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Heart rate Detector and alarm circut 1

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isabellemiceli17

isabellemiceli17

Electrical
May 2, 2017
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I am working with Behind The Wheel Technology to create a steering wheel cover that detects the drivers heart rate and will send an alarm to wake them up before they start to fall asleep.

I am am trying to put EEG/ECG/EMG electrode heart rate monitors and wire it to an "if...then" code somehow which will then trigger an alarm to sound. Our studies have found that there is a stage called microsleep where the heart rate drops 8% and our goal is to detect this drop and hope to prevent car crashes all over the nation.
Please let me know if you have any input or could give us an estimate as how much something like this could possibly cost to put together.
 
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> embedded electrodes seem to me to be problematic; how would your system deal with gloved drivers or drivers with only one hand on the wheel?

> have you considered using eye blink instead, as that requires no physical contact with the driver?

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I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
 
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We have thought of eye blink technology and are not entirely against that idea however there are a few competitors already using that technology.
The reason why we believe electrodes are preferred is because they are small enough that if you do only have one hand on the wheel, then your fingers will be able to complete the circuit.
Gloves we are not as concerned about because our primary target is for truck drivers who drive 8-14 hours a day and they are typically not wearing gloves.
 
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I have been (very occasionally) using exercise machines that monitor heart rate by means of stainless steel contact strips on the handles. They work okay if you firmly grasp both handles, not so well if you only grasp one. Most of that small sample seem to have one 'dead' handle.
... and there is clearly a time delay of several seconds in the circuit, so that changes are reflected, but late, and letting go of the handle does not immediately cause the displayed value to go to zero.

I think you might get some pushback about a requirement to grasp a piece of cold metal in wintertime.

I recall reading that someone is monitoring driver alertness by sensing small motions of the steering wheel, which happen continuously when the driver is alert, and not when (s)he dozes off.


Mike Halloran
Pembroke Pines, FL, USA
 
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Those stainless steel pieces were actually our number one choice for quite a while but then we realized the delay and accuracy. We have also considered technology similar to that in fitbit. That however uses light and we do not want to distract the driver of course.

I am not sure if the cold is one of our concerns because typically they are diving for a while and that allows the car and steering wheel to heat up.
Is there a type of coating of some sort that could go over the metal pieces and possibly protect it from the extreme cold?
 
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Cold is only really likely to be a worry if the contacts are bulky enough to have significant thermal inertia - and there's no real reason for you to make them that way.

A.
 
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I think that someone on your team needs to start fleshing out what hardware is needed and use something like Digikey to get prices.

Have you confirmed that a single hand will get you the data? You're essentially completing the circuit across 2 fingers, and ECG typically requires a path that goes at least close to the heart.

Another option besides the Fitbit heart rate approach, which uses green LEDs, is the pulse oximeter approach, which uses red and infrared LEDs. Pulse oximeters are typically used primarily to measure blood oxygen, but in the course of getting there, you also get heart rate. Since you don't need the accuracy, you might be able to move the red LED wavelength to where they're nearly imperceptible, or use only the infrared LED, but you'll need to do some testing. If the red LED is required, you might be able to push the wavelength up past 750 nm, at which the eye response is pretty low. With some decent shielding, the light might not even be apparent to the driver.
Oxy_and_Deoxy_Hemoglobin_Near-Infrared_absorption_spectra.png




TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
 
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Do you have any evidence that heart rate changes significantly and quickly when going from "sleepy" to daydreaming/dozing? I doubt it. Then nothing else matters.
 
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We are familiar with pulse oximeters and are currently using them as part of our MVP. We are using the oximeters that clip on fingers and it have a digital display screen to tell us the numbers so needless to say we are a little unfamiliar with how exactly to manipulate the wavelength and/or infrared LED.

 
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There's some literature that suggests it could work:

Nevertheless, the cueing does seem tenuous, at best. We looked into the eye-blink about 20 yrs ago, which seemed to be the most promising at the time.

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert! faq731-376 forum1529 Entire Forum list
 
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Mercedes Benz offers 'Attention Assist' which illuminates a Coffee Cup icon in the dash when the system notices that the driver is getting tired.

According to Richard Hammond formerly of Top Gear, the system monitors 70-some parameters, a larger number of data channels than when he was in Intensive Care after his jet car crash.

As far as I know, it relies on existing sensors and data.
 
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I commend your efforts to increase road safety.

IR based heart rate monitors are probably not the best solution. I think they need to be clipped onto a finger to work well. I built one as part of a course in university and neither myself nor any of my classmates were able to make it tolerate much variance in finger placement or pressure.
 
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How do the sensors on exercise machines sense the heartbeat? Change in resistance, or maybe capacitance between the hands as the heart beats?
 
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If anyone here has an interest in measuring their heart rate download AD8232 data sheet, it goes into great detail. There are assembled boards with this chip everywhere for a low as $7 shipped.
 
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You are not actually building something. The purpose of these exercises, as with all education, is the learning of how to research a problem and find information on your own. A simple google search on ebay and google of "AD8232" would have provided all the information needed. You have only cheated yourself.
 
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