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Pulse Sensor III: Heart Rate Variability
Ways to limit the sources of noise Where does the noise come from in the Modern Device Pulse / PSO2 sensor? I’ll make a list of some of the places I think noise comes from. Some of these will be supported by experiments to get rid of the noise and others will remain more speculative. […]
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Pulse Sensor II: Getting the Lights On
Analog vs Digital Sensors When it comes to sensors I was always an analog guy. Analog sensors put out voltages or currents that are easy to verify with a multimeter. Or if you really need a pretty picture then you can hook up an oscilloscope and see a very complete story. Analog sensors tend to […]
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Pulse Sensor I
Making a Pulse (SPO2) Sensor Many electronic hobbyists and people who are interested in science are aware that the human pulse may be detected by shining a light through a finger or earlobe. The technique is formally called photoplethysmography generally, but also more simply pulse oximetery and PSO2 sensing. It is the basis for the […]
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Full Spectrum Engineering 40W Hobby Laser
At Modern Device, we construct a lot of surface-mount printed circuit boards. The process involves putting paste solder on PCBs, and for that, you need stencils. We were using the Epilog Mini 24″ laser at (Providence’s) AS220 Fab Lab, but it wasn’t convenient to go to the lab every time we needed a stencil, and […]
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June Sale
It’s summer! Modern Device is having a sale in tandem with our European collaborators JeeLabs for the whole month of June. During the month of June, everyone who has previously purchased something from the Modern Device shop (i.e. before June 1st 2012) can use discount code “MD2012” to get 12% off all items. The sale […]