iSmartch Smartwatch Technology Guide: A Comprehensive Guide to Functionality And More

Detailed Explanation:

Steps

Steps are displayed on the firmware interface, can be read from the broadcast protocol and SDK/API. The number of steps captured in the broadcast package is real-time data for the day.

The daily maximum is 65535 steps.

• At 0 o’clock every day, the number of steps is cleared.
• Store for 7 days (cyclic coverage), reset to 0 at 12 o’clock every day, we store 2 bytes of data MAX= 65535 every hour, we store a 2bytes data every hour.
• Data storage density: 7*24*2bytes.

Sleep

Sleep data (deep sleep and light sleep will be read by SDK/API. Support data acquisition in broadcast protocol will be passed to Bluetooth base station or any Bluetooth scanning device.

• Default time: 10 pm – 8 am.
• Sleep data will be stored for 7 days (cycle coverage 7 days as a cycle). Such as 1-7 /2-8 /3-9.
• Data is stored every 15 minutes, each data is half a byte, one hour is 2 bytes.
• If the customer needs nap data, it needs to be specifically stated, we will match the firmware version.
• Data storage density: 7*24 hours*4 data (half a byte 1 data/2 bytes).

Heart Rate

Dynamic heart rate, ultra-low power consumption and accuracy, support broadcast protocol reading, support SDK/API APP reading.

PPG green light module

The measurement accuracy is 5bpm, 10bpm, and 15bpm. In comparison with the POLAR heart rate band or arm heart rate band (Wahoo), in multiple people and groups, and various scenes: static, living scenes, regular sports (such as running and walking), and irregular sports.

1. The accuracy is about 93% compared with the heart rate band in the case of 5bpm.
2. The accuracy is about 96% compared with the heart rate band in the case of 10bpm.
3. It’s basically the same as the heart rate band in the case of 15bpm.
4. Currently, the default is to continuously measure and broadcast data once every 250ms (the highest frequency can broadcast every 100MS), and the sampling frequency is defaulted to 25HZ.
5. Currently, the accuracy can be close to the heart rate arm band in the case of 5bpm, as long as there is no light leakage during testing.
6. If it is worn on the arm, the effect is better, faster follow-up, closer to the arm band.
7. The static heart rate is accurate, almost the same as the heart rate band, compared directly with the blood oxygen clip (please see the test video).
8. The heart rate LED should go out after a few seconds in the air (if it still flickers, it means there is a hardware problem).
9. Currently, heart rate detection cannot do live body detection. When the heart rate LED is facing a colored object, there will be a heart rate. Currently, due to industry technical issues, it has not been resolved, but most of the bracelets are placed on the side after wearing the strap, so this problem will not occur.
10. Using activity intensity can make wearing judgments. If a person’s activity intensity is 0 for several minutes in a row, it is judged that there is no wear, and the heart rate value is invalid.
11. Please see the detailed explanation of activity intensity or refer to the firmware analysis document for a specific explanation.
12. Incorrect wearing and measurement:
    • First: Multiple wristbands are worn on one hand, squeezing blood vessels, and colliding with each other.
    • Second: Leakage of light at the wrist, not fitting.
    • Third: The test of dynamic heart rate must be compared with the heart rate band.
    • Fourth: Measure the dynamic heart rate with red light (in red light mode, when the arm moves, the heart rate and blood oxygen are inaccurate, refer to the activity intensity for judgment). The dynamic heart rate should be measured with green light.

Blood Oxygen

Blood Oxygen (SPO2) Measurement Using Red and Infrared Light via PPG (also outputs static heart rate at the same time)

• Green light cannot be used for SPO2 measurement; it has to be red light (with infrared light also turned on)
• It’s displayed on the firmware and read by the app through broadcast protocols and SDK/API
• Blood oxygen measurement must be conducted when at rest, as it’s inaccurate when moving. Moreover, blood oxygen measurement is affected by the temperature of the arm, and different people have different blood circulation, causing different signal strengths. Therefore, the initial time value ranges from 15 seconds to 2 minutes. If the oxygen level can’t be measured within 2 minutes, please wear it again and ensure the measurement is taken at the position of three fingers from the wrist joint.
• The power consumption of blood oxygen measurement is quite high, approximately 800uA, so please pay attention to the usage methods:
  • Measurement can be timed by sending instructions from the base station (supported by some firmware)
  • Can measure one-time (enter the menu)
  • It supports Monitoring mode (long press touch under the blood oxygen interface). Entering M mode means that blood oxygen is continuously output on any page.
  • The default sampling rate is 25HZ
  • One-time measurement will only be made under the corresponding interface, and M mode will measure on any interface, whether it is one-time measurement or M mode, it is continuous measurement.

• Note: Determining whether the blood oxygen value is accurate

  • First: Measurements in low-oxygen environments (such as altitudes of 4,000-5,000 meters or above)
  • Second: Ensure quietness. If judging quietness, we have an activity flag in our broadcast protocol to judge whether it’s in a quiet state. There’s no UI interaction prompt on the bracelet
  • Third: At present, it’s basically on par with blood oxygen clips, and performs well in low oxygen environments (it has been tested on the plateau with blood oxygen values below 80, at altitudes of about 4,000 meters or above)
  • Fourth: Comparison reference — fingertip blood oxygen clip (please refer to the comparison video)

• Tips:

  • Generally, people with lighter skin can get results faster
  • People with good blood circulation can get results faster
  • People with moist skin can get results faster
  • Older people get results slower
  • The quality of the signal can be reduced for early results
  • The normal blood oxygen level for an individual is 95-99
  • If the blood oxygen level is less than 95 and there’s no lack of oxygen or it’s not in a high-altitude area, it’s incorrect. Possible reasons:
  • Indeed, there’s a lack of oxygen, which can be tested by holding your breath
  • There’s exercise, and the activity intensity is greater than 5 (there’s in the broadcast data), the blood oxygen value is not credible (Of course, software can also be made to prevent output if the activity intensity is greater than 5, but we haven’t done that yet — this is an interaction affair. After the oxygen level drops, customers need to check the activity intensity to make a comprehensive judgment. We actually haven’t done this process, leaving it to the customers. But customers might not understand, thinking there’s a problem — please pay attention to this.)
  • Currently, the algorithm can get the blood oxygen value down to 80, which is the lowest to 80. This is a requirement from customers for low oxygen testing, especially for those going to high-altitude areas and those who really need to detect hypoxia. This is where the blood oxygen indicator is truly useful.

• Testing principles and precautions:

  • Environmental temperature: When the environmental temperature is low, the capillaries shrink and the perfusion of human blood decreases. From the signal level, the human blood oxygen signal becomes weaker. Since the logic of the blood oxygen algorithm requires true blood oxygen, it requires a high signal, which will cause the output time to be prolonged or the accuracy to drop.
  • Limb movements: Currently, all blood oxygen solutions on the market are for static blood oxygen data collection. During testing, if there are limb movements or speech, etc., it will interfere with the blood oxygen signal, which is one of the reasons for the prolonged output time and decreased accuracy of blood oxygen.
  • Wearing position: The recommended blood oxygen test position is a finger’s distance above the wrist joint (about 2CM). The blood vessels are concentrated at this position, which is beneficial for the collection of blood oxygen signals. If the wearing position is changed, it may cause abnormal sampling data or the collected blood oxygen signal is weak. The bracelet will not prompt if the wearing position is incorrect.
  • Individual differences: The strength of each person’s physiological signal varies. For people with weaker signal strength, the output time and accuracy of blood oxygen are worse than those with stronger signal strength. Individual differences are also unavoidable. (For example, people who are relatively white or thin have a signal value much worse than ordinary people.)

• Market analysis:

  • False blood oxygen, green light outputs blood oxygen, this is obviously wrong
  • False blood oxygen, added a few red lights, but it’s still false blood oxygen, no PD for blood oxygen acceptance
  • True blood oxygen chip + false value algorithm, if it comes out within 10 seconds, it’s likely to be false. Some strategies are to output a value to the user at a fixed time, such as 25 seconds/30 seconds, until the true blood oxygen value comes out. If it doesn’t come out, maintain the false value — this can be directly tested on the plateau. Because the plateau is low in oxygen, it can’t be simulated by algorithms.
  • True blood oxygen chip + blood oxygen algorithm + wider card range (PPG signal quality), this outputs values faster, but the accuracy is lower.

True blood oxygen chip + blood oxygen algorithm + narrow card value (PPG signal quality), that is, the signal must be in place to output, otherwise it won’t output. We currently adopt the fifth type.

Temperature range from 35-42 degrees Celsius

• When <35 degrees Celsius, display Lo
• When > 42 degrees Celsius, display Hi
• High thermal conductivity temperature sensor with built-in algorithm for continuous measurement of wrist surface temperature, with a measurement range of 35 degrees Celsius -42 degrees Celsius, and an accuracy of ±0.1 degrees Celsius.
• The body temperature algorithm is based on surface temperature measurement + algorithm modification. If the customer thinks our body temperature algorithm is inaccurate, we provide the original data of the surface temperature, and the customer can develop their own algorithm.
• Both body temperature and surface temperature can be output simultaneously in the broadcast protocol (supported by some firmware versions)
• For the above algorithms, please refer to the documents on body temperature and surface temperature.

HRV/RRI (Heart Rate Variability and R-R Interval)

Medical or health management or psychological analysis

• Displayed in firmware and read by apps via broadcast protocols and SDK/API
• 2 bytes (within 65535 for 2 bytes)
• Typical applications: biofeedback, stress measurement
• Output: HRV is continuously output for 24 hours when the green light is on, there is HRV as long as there is green light
• HRV is also available in red light mode, but we believe the green light mode is more accurate

Respiratory rate

• Unit: times/minute
• Displayed in firmware and read by broadcast protocols (The normal breathing rate of a person is a quarter of the heart rate)

Stress level (psychological stress)

• Output range: 0-255
• The higher the value, the greater the stress. Please stay calm during measurement, the value is not accurate during exercise.
• During quiet times, we calculate the stress value by calculating the cumulative value of HRV over a period of time. Because the current system resources are limited, we run a relatively small model in the firmware. If the customer thinks the accuracy is not high enough, they can collect the original value of HRV and calculate it on the APP side or cloud side using a larger model.
• 0-30 – very calm
• 30-50 calm
• 50-70 moderate anxiety
• 70 or above – anxious

Blood pressure

• Limited accuracy, for customers to choose and use with caution.

Social Distance

• An alarm will be issued when the same bracelet is close to each other
• Used in factories, etc. as a means of epidemic prevention

Distance setting

• Can be set to 1.5 meters/2 meters/3 meters in the firmware menu
• If the customer is not satisfied with the distance setting, they can adjust the RSSI value using our provided Bluetooth protocol, which represents the approximate distance
• This design is based on Bluetooth RSSI calculation, the distance will not be particularly accurate, because Bluetooth does not have diffraction capabilities, it is easily affected by blockages, if customers need a more accurate ranging solution, please contact us for further communication, we have other solutions that can do more accurate measurements.

Contact History

• Stores contact IDs for 24 hours
• The project should not exceed 255 MAX = 255
• Contact ID MAC addresses (for proximity with the same bracelet)
• Time should be synced first
• Data will be cleared once a day at 12:00 PM
• This means that everyone should sync data every day, otherwise data will be lost
• The next update will increase storage space, including richer information such as contact ID, contact time, contact distance, etc., for customers to generate contact history
• If the ID of the contact person is reported in real-time within the range of the Bluetooth gateway, the platform can be used for storage, regardless of whether the bracelet has stored the contact history data internally

SOS(Press and hold for 5 seconds, press and hold for 5 seconds to turn off)

• This function is mainly used in several aspects. For example, it can connect with a mobile phone, and press and hold for 5 seconds in an emergency. After receiving this message, it can be pushed to the background and then pushed to the emergency contact, sending the location. Because in an emergency, it’s slower and less covert to take out the phone and make a call.
• In addition, when you press SOS, the SOS BIT position in the frequency band broadcast protocol will be 1, lasting for 1 minute. In an environment with a Bluetooth base station, it can be transmitted to the background after being received by the base station, and the management personnel can see it and take corresponding actions, such as in schools, smart factories, etc.

Fatigue Monitoring

• According to the quality of sleep, heart rate, body movement, etc. the previous day, input the fatigue algorithm. The algorithm gives the result at 8 o’clock the next morning, and the data is cleared at 19 o’clock in the afternoon.
• The data does not change in real time, and this value is updated once a day.
• The lower the value, the more fatigued, and vice versa.

PPG Raw Data Collection

• This DATA must be obtained in a connected state. For getting PPG RAW DATA, please refer to the documentation
• Currently supports up to 500HZ PPG original value sampling
• Default sampling rate: 25HZ up to 500HZ (Bluetooth command parameter setting or SDK has API to set)
• Currently, PPG data is not stored locally. If storage is needed, customization is required
• PPG data can collect green light raw data or red light raw data
• First: Manually switch the user to the red light menu (oxygen saturation) or open the red light through the SDK/or Bluetooth protocol (if you want any interface to be red light, you can switch to the oxygen saturation interface and open the MONITOR mode)
• Second: The SDK interface or the command of the Bluetooth protocol is used to open the acquisition of PPG data, and it can be accepted directly.

Sensor Raw Data (Acceleration Gyroscope Geomagnetism Raw Data)

• Gsensor X Y Z raw data–
• Gyroscope sensor X Y Z raw data (customization required)
• Geomagnetic sensor raw data (customization required)
• The sampling rate is 25Hz, and data collection needs to be connected.
• The maximum sampling rate can reach 200HZ, which requires customization
• XYZ and gyroscope data are not stored. If storage is needed, customization is required.

About Storage and Data Access:

• 7days Steps 7*24hour*1data(2bytes for MAX=65535)
• 7 days of sleep data 7*24*4data (We have 4 data per hour, each data has 4BITrepresent intensity)
• Heart rate: Store 7 days*24 hours*4. Every 15 minutes one data
• SPO2: Store 7 days*24 hours*4 Every 15 minutes one data
• Body temperature: Store 7 days*24 hours*4 Every 15 minutes one data
• Respiration rate: Calculated by heart rate
• Blood pressure: Store 7 days*24 hours*4 Every 15 minutes one data

Monitor Mode

• Long press to enter the green light Monitor mode under the heart rate page. In any interface (except the oxygen saturation red light interface), the green light is always on. The data that can be obtained at the same time are: Exercise, heart rate, body temperature, respiration, stress value, blood pressure, cannot obtain oxygen saturation
• The heart rate is static heart rate + dynamic heart rate (automatically recognized)
• Long press to enter the red light Monitor mode under the oxygen saturation page. In any interface (except the green light interface), the red light is always on. The data that can be obtained at the same time are: Exercise, heart rate, body temperature, respiration, stress value, blood pressure, heart rate
• The heart rate is a static heart rate (if it is not accurate when moving, the heart rate obtained by the red light PPG is a static heart rate, and the accuracy can be judged by the intensity of the activity. If the intensity of the activity exceeds 5, the oxygen saturation value is considered unusable)
• Note: Some projects have removed the Monitor mode in some firmware versions. Please communicate with the factory for specifics.

Activity Intensity (Based on the XYZ three-axis acceleration algorithm to get the value)

• Supports 0-240 activity intensity, updates one value every minute. This protocol does not give a serial number. The serial number is aligned in the business layer. Please ensure that the bracelet time is correct before use (Call the AC interface to broadcast time, let the bracelet automatically adjust time)
• For example, the intensity value of the algorithm accumulated in 1 minute from 12:02:01 to 12:02:59 is output: the algorithm accumulated value of the intensity value from 12:01:01 to 12:01:59, and this value is continuously output
• High-intensity physical activity: ≥ 120
• Moderate-intensity physical activity: ≥ 100
• Low-intensity physical activity: 50 < X <100
• Sitting or napping: 0 < X <50
• Deep sleep: 0 < X <25
• Light sleep: 25 < X <50
• The bracelet is still: ≤1

Historical Data (the bracelet’s time must be accurate for the historical data to be discussed)

• The historical data is kept for different days under different data dimensions according to different firmware versions. Generally speaking, sports/sleep/heart rate/body (surface) temperature/etc. are kept for 7 days, a value is collected every 15 minutes, and it is saved for 24 hours (please refer to the description of each data dimension for details)
• The data is saved to FLASH one hour after collection. Customers need to sync the time and wait at least one hour before they can get historical data.
• The data dimension is 7 days*24 hours*4 (4 data per hour), including heart rate/oxygen saturation/body temperature/blood pressure data
• If a bracelet starts to be worn without time calibration, the historical data starts to be recorded from May 1, 2021 (for example, it was used for 3 days). Of course, after the bracelet is calibrated for time, the first record is recorded as the current date, but the data for the 3 days starting from May 1, 2021 still exists, but it is meaningless. We only recommend supporting historical data after time calibration. It is not recommended to support data storage without time calibration, so if you use the APP for collection, you will also get inaccurate historical data.
• Ways to obtain historical data:
  • Obtain it through the SDK. Use the APP to call the SDK function to obtain historical data.
  • The broadcast content will not contain historical data (broadcasts are real-time data)
  • Use a base station to connect to a certain bracelet to obtain historical data (this is not commonly used in most cases and is not currently available)
  • If historical data needs to be transferred to the cloud platform, customers need to obtain the data on the APP side and upload it to their own cloud platform
  • For the overlap of historical data and real-time data in time, customers need to make judgments on the business side. This can be done by time stamp.
• If the bracelet time is correct, and it is used for 3 days, and then the power is off (the user does not charge under the condition of low battery), then after recharging, the time is restored to after May 1, 2021, the storage of historical data is as follows:
  • If you sync historical data at this time, you can get the historical data before power loss, such as the data used for 3 days and 8 hours.
  • If the user does not calibrate the time, for example, it has been used for 8 hours, it will be recorded as the 8-hour data starting from May 1, 2021.
  • If the user syncs the time after using it for 8 hours, then the time goes back to the current time and starts recording, but the 8-hour data starting from May 1, 2021 still exists, and it can still be obtained through the historical data interface.
  • Generally speaking, all data is saved.
  • 7-day storage – cyclic storage

Almost all bracelets support NFC M1 13.56M TAG

• Some bracelets with metal surfaces do not support it, such as I10/SH06.
• Support passive NFC (dozens of card readers have been tested so far)
• Before customers ship, they need to specify the card reader for family interaction verification to avoid frequency offset or coil mismatch. Some card readers are made for cards or mobile phones. The coil is large and cannot match the small coil of the bracelet.
• Please do not ask the bracelet to adjust the coil induction area (the bracelet structure is limited), so under normal circumstances, use the card reader to adapt to the bracelet.
• The bracelet coil can be adjusted for frequency (for example, there is a frequency offset for a certain card reader) or power (number of turns of the coil).
• Before shipment, it needs to be confirmed with iSmarch about the card reader (needs to be demonstrated at the sample stage, and the card reader needs to be used as the factory inspection standard for shipment)
• If the card reader cannot read, there are several possible reasons
  • The frequency of the card reader is off
  • The power of the card reader is not enough
  • The coil of the card reader is too large (it used to match the card) and does not match the bracelet, so it may only be swiped at a certain position.
  • The customer needs a CPU card (needs customization, it’s a protocol issue)
  • For the first three situations mentioned above, the card reader must be adjusted to adapt to the bracelet. The structure of the bracelet has already limited it, the coil is fixed, and the only thing that the bracelet can adjust is the fourth point. If the protocol does not match, it is necessary to change the NFC IC.

Skipping Rope and Ball Hitting

• Developed for the needs of kindergartens and some schools
• Support skipping rope count (requires specific firmware support)
• Support ball hitting count (requires specific firmware support)
• Currently, only two projects, SH09 and C1, are supported, and only one version of the firmware is supported. If the customer does not choose this version of the firmware, code migration and redevelopment are required. If other projects need this function, they need to be redeveloped.