Grove ear Clip Heart Rate Sensor
Introduction Grove ear Clip Heart Rate Sensor:
Heart rate ear clip kit contain a ear clip and a receiver module. The heart rate measure kit can be used to monitor heart rate of patient and athlete. The result can be displayed on a screen via the serial port and can be saved for analysis. The entire system has a high sensitivity, low power consumption and is very portable.
Inside the sound sensor, there is something called a diaphragm plate. When sound vibrations from speaking, clapping or other loud noises are produced, they hit the diaphragm plate, causing it to vibrate. When it vibrates, it changes the capacitance, which causes the voltage to change.Description. Sound sensor is used to receive acoustic wave and display the vibration image of sound. It has a build-in capacitively electret microphone that is sensitive to sound. The electret fil min microphone vibrates with the acoustic wave resulting in the change of capacitance and the subsequent micro voltage.
Spceifications:
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Battery Exclude Voltage: 3V-5.25V, 5.0V
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Work current: 6.5mA
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Wide power supply range: 3.5V
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Length of ear clip wire: 120cm
Circuit Operation:
In order for this to work you have to have skin contact, hence why AliveCor recommends using alcohol to allow the electric current bypass the issue of the pet’s fur. PetPace and Voyce do not advertise how they measure heartbeat but due to the fact that it is on the neck it must measure heartbeat through light. Technology, such as the apple watch and other devices worn on the wrist (or dogs neck), shine light into your skin to detect the difference in volume in blood that occurs when your heart beats and pushes blood through these vessels. Sensors on the device can detect how much light is reflected back which is less when there is a higher volume of blood. This way of measuring heartbeat is called photoplethysmography. To combat the fur getting in the way PetPace has sticking out probes to get close enough to the skin so that the light can reach the skin: ochie!In the device I wanted to make I did not want it to be uncomfatable to dogs through probes worn on the neck like PetPace and Voyce, or alcohol gel like AliveCor. Therefore I chose to do it via photoplethysmography and through an area on the dog that does not have much (or much fur!): the ear.As I wanted a low priced solution I chose to build the device through Arduino (Genuino Uno) board which cost approximately £14.40 (€20).
Arduino is an open source microcontroller that is programmable through Arduino Software (IUD). The photoplethysmography device I chose a Grove Ear Clip Sensor with receiver module from SeedStudio (cost around £10/€13.40). To pair these devices together I used standard Arduino wires: 10mm male jump wires. To ensure more accuracy I ran the Arduino board off a 9v battery connected via a battery connector (snap connector). The software I decided to use was also from SeedStudo written by FrankieChu (shown below). Unlike the code shown I did not use the base shield and instead wired it straight into the board. Authough the code allows for it, I also did not use LEDs & Breadboard to create a flashing LED representing heart rate. Instead I used the Serial Monitor (available under tools) to create an average heart rate per every 20 beats taken.This project works by measuring each heartbeat through photoplethysmography (as described above) and then creating a signal interruption when the blood volume is at its fullest. The IUD then times these interruptions (beats) to create an average interruption per minute. If using the LED, these interruptions also cause Arduino to change the state from LOW to HIGH causing a pulse flash.
I initially used it on the edge of my dog’s ears in a similar fashion to my own when building the monitor. However due to the furriness of the edge of my dog’s ear the light could not penetrate through this with the monitor restarting itself due to lack of signal. To combat this I then clipped the ear monitor to the middle by folding over his ear where there was no fur.(Disclaimer: This did not hurt him and the ear clip is not tight (I tried it myself). He actually fell asleep while I was doing this ). In the serial monitor this produced both the interruptions times (in milliseconds), total time (ms), beat number (out of 20) and average heartbeat; for my Dog his heart rate was 63 .
Once it was established you are able to take a dogs heart beat through their ears, I realized this method was not viable to be used in ordinary circumstances as the dogs ear was not in a normal position. I then tried other places on a dog’s body, including the inside of his leg which has not only high concentrations of veins but also is not very furry. I was able to get readings here, but they were not as reliable as the inside of the ear. This was because the average number of beats had greater variations; the rate would jump from 60 to in the 100s within 20 beats. A dog’s heart rate usually varies from 60 to 140 bmp (as you can tell from the above heartbeat (a low 63) he was sleeping). The variation was suspect due to the dog moving his leg causing interruptions altering the average time between the interruptions which are how the heartbeat is calculated.
I have found out it is possible to measure a dogs heartbeat through a cheap photoplethysmography device built using Arduino (approx £25 spent). However this is not possible in ordinary movement due to the dense fur usually found on a dog preventing photoplenthysmographies light transmission. Without shaving the dog, which we do not want to do, or constantly folding the dog’s ear over, which would be uncomfortable whilst standing due to the ear naturally flopping down in this breed, I am unsure how you would measure heartbeat. This is perhaps why current technology requires prongs into the dog or alcoholic gel.
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How the Grove ear Clip Heart Rate Senso Work:
With the current technology not supporting ECG or photoplethysmography, the alternative option could be though breathing monitoring which is directly linked to heart rate. As some dogs wear a dog harness already, a monitoring device could be put into place in a similar fashion and measure the breath rate. However in dogs with one of their primary senses being smell, this could cause interruptive data, or smell data? We shall have to see!The electrical monitors consist of two elements: a monitor/transmitter, which is worn on a chest strap, and a receiver. When a heartbeat is detected, a radio signal is transmitted, which the receiver uses todisplay/determine the current heart rate.An optical heart rate sensor measures pulse waves, which are changes in the volume of a blood vessel that occur when the heart pumps blood. Pulse waves are detected by measuring the change in volume using an optical sensor and green LED.A type of Heart Rate Monitor consists of an electronic circuit that monitors heartbeat by clipping onto a finger tip. It does this by shining light into or through your finger and measuring how much light is reflected or absorbed.
The Heartbeat rate information knowing is very useful while doing exercise, studying, etc. But, the heartbeat rate can be complicated to calculate. To overcome this problem, the pulse sensor or heartbeat sensor is used. This is a plug & play sensor mainly designed for Arduino board which can be used by makers, students, developers, artists who can utilize the heartbeat information into their projects. This sensor uses an easy optical pulse sensor along with amplification & cancellation of noise to make a circuit. By using this circuit, we can get fast and reliable heartbeat readings. This circuit can be operated with 4mA current and 5V voltage to use in mobile applications.The pulse sensor working principle is very simple. This sensor has two surfaces, on the first surface, the light-emitting diode & ambient light sensor is connected. Similarly, on the second surface, the circuit is connected which is accountable for the noise cancellation& amplification.The LED is located above a vein in a human body like ear tip or fingertip, however, it must be located on top of a layer directly. Once the LED is located on the vein, then the LED starts emitting light. Once the heart is pumping, then there will be a flow of blood within the veins. So if we check the blood flow, then we can check the heart rates also.
If the blood flow is sensed then the ambient light sensor will receive more light as they will be reproduced by the flow of blood. This small change within obtained light can be examined over time to decide our pulse rates.This sensor used in straight forward, however connecting it in the correct way matters. Because all types of electronic components are directly exposed to the sensor. So, it is mandatory to envelop this sensor by using hot glue, vinyl strip otherwise other types of non-conductive materials.These sensors cannot be operated with wet hands. The sensor’s smooth side must be located on the pinnacle of the vein & press it. Generally, Velcro tapes or clips are utilized to get this force.This sensor can be used by connecting it to the Arduino board. Once it is connected, then give the power supply with the help of VCC pin and GND pins. The operating voltage of this sensor is +5V or 3.3V. Once the sensor is connected to the development board such as Arduino, then we can use the readily accessible Arduino code to make things easier. Please refer to Arduino site for interfacing of Arduino with pulse sensor and its coding.
Frequently Asked Questions
What is the aim of the heartbeat sensor?
Heart beat sensors are designed to give digital output heart beat when a finger is placed on it. When the heart beat detector starts working, the light emitting detector (LED) blinks simultaneously for every heartbeat.
What is a pulse rate measurement circuit?
A type of Heartbeat Measurement Device consists of an electronic circuit that monitors heartbeat by clipping onto a finger tip. It does this by shining light through your finger and measuring how much light is absorbed. This goes up and down as blood is pumped through your finger.
What is heart sound sensor?
The heart sound sensing device is placed and arranged whereby the diaphragm is in contact with the body surface area of the patient, and the cable means is connected to the medical diagnostic device to accomplish a diagnostic heart sound analysis procedure.
How to measure heart rate?
To check your pulse at your wrist, place two fingers between the bone and the tendon over your radial artery — which is located on the thumb side of your wrist. When you feel your pulse, count the number of beats in 15 seconds. Multiply this number by four to calculate your beats per minute.
How do audio sensors work?
A sound sensor detects sound waves and converts them into electrical signals. It combines a microphone and processing circuitry on a small board. It measures sound intensity and produces a digital output signal using a microphone and LM393 level comparator chip.
