Heart Rate Monitor Schematics and Source Code for the ATExpo 2007 EASi Line




For the second year in a row, we have designed the give-away hardware for the EASi Line demonstration at ATexpo. We would like to share with you the design, source code and binaries, so that those of you who are interested can learn, make modifications, or come up with some other useful purpose for the give-away. Essentially, what you received is a 4 digit display controlled by an Atmel Tiny2313 processor. The board also contains a differential amplifier, power supply, and various other electronics to detect a person's heart beat. The board is powered by a 9V battery and has an auto-off feature to power down after a conversion is complete.

If you like your pulse reader board, you decided to use our project files to make your own or derivative project, or just have a comment in general, please send us an e-mail and let us know!


Project Details
Board Specs Design Considerations
Heart Rate Monitor Schematics Heart Rate Monitor PCB Layout
Heart Rate Monitor Silk Screen Mechanical Layout
Parts List / Bill of Materials Instructions on how to use
Heart Rate Monitor Source Code Reprogramming
Further Resources & Disclaimer



Board Specs   [Back to Top]
Here are the specifications for the LED Readerboard.
  • Processor: Atmel ATTiny2313
  • Power Supply: 9V Battery.
  • Clock Speed: Internal 1 Mhz Oscillator
  • Minimum Power Requirements: 6.4V
  • Current Draw when On: ~ 120 mA
  • Current Draw when Off: 0.0001 mA
  • Programmable with Atmel AVR tools & AVR Studio 4.12 or higher
  • 6 Pin Program Header, Not included
  • Code: C Source Available
  • 4 digit LED display
  • Pushbutton On
  • Auto-Off
  • LM324 quad amplifier configured as a very sensitive differential amplifier


Design Considerations   [Back to Top]
The Heart Rate Monitor was designed to be a give-away at the Assembly Technology Expo, and therefore had to meet a number of requirements. The following is a short list of the project design goals:
  • Low cost
  • All components on one side of the board except the battery
  • Support for in-system programming
  • At least one or two through hole parts to demonstrate various equipment on the EASi Line
To keep the device even more useful, we added a few design contraints of our own:
  • Must draw very little or no current when off to extend battery life when not in use
  • With only one momentary push-button switch, system must be able to turn itself off after a period of time
  • Use common parts to help facilitate quick prototyping, and make purchasing for the show simple
What we ended up with is the design you'll find here.



Heart Rate Monitor Schematics   [Back to Top]
Page 1
Page 2
Page 3


Heart Rate Monitor PCB Layout   [Back to Top]
Front
Back


PCB Silk Screen   [Back to Top]
Front


Mechanical Layout   [Back to Top]


Parts List / Bill of Materials   [Back to Top]

35 Resistors

 

 

Quantity:

 

References

 

Value

 

Value2

 

Package

 

PartNum

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6

 

R1, R2, R9, R11, R33, R35

 

10K 5%

 

.1W

 

0603

 

ERJ-3GEYJ103V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

R3, R12

 

0 ohm

 

.1W

 

0603

 

ERJ-3GEY0R00V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6

 

R4, R6-R8, R10, R16

 

100K 5%

 

.1W

 

0603

 

ERJ-3GEYJ104V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

R5

 

4.7K 5%

 

.1W

 

0603

 

ERJ-3GEYJ472V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3

 

R13-R15

 

10M 5%

 

.1W

 

0603

 

ERJ-3GEYJ106V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8

 

R17-R24

 

120

 

.1W

 

0603

 

ERJ-3GEYJ121V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7

 

R25-R29, R32, R34

 

1K 5%

 

.1W

 

0603

 

ERJ-3GEYJ102V

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

R30

 

240 1%

 

.06W

 

0603

 

CRCW0603240RFKEA

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

R31

 

715 1%

 

.06W

 

0603

 

CRCW0603715RFKEA

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

21 Capacitors

 

 

Quantity:

 

References

 

Value

 

Value2

 

Package

 

PartNum

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

C1

 

470pf

 

50V

 

0603

 

ECJ-1VC1H471J

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

11

 

C2, C3, C8, C9, C13, C14, C17-C21

 

.1uf

 

50V

 

0603

 

C1608X7R1H104K

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6

 

C4-C7, C10, C11

 

10uf

 

25V

 

1210

 

GRM32DR61E106KA12L

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

C12

 

1uf

 

16V

 

0603

 

EMK107BJ105KA-TR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2

 

C15, C16

 

18pf

 

50V

 

0603

 

ECJ-1VC1H180J

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

3 Integrated Circuits

 

 

Quantity:

 

References

 

Value

 

Value2

 

Package

 

PartNum

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

U1

 

LM324DR

 

 

 

SO14

 

 LM324DR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

U2

 

ATTINY2313-20SU

 

 

 

SOP20.375

 

ATTINY2313-20SU

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

U3

 

LM317LDR2

 

 

 

SO8

 

LM317LDR2

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6 Transistors

 

 

Quantity:

 

References

 

Value

 

Value2

 

Package

 

PartNum

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

Q1

 

MMBT3904

 

 

 

SOT23_MMBT3904

 

MMBT3904DICT