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
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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
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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
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Heart Rate Monitor PCB Layout
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| Front | Back |
PCB Silk Screen
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| Front |
Mechanical Layout
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Parts List / Bill of Materials
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35 Resistors
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Quantity:
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References
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Value
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Value2
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Package
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PartNum
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6
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R1, R2,
R9, R11, R33, R35
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10K 5%
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.1W
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0603
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ERJ-3GEYJ103V
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2
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R3, R12
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0 ohm
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.1W
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0603
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ERJ-3GEY0R00V
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6
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R4,
R6-R8, R10, R16
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100K 5%
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.1W
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0603
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ERJ-3GEYJ104V
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1
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R5
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4.7K 5%
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.1W
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0603
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ERJ-3GEYJ472V
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3
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R13-R15
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10M 5%
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.1W
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0603
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ERJ-3GEYJ106V
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8
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R17-R24
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120
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.1W
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0603
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ERJ-3GEYJ121V
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7
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R25-R29,
R32, R34
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1K 5%
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.1W
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0603
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ERJ-3GEYJ102V
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1
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R30
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240 1%
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.06W
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0603
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CRCW0603240RFKEA
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1
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R31
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715 1%
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.06W
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0603
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CRCW0603715RFKEA
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21 Capacitors
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Quantity:
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Value
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Value2
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PartNum
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1
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C1
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470pf
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50V
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0603
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ECJ-1VC1H471J
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11
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C2, C3,
C8, C9, C13, C14, C17-C21
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.1uf
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50V
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0603
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C1608X7R1H104K
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6
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C4-C7,
C10, C11
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10uf
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25V
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1210
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GRM32DR61E106KA12L
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1
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C12
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1uf
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16V
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0603
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EMK107BJ105KA-TR
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2
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C15, C16
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18pf
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50V
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0603
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ECJ-1VC1H180J
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3 Integrated Circuits
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Quantity:
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Value
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Value2
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PartNum
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1
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U1
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LM324DR
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SO14
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LM324DR
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1
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U2
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ATTINY2313-20SU
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SOP20.375
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ATTINY2313-20SU
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1
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U3
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LM317LDR2
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SO8
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LM317LDR2
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6 Transistors
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Quantity:
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References
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Value
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Value2
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Package
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PartNum
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1
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Q1
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MMBT3904
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SOT23_MMBT3904
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MMBT3904DICT
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