCB Wire to Board Header Pinouts and wiring instructions (draft)

Adobe Portable Document Format - 507.89 kB - 10/11/2018 at 23:00


PCB drawings and assembly notes r1-1 draft.pdf

PCB Layout drawings and assembly notes (draft)

Adobe Portable Document Format - 705.16 kB - 10/11/2018 at 22:59


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  • 2 × DS1, DS2 DOGM128E-6 High-contrast, 128x64 pixel LCD supertwist display
  • 2 × Left/Right Liquid-Crystal Shutters Small Liquid Crystal Light Valve - Controllable Shutter Glass, Adafruit Product number 3627
  • 1 × R6 22k
  • 1 × R7 100k trimmer
  • 4 × R1 - R4 10k trimmer potentiometers with shaft

View all 15 components

  • PCBs Received and Assembled

    Jason Meyers2 days ago 0 comments

    We received our PCBs from Osh Park and assembled 2 complete sets (one set, complete with the exception of one display, is shown above).  Details about the build follow.

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  • Mechanical Design Complete

    Jason Meyers2 days ago 0 comments

    The CAD model for the EmotiGlass frame has been completed, and the printers are now busy making our prototype a reality.  Provisions for mounting the PCB stack and LiPo battery were added to the previously printed frame design.  The mounting arrangements for the side pieces were also changed to integrate with the mounting for the additional components.  The side pieces were also updated with the feedback from the human fit test. 

    In addition to the 3 major frame pieces, 2 additional small parts were modeled.  One is the key which will be glued onto the pulse sensor connector so that it cannot be inserted backwards, the other is just a spacer for the board stack (the mating distance is an odd size (~4.2mm) for which spacers are not available off the shelf.)

    STL files for all parts have been uploaded.  Screenshots below show the other side of the full assembly and individual views of the components.

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  • Mechanical Design Update – Human Fit Test

    Jason Meyers5 days ago 0 comments

    While the previous test prints had determined the fit of the major components into the EmotiGlass frame, the equally important fit of the frame onto a human head had not yet been fully tested.  Also, the exact position of the battery and electronics stack had yet to be finalized.  To allow progress, an initial design for the side pieces (temporarily omitting mounting provisions for the electronics) was modeled and printed.  This allowed the frame to be positioned on a human head and various aspects evaluated.  The following conclusions were generated which will be implemented in the next few days:

    -The placement of the displays is slightly below center of the eyes.  This is desirable, as it allows for adjustability.  I plan to design and 3d print spacers to clip onto the bridge (possibly, in more than one size) to allow the positioning to be easily adjusted to different noses.

    -The shape of the arms works well but could be improved by extending them further back and down slightly.

    -There appears to be space to mount the electronics stack and batteries directly between the side shutters and the ear, and elevating them as previously planned won’t be necessary.  (these will be stood off slightly so that even if they do overlap with the ears they won’t interfere).

    I'm hoping to complete the CAD model and 3d print the final frame in the next few days, which will be an exciting milestone.

  • ​ Wearable Prototype Schematics and PCB Layouts Finalized

    Jason Meyers5 days ago 0 comments

    We’ve been making a lot of exciting progress towards the completion of the wearable prototype design.  The wearable prototype schematics have been finalized at revision 1.1, which has been uploaded.  The only major change in this revision is the removal of the potentiometers used for control, as the GUI has advanced to the point where they have been deprecated.

    The wearable prototype breaks the circuitry into 4 small PCBs:

    The right side pcb mounts to the frame and provides a termination point for all of the wiring going to the other boards and to the components which don’t mount directly to a PCB (side shutters and battery).  The feather plugs into this board, which contains a fuse on the battery input and a soft power switch.  It also contains a socket for the pulse sensor to plug into, which was intentionally selected and oriented so that it will easily disconnect if the wire is accidentally pulled.  The shape of this board was driven by the feather, so there was extra space which was filled with prototyping area to facilitate rework or feature addition in the future.

    The right front and left front PCBs contain the capacitors needed for operating the LCD displays.  The right side also contains the light sensor for the auto darkening function.

    The right side dev PCB contains the hardware LCD drivers.  These will be replaced by firmware, eventually, which is why they are on a separate PCB.  This PCB will stack on top of the feather.

    Layout of these 4 PCBs has been completed, and they have been submitted to OSH Park for manufacturing.  The gerber zips and a draft of a pdf with layout prints and assembly annotations have been uploaded (this will be updated after we assemble our initial batch).  We’ve selected the largest surface mount packages available for ICs (mostly SOIC’s) and are using 0603 passives (with plenty of space between them) so that the boards will be reasonable to assemble with only a basic soldering iron. 

    The boards are designed to be directly wired to each other.  A number of interconnect options were considered, but this ended up being the simplest and lowest profile option.  While it will be time consuming to assemble, this is acceptable for a few prototypes.  30 awg wire wrap wire will be used for most signals.  Wire with Kynar or Teflon insulation is highly recommended.  Power and ground will use something slightly larger, probably 26 awg.  A draft of the wiring diagram has been uploaded (this will be updated with any changes we make during initial assembly).

    Lastly, a draft BOM which contains only the electronic components has been uploaded.  This will be updated to include the mechanical components shortly.

  • New EmotiGlass GUI Prototype Running

    David Prutchi10/07/2018 at 13:54 0 comments

    Thanks to the great Greg Leonberg who knows how to code HTML/JavaScript, we now have a nice, intuitive GUI to control EmotiGlass via BLE.  We are still cleaning the firmware and GUI.  We'll post source as soon as we are done.

    For now, this is a screen shot of the GUI running on the mini iPad under EvoThings:

  • Prototype GUI running under Evothings Studio

    David Prutchi09/28/2018 at 01:43 0 comments

    Just got a prototype BLE GUI for EmotiGlass running under Evothings Studio 2.2.1.  The iOS Evothings player is CGTek 1.0.6.

  • Wearable Prototype Progress: First Print

    Jason Meyers09/17/2018 at 23:09 0 comments

    The CAD model for the wearable prototype has progressed, and a first rev of the main frame piece has been printed.  The frame is being designed with the front and 2 sides as separate parts.  This allows the front piece which holds the glass LCD displays and shutters to be printed from a stiff plastic (PLA for now, but I may eventually switch to a CPE family material so I don't have to worry about leaving the print in a hot car), allowing it to provide the most protection possible to the glass.  At the same time, the sides can be printed from a more flexible material from the Nylon family, which will allow the Emotiglass prototype to fit on heads of different sizes (hopefully) without being uncomfortable.

    As soon as I completed the model for the front frame piece, I wanted to print it because I was expecting to need to make some adjustments to the fit.  This part takes about 11 hours using a .4mm nozzle in an Ultimaker 2+.  Sticking to this smaller sized nozzle makes it possible to remove the support material without too much hassle.   After clearing the support and a few minutes of filing, I was able to test the fit of the components:

    The fit on the display and shutter came out very well for a first test, needing adjustments of less than a millimeter.  The fit on a face, on the other hand, wasn't as good.  We tried holding the part on a few different faces, and concluded that the bridge needed to move down significantly.  Additionally, I've flattened out the area above the bridge in the hopes that that may improve comport:

    As the second rev prints, focus shifts back to the PCB layouts.  The initial outlines are transferred from this model into Altium for PCB layout to see how everything fits.  There is room to extend the PCBs downward somewhat, so they'll be adjusted as needed.  The PCB shapes are shown in purple in the following image.  2 screws (not shown in the model) will secure the boards.  The holes are sized to support either imperial or metric hardware - a #2x1/4" or M2x6.  The holes are sized for standard (cheap) machine or sheet metal screws.

    With the front cad close to done, focus will shift back to the electronics.  I'll swing back to the cad model and finish the sides after the boards are ordered.

  • Wearable Prototype Schematics and Simplifying the Hardware Design

    Jason Meyers08/27/2018 at 06:18 0 comments

    The schematics for the wearable prototype have been uploaded, with each sheet corresponding to a small PCB with a portion of the EmotiGlass circuitry.  Sheet 1 shows the right side PCB, which makes the connections between the Feather and the rest of the system.  Sheets 2 and 3 are the front PCBs, which mount to the front LCD displays.  They contain the support components necessary for the LCD Displays, connections for the side LCD shutters, and connections to other parts of the system.  Sheet 4 shows the development PCB, which contains the control pots and hardware PWM circuitry.  This board will be mounted on top of the feather, which is mounted on top of the right side PCB.

    Currently, the side LCD shutters are driven by a dedicated hardware PWM circuit.  DC will degrade the shutters over time, so they must be driven by a circuit with no net DC.  A standard PWM peripheral is not able to do this, but it appears that the TCC modules (Timer/Counter for Control) in the Atmel SAMD21 processors (the ARM Cortex M0+ based microcontroller used by this feather) will be able to generate balanced PWM drive signals with no external circuitry.  The firmware module for this will be written while we are waiting for PCBs to be manufactured. 

    The control pots are present primarily for convenience during prototyping.  As development advances, their function will be replaced eventually by software.  For this reason, the pots and the hardware PWM circuitry have been placed on a separate board.  This board can be installed for initial work with the wearable prototype, and then removed once the firmware and software have advanced sufficiently.

    The completed wearable prototype schematics allow work on the PCB layouts to proceed together with the mechanical design of the frame, which is currently partially complete.

  • Short videos of EmotiGlass breadboard prototype in operation

    David Prutchi08/23/2018 at 21:00 0 comments

    Following are three short videos showing the basic functionality of the EmotiGlass breadboard prototype.

    We added some backlighting (using a strip of EL material) to show the way in which the device causes selective occlusion.  The user's eyes would be on the side of the EL material looking at the scene through the liquid-crystal panels.

    First is the breadboard operating in Baroreceptor-Synchronized Occlusion mode:

    The pulse sensor is on Jason's finger.  We can control the occlusion pattern as well as the timing of the occlusion versus the plethysmographic signal.

    Next is the breadboard being controlled to produce a window for lateralized brain stimulation (we are showing functionality of controls, rather than actual occlusion that would be used for lateralized stimulation):

    Lastly, the sunglasses mode (David casts a shadow on the light sensor):

  • Wearable Prototype Plan and Mechanical Design Start

    Jason Meyers08/22/2018 at 22:58 0 comments

    With the breadboard operational, the next step is to develop a wearable prototype.  Our plan is to 3D-print a frame with a shape similar to traditional glasses which will hold all of the components while being (reasonably) comfortable to wear.  The LCD displays and shutters will fit into grooves in the frame which will capture them on 3 sides.  The front LCD displays will each be mounted to a small PCB which will then attach to the frame with 2 screws, securing those displays in place.  The side LCD shutters will be retained by a small bracket.  A carrier PCB for the Feather PCB will be mounted above the right ear, and the battery will be mounted above the left ear. 

    Before modeling the frame, it was necessary to develop CAD models of the major components.  The LCD display and LCD shutter models were built using the datasheets (where possible) and plenty of measurements of the actual components.  The board outline for the Feather was exported from Eagle, and blocks representing keepout zones for the larger board components were added from measurements. 

    A 3D guide sketch for the glasses was developed based on measurements of my face and of a pair of cheap sunglasses which were a giveaway at last year’s Maker Faire.  This is only a starting point, as it will probably take a few iterations to make the shape and size feel comfortable.  The major components were arranged on the guide sketch so that modeling of the frame could begin.

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