(r3) BShinyeiNopPPD42NS < IoT_Course

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---+ The Shinyei !PPD42NS sensor

This sensor emits a low occupancy time signal where the relative time the signal is in low state is measured.

The connections as are follows:
| Shinyei pin | !WeMos Pin | GPIO | Comments |
| 1: Common (GND) | GND | | |
| 2: OUTPUT(P2) | D6 | 19 | through voltage divider 5V - 3.3V |
| 3: INPUT(5V DC 90mA) | 5V | | |
| 4: OUTPUT (P1) | D7 | 23 | through voltage divider 5V - 3.3V |
| 5: INPUT T1 | D0 | 26 | DAC |
---++ Reading the signal

To get a feeling about the signals emitted by the Shinyei !PPD42NS we first write a very simple program (pulses.py) that reads the P1 data line every 1 ms and saves the result in an array. It does so during 10 s. After data taking, the results are printed on the serial line.

We can run the program with
<verbatim>ampy run pulses.py > data.txt</verbatim>

and thus redirect the results into a file that can be plotted with gnuplot.

<img alt="smoke.png" height="598" src="%ATTACHURL%/smoke.png" title="smoke.png" width="662" />

The plot shows a measurement where a match has been lighted and the smoke blown into the sensor. The particle concentration can be measured by calculating the relative time the signal is low with respect to the measurement period (low occupancy time).

-- %USERSIG{UliRaich - 2022-06-01}%

---++ Comments

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I	Attachment	History	Action	Size	Date	Who	Comment
png	smoke.png	r1	manage	26.4 K	2022-06-03 - 19:17	UliRaich

Topic revision: r3 - 2022-06-04 - UliRaich