Friday, December 23, 2011
The device works reliably after replacement of battery although the instructions are easy to ignore. They didn't survive translation for me. It will log up to 30 hours with a variable interval for data collection making even longer tracking possible. Others have noted that the data can be exported to a CVS file for other uses. Kubios accepts such files but whether the data granularity would be acceptable is the issue.
Fine display of the printable data:
The 150 BPM is my exercise period followed by a cool down and three separate trips up and down 10 flights of stairs to deal with keys and locking myself out.of my apartment.
Wednesday, November 16, 2011
Phoenix Ambulatory Blood Pressure
Sub-project: Piezo Film Pulse Sensor
Sub-project: Piezo Film Pulse Sensor
Project DescriptionThe purpose of the piezo film pulse sensor project is to identify and build a reliable, low power, low cost blood flow sensor. The sensor is intended for two proposed designs for the ambulatory blood pressure monitor (ABPM). They are: (a) an oscillometric cuff design (as a Korotkoff sound sensor) and (b) the blood flow velocity design. The project includes the following deliverables:
- Selection of the piezo film sensing element(s).
- Design of a sensing circuit, including filtering and amplification stages.
- Layout and fabrication of a small, low noise circuit board.
- Bill of material
- Evaluation of the completed sensor system.
- Public invention disclosure and release.
- A written report.
Piezo Film Sensor ElementThe piezo film sensor element selected for this test was the SDT1-028K made by Measurement Specialties, Inc. It was selected because (a) it is very sensitive to low level mechanical movements, (b) it has an electrostatic shield located on both sides of the element (to minimize 50/60 Hz AC line interference), (c) it is responsive to low frequency movements in the 0.7 - 12 Hz range of interest, (d) the foil size was about right (1 inch / 2.54 cm long) and (e) it has an integral connector and cable for simple connections. The sensor is shown in Figure 1. An RG-174 BNC connector was attached to the opposite end of the cable (not shown).
Filter/Amplifier CircuitThe filter/amplifier circuit shown in Figure 2 was created for the piezo film sensor. It was specifically designed for battery powered operation from three AA or AAA cells (3.6 - 4.5 VDC), and consumes just 100 uA of current. The BNC connector located on the left side of the board connects to the piezo film sensor. The output is monitored with oscilloscope probe(s) via test points located on the board. The board dimensions are 2.5 inch (6.4 cm) x 3.8 inch (9.7 cm).
The circuit has a very high input impedance. Applications notes from Measurement Specialties, Inc. report that the low-end frequency response of the piezo film can be lowered from 5-6 Hz to 0.7 Hz by using a 10 Megohm or higher input impedance. The front end of the filter/amplifier circuit uses an op-amp follower in parallel with a 10 Megohm parallel resistor.
Complete documentation for the circuit is given here, including a schematic diagram, bill of material (BOM) and PCB artwork. All parts (except for the PCB artwork) can be ordered on-line from Digi-key Corporation at www.digi-key.com. The PCB artwork can be modified and ordered on-line from ExpressPCB at www.expresspcb.com. Just download their free CAD software and the board artwork file named PiezoAmp.pcb. The board conforms to the specifications for their low cost 'miniboard' service. The board assembly uses surface mounted components and can be hand assembled with the aide of a small soldering iron and a microscope.
Wrist Pulse ResponseThe piezo film was attached to the wrist with cloth athletic tape. The sensor was placed over the pulse point as shown in Figure 3. The adhesive on this tape is designed to be attached to the skin, and is breathable. It's a fairly weak adhesive which also allows the tape to be removed without damage to the piezo element.
Mid-arm ResponseThe piezo sensor was moved from the wrist to the mid forearm area. The response there was less dramatic as shown in Figure 6. In this case the piezo film is probably picking up the acoustic sound wave rather than any physical motion of the skin surface. This is an area that needs improvement because the acoustic sound waves are probably more valuable in the measurement system, because they permit simplified attachment to the skin.
Blood Velocity Response Between Elbow and WristTwo identical piezo film sensors and filter/amplifier circuits were configured as a non-invasive velocity type blood pressure monitor. The first sensor was located on the inner left elbow at the same location where Korotkoff sounds are monitored during traditional blood pressure measurements with a spygmometer. The second sensor was located on the left wrist as described above (about 12 inch / 30cm from each other). Figure 7 shows the results.
Phoenix patent references under the heading of Non-invasive Blood Pressure Monitors Using Pulse Velocity Methods. These can be found via the hotlinks located at the top of the same page. Several techniques are described in those patents including relative pulse delay, EKG to pressure pulse delay and pulse width.
One of the best patent references is Chen et. al, US Patent No. 6,599,251. Besides being an excellent summary of prior art in the field of non-invasive blood pressure measurement, Chen descripbes how blood pressure measurements are obtained using the pulse delay technique, as well as his data correlating pulse delay and pressure. However, Chen uses optoelectric sensors rather than the piezo film elements that are shown in this page. It is believed by the author that good, non-invasive blood pressure sensors using the techniques described on this page can be designed around Chen's claims.
ConclusionsThe data show that piezo film can simultaneously monitor two pulse signals located at a fixed distance from each other. This forms a two-point blood velocity monitor that can be adapted for the measurement of blood pressure. The data show that a 12 inch (30 cm) span results in a time lag of about 32 milliseconds.
The technique worked quite well, but does need improvement. Additional experimentation is needed. The following ideas have been generated by the Phoenix group:
- Use a smaller piezo element for improved signal-to-noise
- Use a piezo cable. It is hoped that this will improve the
sonic sensitivity (over the current sensitivity to mechanical
- Attenuate extraneous acoustic vibrations that are transmitted
up the cable. Layers of 'Silly-putty', 'fun-tak' and Sorbathane(tm)
are good candidates for sonic absorbing materials that could
be attached to the cable.
- Use an acoustic coupling compound (such as K-Y jelly) between
the skin and the piezo film element.
- A commercial varient of this product has been found at Tensys Medical (SanDiego,
CA). Also see US Patents 6,514,211; 6,228,034; 6,176,831.
About This PageThis page is maintained by David A. Skramsted. It was last updated on 19 September 2005.
The author(s) provide this information as a public service, and agree to place any novel and useful inventions disclosed herein into the public domain. They are not aware that this material infringes on the patent, copyright, trademark or trade secret rights of others. However, there is a possibility that such infringement may exist without their knowledge. The user assumes all responsibility for determining if this information infringes on the intellectual property rights of others before applying it to products or services.
(C) 2004-2005 Wade D. Peterson, David A. Skramsted and Daniel E. Glumac. Copying and distribution of this page is permitted in any medium, provided this notice is preserved.
Sunday, October 16, 2011
Tuesday, October 4, 2011
[For those interested, here is a link to a 20-page read-only PDF that provides an overview of much of what is included in the book.--OH]
From that PDF overview:
Sunday, September 18, 2011
This is the most powerful feedback tool I have experienced. It is a surprizing advance in a pursuit. The following text was posted earlier at QuantifiedSelf:
RE: suggestions for simple data vizualization tools?
Keep it simple and real time, except for long term trends on more complex questions or issues. Sonification of HRV is my target. Got interested before cardiac ablation resolved atrial fibrillation and continue exploring with a simple Polar monitor and attachments based upon the Polar Heart Rate Module - RMCM01.
SuperCollider programming is still developing, but my real-time heart beat in my ears turned out to be a terrific feedback instrument. Never much for exercise groups or formal equipment, going with the flow of the tick of my heartbeat lets me explore movement in new ways. Walking down the street now has dance elements woven into the internal visualization of body and mind state. Bliss is remarkably easy to recognize and propagate - shifts in attention are markers for a drifting state that is absorbing on many levels. Having this tool allows for lots of tiny experiments with interesing results.
This is a much smaller second version. The first had two AAA batteries. With 6 hours on the battery I'm considering slimming down the other unit. The other end of the plastic plumbing fitting can take a larger battery.
Wore a Polar Chest Transmitter and display watch to a dental appointment. Encouraged by a NuCalm System experience, noise isolating earbuds were used with the audio pulse unit. No science here, but I've had pain, panic, and problematic dentistry and relaxing was never this easy. I neared sleep twice. There was a mouth block disabling jaw movement witb a dam and local numbing for a root canal. Not bliss, but focused calm with a reminder pace.
Monday, July 4, 2011
OK, you need a few hints. Download the free .pdf, study the text and prosper.
So is guidance inb the exploration of the benefits of of mindfulness available for curious individuals? Yes.
But wait, there's more, a whole page of links to ebooks such as:
Long-Term Meditators Self-Induce high-Amplitude Gamma Synchrony
Thursday, June 23, 2011
less TV, more reading
less shopping, more outdoors
less clutter, more space
less rush, more slowness
less consuming, more creating
less junk, more real food
less busywork, more impact
less driving, more walking
less noise, more solitude
less focus on the future, more on the present
less work, more play
less worry, more smiles
Briefer Guide to Better Being:
Eat better, move more, avoid unhealthy substances and connect with others in healthy ways.
Briefest Guide to Better Being:
Smile, Breathe, Go Slowly, enjoy.
Briefer from http://5healthytowns.org/ , brief and briefest from http://zenhabits.net/
Sunday, June 19, 2011
Financial Times Article: Invasion of the Body Hackers
Monday, May 23, 2011
The Electricity of Touch: Detection and Measurement of Cardiac Energy Exchange Between People R. McCraty, M. Atkinson, D. Tomasino, W.A. Tiller In: K. H. Pribram, ed. Brain and Values: Is a Biological Science of Values Possible. Proceedings of the Fifth Appalachian Conference on Behavioral Neurodynamics. Mahwah, NJ: Lawrence Erlbaum Associates, Publishers, 1998: 359-379.
Friday, May 13, 2011
Mindfulness and Subjectivity.pdf
This never made it as a post but seems to fit perfectly:
Self-Determination and the Neurology of Mindfulness
Self-actualization is one of the keystones of humanistic psychology which, as a reaction to the reductionist values of behaviorism and psychoanalysis, also silently ignored brain research, subsuming it under the same rubric. Now comes mindfulness, a fairly new movement, with its openness to brain research and such cutting-edge notions as the adaptive unconscious—“thin slicing” unconscious perceptions for immediate decision making. The integration of mindfulness with emerging brain research leads to the possibility of modifying brain structure through conscious awareness, thereby restoring self-determination to its proper role. Another incipient movement in humanistic psychotherapy, deep empathy, is explained in terms of mindful human connection and limbic brain function. Just as emotion, thought, and brain structure mutually affect one another, so do therapist and client. Mindfulness, emotional connection, and deep empathy all contribute to mental well-being and a physiologically nurtured brain and help us transcend the numbing “consensus trance” that blinds us to the deeper aspects of life. Mindfulness and the new awareness of mind-brain interaction bring us back to the self-actualization values of the beginnings of humanistic psychology.
Thursday, May 12, 2011
Self-Determination and the Neurology of Mindfulness
Self-actualization is one of the keystones of humanistic psychology which, as a reaction to the reductionist values of behaviorism and psychoanalysis, also silently ignored brain research, subsuming it under the same rubric. Now comes mindfulness, a fairly new movement, with its openness to brain research and such cutting-edge notions as the adaptive unconscious—"thin slicing" unconscious perceptions for immediate decision making. The integration of mindfulness with emerging brain research leads to the possibility of modifying brain structure through conscious awareness, thereby restoring self-determination to its proper role. Another incipient movement in humanistic psychotherapy, deep empathy, is explained in terms of mindful human connection and limbic brain function. Just as emotion, thought, and brain structure mutually affect one another, so do therapist and client. Mindfulness, emotional connection, and deep empathy all contribute to mental well-being and a physiologically nurtured brain and help us transcend the numbing "consensus trance" that blinds us to the deeper aspects of life. Mindfulness and the new awareness of mind-brain interaction bring us back to the self-actualization values of the beginnings of humanistic psychology.
Wednesday, May 11, 2011
Discrete real-time sonification of heart rate variability is still intriguing especially as it might inform the interaction between individuals. This symphonic interplay of mother and fetal heartbeats crystalized that, but creating a meaningful shared information "display" - not there yet.
Steve, possessing significant audio knowledge and sharing content for life's little lessons contributed:
Auditory processing capability of brain, I believe, is more significant than documented to date.
In the link below, click on "animated display" of amount of brain mapped to vision, sound, and
integration of both together. Visual listening for humans, Audio vision for dolphins.
My fraternity brother was studying this at MIT early 1960's.
He demonstrated that we could hear up to 100 Khz by biting a stick and inserting it into a glass of water with a hydrophone emitting high frequency sound. It is now well known that nonlinearity of air propagation renders ultrasound frequencies beating together with sidebands separated by frequency differences of audible frequencies is easily audible.
That latter phenomenon is unrelated to the former. The former implies that our own hearing may have first developed early on when our ancestors lived in water. (and part of it is now "vestigial")
Tuesday, May 10, 2011
Monday, May 9, 2011
The screen shot shows one session's results. Real time feedback comes in a number of display choices,