hi Axel
this is the Richtek RT1025
an integrated sensor that includes two
Measure techniques
the first measurement technique is
electrocardiogram
basically measuring that electrical heart
pulse from your heartbeat in an
electrical way so you'll see the sensor
has two electrodes and basically these
electrodes can be used to measure your
electrical pulse of your heart the other
sensor that is on this board is PPG
it's a measurement that uses an LED
light that penetrates your skin and
measures the reflection from basically
the internal veins in your finger and
the blood circulation in your veins is
basically a sort of pulsing and by
measuring reflection during this
different blood circulation pausing you can also measure your heartbeat
but one interesting fact of this sensor is
that the two measurements combined
can also be used to make an estimation
of your blood pressure well let me show you how this works
this sensor
has the Bluetooth module basically it's a
this sensor has a Bluetooth module
on there so the RT1025 communicates with the
Bluetooth module
the raw data of the measurements is then via
the Bluetooth module transferred to
for example an app on your mobile phone
the mobile phone receives the raw data
does the manipulation of the data
and can extract the tooth wave forms
the top waveform here is the ECG waveform
and the bottom waveform is the PPG waveform
the measurement from your vein pulse a
pulsing blood circulation
and finally after this measurement
you can get your heart rate
and you can measure your blood pressure
let's first make a demonstration how this works
so I will activate the app
the app now is operating
and Axel please put your finger on the LED sensor
and put your under fingers on the electrodes
on the back
and hold it steady here you can already see
your heart pulse from your heart rate
so this is the electrical signal and it says it needs to have a stable waveform so keep it still
and you have to find finally a stable waveform for your PPG
as well
as soon as the software detects
stable waveforms for both readings it
now sees the heart pulse and a very stable
PPG waveform from this
from these two waveforms
you can calculate or estimate your blood pressure
and how is it done Basically if you look at
your veins your heart pulse is from your
heartbeat it's an electrical signal that
immediately travels through all your body the heart pulse
basically means your heart
is contracted and then the heart pushes the blood through your veins
to your fingers now when the
blood travels through your fingers it
will take some time and basically the
time it takes from the heart pulse to the
valley of a PPG wave form is a measure
of blood pressure high blood pressure
means that your blood travels very fast
and it basically results in a very short
PTT time low blood pressure means the
blood travels much slower and this
therefore it takes longer time from the
heart pulse to the PPG wave form so
basically in this waveform here you see
the heart pulse you see the PTT waveform
and the software has made a calculation
from this time to this time and thereby it makes an estimation of your blood
pressure high reading and low reading
and this measurement is quite convenient
because normally for blood pressure
You need to add a cuff at least you have to
measure and then reduce the pressure
and this is really not comfortable
not the measurement that you
can do that very often
this sensor can for example be used in applications
In this case we have a sensor with two
electrodes and the LED this sensor can
be worn across your chest and for
example people that have heart condition
can use this sensor to basically monitor
their heart rate and blood pressure
several times a today and the real
important thing with it is that when
there is a gradual change in blood pressure
this means there could be something
with your heart and that could be
an indication that you want to see
your doctor so these devices can be used as a
monitoring system for people that may
have a heart condition or want to be
warned of any change in
their blood pressure
another application
For example is this sport watch a
sport watch or maybe a sport watch
including a belt when you are exercising
and after you're exercising you would
like to measure your heart rate but
also your blood pressure it can be
implement even in just a single watch
the LED and the sensor the bottom
electrode will be connected to your wrist
and you can add two sensors on top of your watch
and these are basically measuring the ECG
pulse and again combining these two
signals you can even in sport watch get
a measurement of blood pressure
so how does this RT1025 work
you see here
this is the evaluation board circuit you have the biometric sensor
in here and the biometric sensor basically
consists of these two systems there are
actually three electrodes for measuring
your ECG the ECG two electrodes are used
to measure the differential signal but
because your body has a lot of
noise which is coming from the
environment there is a third electrode
that is used as the common mode
cancellation electrode so the common
mode cancellation electrode will remove
the body noise and thereby is able to
measure this extremely small
ECG pulse which is micro-level
the other sensor
are two LEDs and a photodiode
normally you will use one red LED and one IR LED
and by measuring by using the
IR and the red LED you can basically detect the difference
in blood circulation and you can even
make a measurement of your CO2
your oxygen level in your blood
so this PPG measurement is not only able
to measure heartbeat but even CO2
oxygen level by using different sensors
in this module
then you see on this board we have also added
an accelerometer
the RT3001 and RT3001 here
can be used for example in sports applications or applications where you
are moving a lot to make adjustments in
the sensor settings because if you're
moving a lot it could be very easily
influencing in these measurements and by
using an accelerometer input you can basically
provide offset and make these
measurements more accurately even when
you're moving around
here is because you need to also provide
power to all these modules and here is an example of the power management
solution that we provide the Bluetooth
module normally is powered because it
consumes very low energy
you can power this by an LDO the other sensors like
the accelerometer and the biometric sensor
they have different input voltages
for example they have a digital input
voltage and an i/o input voltage and these voltages
are normally using a buck
converter because they consume more
power so in order to conserve battery
life it's very important that you use
high efficiency converters for the high
current applications and thereby they
are saving you power another point is
that most of these applications will not
be continuously operating this sensor is
now switched off because it's not active
measuring and during the switch of time
all these circuits are basically
operating at a very low quiescent current
and even during the off time you want to
have good efficiency and therefore these
parts are using extremely low quiescent
current and these
converters are able to achieve about 90%
efficiency even in these standby modes
and thereby extending your battery life
also when the device is not used
so finally
Let me see
so Axel I hope it is an interesting application for you
This is a really interesting application
we will try to make a kit which includes an evaluation board and an app that we can provide to our customers
the customers can first see how it works and then they can try
to develop their own application inside
a sport watch application or a medical sensor board etc
thank you