Pulse Necklace 01July2009: Difference between revisions
(New page: Choker Hack Notes, June 24th, 2009 We tried crimp beads with surface mount LED and conductive thread. Very difficult to make, and prone to break apart. Probably won't work for us. Othe...) |
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Choker Hack Notes, | ==Pulse Choker Hack Notes, July 1st, 2009== | ||
We | We disassembled the pulse watch, and found the sensor part consists of a little LED + photo diode part, with 4 wires. | ||
We tried to use the watch on our necks, and it did sometimes show a beat pattern, but it was irregular and the watch would not return a bpm reading. It didn't matter whether we had the clear "window" part or not. | |||
We measured the voltages. The LED has a voltage drop of .6V, and V+ of 2.8V. The photo diode had a reading of 1.2V without finger, 1.073V with finger. Whatever the pulse signal is with finger, it's too small for the multimeter to read. Clearly we'll have to build an amplifier circuit. | |||
Try using the conductive epoxy to attach conductive thread to a SM LED. It look a few attempts, but we did find a way to attach it that wasn't too much trouble. The epoxy takes a lot longer than 5 minutes to dry though - probably more like several hours. Method we used: "wet" the ends of the thread, and press them against the pads of the LED. Generalization: wet a whole bunch of thread ends in an array, press the LEDs down against them. Do it on wax paper or similar that the epoxy doesn't stick too. | |||
Latest revision as of 20:27, 7 July 2009
Pulse Choker Hack Notes, July 1st, 2009[edit | edit source]
We disassembled the pulse watch, and found the sensor part consists of a little LED + photo diode part, with 4 wires.
We tried to use the watch on our necks, and it did sometimes show a beat pattern, but it was irregular and the watch would not return a bpm reading. It didn't matter whether we had the clear "window" part or not.
We measured the voltages. The LED has a voltage drop of .6V, and V+ of 2.8V. The photo diode had a reading of 1.2V without finger, 1.073V with finger. Whatever the pulse signal is with finger, it's too small for the multimeter to read. Clearly we'll have to build an amplifier circuit.
Try using the conductive epoxy to attach conductive thread to a SM LED. It look a few attempts, but we did find a way to attach it that wasn't too much trouble. The epoxy takes a lot longer than 5 minutes to dry though - probably more like several hours. Method we used: "wet" the ends of the thread, and press them against the pads of the LED. Generalization: wet a whole bunch of thread ends in an array, press the LEDs down against them. Do it on wax paper or similar that the epoxy doesn't stick too.