Showing posts with label Circuit. Show all posts
Hardware update
Hardware update: From the breadboard to soldered circuit board
The group integrated the circuit with the arduino board and bluetooth by soldering.
The new circuit has a 9V power supply and the 9V is split to two, 6V for the bluetooth and 9 V for the arduino nano3.0
The new circuit gives a much more stable signal than the old one. The reason may be the 9V supply gives more stable voltage than USB does.
The group integrated the circuit with the arduino board and bluetooth by soldering.
The new circuit has a 9V power supply and the 9V is split to two, 6V for the bluetooth and 9 V for the arduino nano3.0
The new circuit gives a much more stable signal than the old one. The reason may be the 9V supply gives more stable voltage than USB does.
ECG: Circuit
ECG: Circuit
- Infrared emitter and detector
- 1 x 15ohm, 1 x 10kohm, 2x 100ohm, 1x 1kihm resistors
- 1 x 1uF, 2x 100uF, 1x 10uF capacitor
- 1 x 741 Op-Amp
IR Emitter
The group used a 15ohm resistor, to obtain a bright IR source without burning the emitter.
IR detector
The group use a IR detector to detector the IR reflect from the user body, with some tests the group found that fingers will give the best signal.
The group used a 10 kohm resistor, to prevent burning the IR detector
The group has tried not using any resistor and 15 ohm resistor, which end up burning the IR detector.
OPAPM
The signal received from the IR detector is too low for observe and calculation, so an amplify is needed for a readable signal.
The group used LM741 signal amplify from the ECE lab
Filtering
The signal received after amplify has a lot of noise that makes the data inaccurate, so a RC filter is designed to reduce the noise after amplify.
