SparkFun will be closing on Monday for Memorial Day (5/28). Orders placed after 2pm MT on Friday (5/25) will process and ship out on Tuesday (5/29).
This is a wonderful evaluation board cooperatively designed by danjuliodesigns and SparkFun. The Heart Rate Monitor Interface (HRMI) is an intelligent peripheral device that converts the ECG signal from the Polar Heart Rate Monitor (HRM) 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.
Note: This product is a collaboration with Dan Julio. A portion of each sales goes back to them for product support and continued development.
1 of 1 found this helpful:
To test the Polar Heart Rate Monitor with a computer’s serial terminal, you would just follow the instructions listed in the manual . By following the instructions on page 13 http://danjuliodesigns.com/sparkfun/hrmi_assets/hrmi.pdf of the manual under the section “Quick Test with Host Computer,” I was able to send and receive data between the Polar Heart Rate and my computer’s serial terminal (with the settings 9600, 8-none-1-none and turning on the local echo). The green status LED was on when connecting to the sensor. There should already be a solder jumper on SJ1. The board’s Rx and Tx LEDs blinked momentarily when connected just like a normal FTDI IC.
By typing “G1” and providing a carriage return (hit the enter button on your keyboard), I was able to see a response on the serial terminal. This is the command for getting heart rate data as stated on page 23 of the manual. The output from the known good in tech support is similar to this:
3 118 0 0 0
The value is not always the same.
This skill defines how difficult the soldering is on a particular product. It might be a couple simple solder joints, or require special reflow tools.
Skill Level: Noob - Some basic soldering is required, but it is limited to a just a few pins, basic through-hole soldering, and couple (if any) polarized components. A basic soldering iron is all you should need.
See all skill levels
If a board needs code or communicates somehow, you're going to need to know how to program or interface with it. The programming skill is all about communication and code.
Skill Level: Competent - The toolchain for programming is a bit more complex and will examples may not be explicitly provided for you. You will be required to have a fundamental knowledge of programming and be required to provide your own code. You may need to modify existing libraries or code to work with your specific hardware. Sensor and hardware interfaces will be SPI or I2C.
See all skill levels
If it requires power, you need to know how much, what all the pins do, and how to hook it up. You may need to reference datasheets, schematics, and know the ins and outs of electronics.
Skill Level: Competent - You will be required to reference a datasheet or schematic to know how to use a component. Your knowledge of a datasheet will only require basic features like power requirements, pinouts, or communications type. Also, you may need a power supply that?s greater than 12V or more than 1A worth of current.
See all skill levels
Based on 4 ratings:
2 of 2 found this helpful:
In addition to working on humans, the Polar T31 transmitter can be strapped to a cow. We hung this interface on a steel bar about 2 feet from the cow with the transmitter, and it picked up the signal just fine (after we slathered some electrolytic gel on the transmitter). The data was collected by a simple serial program running on Ubuntu which sent a “G” command about once a second. If this pickup can work in a barn, it can pretty much work anywhere.
I used this device to get my heart rate to be displayed on two neopixle strips on my bicycle. The device was easy to use and I was up and running in a mater of minutes. The orientation of the device to the chest strap is important to get a robust signal. All my buddies got a kick out of this.
Easy installation. Plug in a usb cable (install FTDI Virtual COM Port Driver (VCP)), open serial terminal, type G1<enter> and you get the latest heart rate.
Remove solder jumper on SJ1, add solder jumper on OP0 and you can communicate via I2C (address 127 by default)
Only glitch I can replicate every time is by moving the sender out of range from the receiver. The values go berserk after that until I do a power recycle.
I attached the HRM to a Chromebook (Linux Mint 18 Cinnamon 64-bit) through the USB port. I observed the system log to get the device name (/dev/ttyUSB0) and used minicom 2.7 to verify that I send commands to the HRM and get data back from the HRM. I wrote Python code to periodically query the HRM and log the heart rate data and then tested it during an hour-long session on a treadmill. It worked great and the data was similar to the HR data shown on the treadmill. The whole experience took about three hours get to HR data. Next step is to optimize the code, add features to the code and understand the HR algorithm better. It was a challenging exercise and a good project for a beginner like me!