Heart Rate Monitor Interface
(photo: Sparkfun)
New! : You can download a new
firmware package that returns the period (in milliseconds)
between pulses here.
The Heart Rate Monitor Interface (HRMI) is an intelligent
peripheral device that converts the ECG signal from
Polar Electro Heart Rate Monitor
transmitters into easy-to-use heart rate data. It
implements a sophisticated algorithm for computing an
average heart rate even with noisy or intermittent data
from the transmitter.
The HRMI was born from the Heart Rate
Telemetry system I designed. I wanted to do
something with the algorithm I had designed for that
product and pitched this product to Nathan
Seidle, Sparkfun CEO. He agreed with a handshake and
went off to layout the board for Sparkfun’s
manufacturing process. They build the board and I
provided the firmware, documentation and demo code. You
can buy one here.
Features
- Multiple interfaces: USB, Logic-level serial and I2C
- Dual heart rate processing algorithms: averaged and raw
- Uses the RMCM01 Polar OEM receiver
- Compatible with coded and non-coded Polar transmitters including T31, T31C, T61C and Wearlink®
- 32-entry heart rate data history buffer
- Four 8-bit ADC inputs
- Up to a 5 channel digital input/output utility port
- Simple command/response interface
- Programmable power-on default operation
- Custom exercise equipment
- Portable heart rate monitoring devices
- Bio-feedback devices
- Heart beat aware body-worn electronics