Timeline for compensating for voltage divider computing sensor board analog reading
Current License: CC BY-SA 4.0
8 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Dec 11, 2021 at 15:01 | comment | added | D.A.S. | I measured mass and counts by using air deflection for a calibrated nozzle air flow by deflecting particles with a transverse pitot tube with IR reflection and counts of particles per second then extrapolated to particles per cubic foot. | |
| Dec 11, 2021 at 14:57 | comment | added | D.A.S. | I have experience using a 16 channel Laser particle counter and the particle count increases inversely to the particle size over a several decades in random dust. However smoke particles cover a small range of large particles. I used this to measure office and manufacturing environments for HDD ranging up to 1M particles per cu.ft down to 100kp/cf. HEPA flow booths are 10kp/cf max, clean room rooms & HDD enclosures with recirculating HEPA filters are 1 to 10 p/cf all for >0.1um yet far more particles exist under this size . This range indicates 6 orders of magnitude. | |
| Dec 11, 2021 at 5:25 | comment | added | Richard Chambers | @TonyStewartEE75 what do you mean by "Dust tends to have a log scale"? Do you have an article that would explain dust measurement? I think the underlying reason for the voltage divider is to drop the AOUT voltage to within the range of an A/D converter on an MCU. The Arduino code sets the range for the A/D on the board to be 0.0 v to 1.1 v. I'm not sure about other MCU devices such as STM32 however I suspect the value was chosen to have a range compatible with most A/D converters on common MCUs. | |
| Dec 11, 2021 at 5:16 | history | edited | Richard Chambers | CC BY-SA 4.0 |
added image with schematic.
|
| Dec 11, 2021 at 4:51 | history | edited | Richard Chambers |
added microcontroller tag as this is not Arduino specific.
|
|
| Dec 10, 2021 at 20:57 | comment | added | D.A.S. | I can see possible over-voltage issues of using a 5V boost supplied signal if Arduino shares the same V+ input. A series current limiting R should have been adequate for the signal. No good reason for 1/11. Averaging random noise improves st .dev by sqrt(n) so not much improvement. Dust tends to have a log scale, so a linear scale with a high threshold is pretty coarse. | |
| Dec 10, 2021 at 20:00 | answer | added | user4574 | timeline score: 1 | |
| Dec 10, 2021 at 19:10 | history | asked | Richard Chambers | CC BY-SA 4.0 |