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Step 7Build and Program circuit for sigh detection. Assemble electronics into carrying case.
Follow the circuit diagram below. A higher resolution PDF is also attached.
Program the Arduino with the provided code.
To monitor breathing, we will be making a chest strap that is outfitted with a stretch sensor. The expansion and contraction of the chest will provide us with data that we can use, in code, to extrapolate what normal breathing is, and therefore determine with a larger than usual inhalation (followed by large exhalation) is. A 10 or 20K potentiometer will be used to dial in a threshold value, which will represent how large of an inhalation is associated with a sigh.
I purchased my stretch sensor from Merlin Robotics, a company in the UK. They stock a variety of sizes. I'm using the 20cm sensor.
In my circuit, i'm amplifying the signal from the sensor with a resistor bridge and an OpAmp chip (see diagram). This is the method suggested by the manufacturer. You can find the datasheet on the internet. Note: I imagine a similar idea could be done with pressure sensor instead of a stretch sensor. You'd could attach the pressure point on the sensor to some kind of tubing and wrap that tubing around the chest.
Drill holes in the front face of the carrying case and attach the potentiometer, indicator LED, power switch and stretch sensor attachment (RCA, female) to it from the back before screwing the box back together.
I'm powering the Arduino with a 9V battery. I've got 2 of them wired in parallel so i'll get the same voltage, but double the amperage (it'll last longer).
Program the Arduino with the provided code.
To monitor breathing, we will be making a chest strap that is outfitted with a stretch sensor. The expansion and contraction of the chest will provide us with data that we can use, in code, to extrapolate what normal breathing is, and therefore determine with a larger than usual inhalation (followed by large exhalation) is. A 10 or 20K potentiometer will be used to dial in a threshold value, which will represent how large of an inhalation is associated with a sigh.
I purchased my stretch sensor from Merlin Robotics, a company in the UK. They stock a variety of sizes. I'm using the 20cm sensor.
In my circuit, i'm amplifying the signal from the sensor with a resistor bridge and an OpAmp chip (see diagram). This is the method suggested by the manufacturer. You can find the datasheet on the internet. Note: I imagine a similar idea could be done with pressure sensor instead of a stretch sensor. You'd could attach the pressure point on the sensor to some kind of tubing and wrap that tubing around the chest.
Drill holes in the front face of the carrying case and attach the potentiometer, indicator LED, power switch and stretch sensor attachment (RCA, female) to it from the back before screwing the box back together.
I'm powering the Arduino with a 9V battery. I've got 2 of them wired in parallel so i'll get the same voltage, but double the amperage (it'll last longer).
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amperage and current mean the same thing. when you put the two batteries in parallel you get a higher amperage/current at the same *voltage* than that of a single battery.
consequently, you get a higher voltage and the same current when putting the batteries in series.
batteries in series will
- will deliver the current that one battery can nominally deliver and
- the overall voltage will be the voltages of all batteries added up.
batteries in parallel will as a unit
- have the nominal battery voltage of a single battery and
- deliver a current which is the sum of all battery currents.
these are generalisations, take them with a grain of salt please. and never ever make a mashup of non-identical batteries, unless you know what you are doing and not only think that you know what you are doing....