MOD-EKG - Open Source Hardware Board
MOD-EKG - Open Source Hardware Board MOD-EKG - Open Source Hardware Board MOD-EKG - Open Source Hardware Board
Heart-Rate and EKG Monitor Using the MSP430FG439 development board
Price25.95 EUR
10 - 49 pcs23.36 EUR
50 - 10000 pcs20.76 EUR
In Stock


  • Based on Texas Instruments application note SLAA280a
  • MSP430FG439 microcontroller
  • LCD display
  • No additional electrodes required! Right and left hand board-mounted contact electrode plates – HR1 and HR2
  • Two status LEDs
  • Two user buttons
  • UEXT connector that allows easier connection to other boards
  • 3V CR2032 lithium battery onboard connector
  • 14-pin 0.1” step JTAG connector for direct microcontroller access via MSP430 debugger to debug the software or to power the board
  • A switch to alternate between “battery” and “UEXT” power supply
  • PCB: FR-4, 1.5 mm (0,062"), red soldermask, white silkscreen component print
  • Dimensions: (3.0 x 2.8)" ~ (76 x 71) mm


  • The readings seem wrong. I get only constant value displayed. The arrow in the middle of the display is not blinking. I tried powering the board with my JTAG debugger using the on-board JTAG connector and I also tried powering  the board from external 3.3V power supply using the UEXT pins. Tried different positions of jumpers and BAT/UEXT switch. What is wrong? Why the readings stay constant?
  • The source of the problem is the power supply. MOD-EKG is a sensitive board and glitches or noises power supply lines might affect the readings. Even if the USB ports and the power supply unit are of good quality, there is still parasitic capacitance between the human body and mains power line, which affects the readings. Be sure to test with a 3V battery - either insert a good CR2302 coin battery directly in the connector at the back of MOD-EKG or attach a 3V battery to pins #1 and #2 of the UEXT (2 batteries x 1.5V also do the job). If you wish to power the board from the JTAG or external power supply make sure there is galvanic isolation or good filtering between the power supply and the MOD-EKG board. For example, if you want to isolate your JTAG debugger from the mains power hum you can use our USB-ISO product (between the computer's USB port and the JTAG debugger).