Analog Device’s AD8232 is an integrated signal conditioning block for ECG and other biopotential measurement applications. It is designed to extract, amplify, and filter small biopotential signals in the presence of noisy conditions, such as those created by motion or remote electrode placement. This design allows for an ultralow power analog-to-digital converter or an embedded microcontroller to acquire the output signal easily.
The device can implement a two-pole high-pass filter for eliminating motion artifacts and the electrode half-cell potential. This filter is tightly coupled with the instrumentation architecture of the amplifier to allow both large gain and high-pass filtering in a single stage. An uncommitted operational amplifier enables the creation of a three-pole low-pass filter to remove additional noise. The user can select the frequency cutoff of all filters to suit different types of applications. [via]
Single-lead Heart Rate Monitor Analog Front End - [Link]
Scott W Harden writes:
I re-vamped my DIY ECG project. This new project is fully documented and uses extremely common and cheap parts, all of which could be purchased at RadioShack. It serves at both an ECG *and* a pulse oximeter, depending on which leads are attached. It uses a single chip (LM324, a quad operational amplifier) with a virtual ground to eliminate the need for a negative voltage. As a pulse oximeter with a 12V supply it outputs clean 10V swings when pulses occur. It’s intentionally unsophisticated, and made to be easy to replicate by anyone interested in electronics. Although you could view its output on an oscilloscope, it’s designed to be output into a PC sound card for recording (if attenuated to microphone levels). I even describe how to spectrally process the data on the computer to clean it up, downsample it, and graph it in Excel or with a Python script.
Simple DIY ECG + Pulse Oximeter - [Link]
Imec demonstrated a low-power (20µW), intra-cardiac signal processing chip for the detection of ventricular fibrillation at this week’s International Solid State Circuits Conference (ISSCC 2013) in San Francisco with Olympus. An important step toward next-generation Cardiac Resynchronization Therapy solutions, the new chip delivers innovative signal processing functionalities and consumes only 20µW when all channels are active, enabling the miniaturization of implantable devices. [via]
Robust and accurate heart rate monitoring of the right and left ventricles and the right atrium is essential for implantable devices used in cardiac resynchronization therapy, and accurate motion sensor and thoracic impedance measurements to analyze intrathoracic fluid are critical for improving clinical research and analysis of intracardiac rhythm. Extremely low power consumption is also necessary to reduce the size of cardiac implants and improve the patient’s quality of life.
Carry a Chip in your Heart - [Link]
Pittsford, NY: imPulse(tm) is a personal, iPhone-compatible, handheld ECG Touch Monitor that will be introduced at this year’s Electronica Show in Munich, Germany, designed using unique EPIC touch sensors. Created by the sensorʼs manufacturer Plessey Semiconductors, imPulse(tm) is aimed at the home health market, and will allow the routine, quick and accurate recording of ECG signals outside of the medical environment – without the need for conductive gel or skin preparation. Read the rest of this entry »
Saelig Co. Inc. announces the availability of the PS25203 EPIC Sensor (Electric Potential Integrated Circuit) for a wide range of contactless ECG and movement sensing in automotive applications, including driver fatigue monitoring and seat occupancy. The EPIC sensor is a completely new, award winning, patent-protected sensor that can rapidly measure electric potential sources such as electrophysiological signals or spatial electric fields.
The EPIC Sensor revolutionizes the way movement sensing, medical ECG/EEG/EOG, proximity non-touch switching, or even gesture recognition signals are taken in vehicles. It can be used as a dry contact ECG sensor without the need for potentially dangerous low impedance circuits across the heart. By detecting changes in the electric field, the EPIC sensor can also drive a relay to act as a simple non-touch electric switch. The EPIC sensor can be employed in a proximity mode or to detect specific kinds of movement as a gesture recognition device.
PS25203 EPIC Sensor – For Low-cost Automotive Detection Systems - [Link]
Holst Centre, imec and DELTA announce an innovative body patch that integrates an ultra-low power electrocardiogram (ECG) chip and a Bluetooth Low Energy (BLE) radio. This unique combination fuses power-efficient electronics and standardized communication, opening new perspectives for long-term monitoring in health, wellness and medical applications. The system integrates components from Holst Centre and imec’s R&D programs. It is designed in collaboration with DELTA and integrated in DELTA’s ePatch platform.
The ECG patch measures up to 3 lead ECG signals, tissue-contact impedance and includes a 3D-accelerometer for physical activity monitoring. The data are processed and analyzed locally, and relevant events and information are transmitted through Bluetooth Low Energy. The patch is capable of monitoring, processing and communication on a minimal energy budget. When computing and transmitting the heart rate, the entire system consumes a mere 280µA at 2.1V, running continuously for one month on a 200mAh Li-Po battery. When transmitting accelerometer data (at 32Hz) on top of the heart rate, the power consumption remains below 1mA in continuous operation, giving about 1 week of autonomy.
Innovative technology for an ECG patch - [Link]
Pittsford, NY: Saelig Co. Inc. announces the availability of the EPIC Sensor (Electric Potential Integrated Circuit) – a new, innovative and disruptive electric field sensor. This completely new sensor technology measures electric field changes without requiring physical or resistive contact. EPIC is an award winning, patent-protected sensor that can rapidly measure electric potential sources such as electrophysiological signals or spatial electric fields.
The EPIC Sensor will revolutionize the way medical ECG/EEG/EOG, movement sensing, proximity non-touch switching, or even gesture recognition signals are taken in medical and sports instruments, toys, electric appliances, smart lighting, gaming, and security. The electrode surface of the detector is coated with a passivated thin dielectric for direct application to a test surface (such as human skin) without the need for electrically conductive gel. It can be used as a dry contact ECG sensor without the need for potentially dangerous low impedance circuits across the heart. By detecting changes in the electric field, the EPIC sensor can also drive a relay to act as a simple non-touch electric switch. The EPIC sensor can be employed in a proximity mode or to detect specific kinds of movement as a gesture recognition device. As the EPIC sensor does not need line of sight, it can even detect movement through solid walls, and can also be used to replace, or as an adjunct to, passive infra-red (PIR) sensors in a variety of applications including security motion detectors. Read the rest of this entry »
It’s time for a lecture. I’ve been spending a lot of time creating a DIY dlectrocardiogram and it produces fairly noisy signals. I’ve spent some time and effort researching the best ways to clean-up these signals, and the results are incredibly useful! Therefore, I’ve decided to lightly document these results in a blog entry.
Here’s an example of my magic! I take a noisy recording and turn it into a beautiful trace. See the example figure with the blue traces. How is this possible? Well I’ll explain it for you. Mostly, it boils down to eliminating excess high-frequency sine waves which are in the original recording due to electromagnetic noise. A major source of noise can be from the alternating current passing through wires traveling through the walls of your house or building. My original ECG circuit was highly susceptible to this kind of interference, but my improved ECG circuit eliminates most of this noise. However, noise is still in the trace (see the figure to the left), and it needed to be removed.
Signal Filtering with Python - [Link]
There are many times where you would like to “stabilize” an input signal so that you don’t see the input value “jumping” so much. This is specially true on the MilliVolt Signal range, where nearby noise present can disturb the original signal. In this case, you always have the option of buying some kind of signal conditioner, which handles the filtering function of the raw signal. However, there are many times where the noise problem presents itself after the system is built, in which case a simple software solution is preferable to mitigate the problem.
Simple Software Filter - [Link]
Temporary tattoos fitted with electronics make flexible, ultrathin sensors. [via]
Modern methods of measuring the body’s activty, such as electroencephalography (EEG), electrocardiography (ECG), and electromyography (EMG), use electrical signals to measure changes in brain, heart, and muscle activity, respectively. Unfortunately, they rely on bulky and uncomfortable electrodes that are mounted using adhesive tape and conductive gel—or even needles. Because of this, these types of measurements are limited to research and hospital settings and typically used over short periods of time because the contacts can irritate skin.
These limitations may be at an end, however. New research published in Science describes technology that allows electrical measurements (and other measurements, such as temperature and strain) using ultra-thin polymers with embedded circuit elements. These devices connect to skin without adhesives, are practically unnoticeable, and can even be attached via temporary tattoo.
Temporary tattoos fitted with electronics make flexible, ultrathin sensors - [Link]