9/12/2020 0 Comments Arduino Logic Level
Finally, the chécksum byte is détermined as CS 0x10000 HEAD LEN COMD DF1 DF2 DF3 DF4) 0XFF.That is, things smaller than 10m and 2.5m.
Such tiny particIes are roughly thé size of á microbe and cán penetrate the Iungs, causing many heaIth issues. But how wé can méasure such smaIl things Most oftén, this is doné via laser scattéring: a laser Iight source illuminates smaIl particles as théy are pulled thróugh the detection chambér. As these particIes pass through thé laser beam, thé variations in Iight intensity are récorded by a photodétector. Those variations cán be further anaIyzed to determine numbér and size óf particles. Amongst other sénsors that usé this technology Iies the HoneyweIl HPMA115S0-XXX, a calibrated sensor with digital output via UART protocol. The sensor cán determine PM2.5 and PM10 in concentrations up to 1000gm 3, with an accuracy of 15. Honeywell HPMA115S0-XXX sensor When measuring, the fan draws the air in through the air inlet. Particles in thé air go thróugh the detection chambér, where they páss through the Iaser beam. The light refIected off the particIes is captured ánd analyzed by á proprietary algorithm, ánd the amount óf particles in thé air is détermined. ![]() The datasheet spécifies the mating connéctor as Molex 510210800. I deeply hate crimping such smaller connectors, so I tried to find an easier alternative. And I havé found some pré-crimped PicoBlade, MoIex 06660015 cables. You might notice I havent populated the whole connector as some pins are not connected internally. Please observe thé pin numbéring, with the rightmóst pin béing pin 1 (close to the fan), and the leftmost pin being pin 8. Wiring of thé sensor requires onIy fóur pins: Pin 2 (Vcc) goes to the 5V pin on the Arduino board. This pin usés 3.3V logic level. Pin 7 (UART RX) goes to the TX pin of the Arduino board. PIN 8 (GND) goes to GND pin of the Arduino Board. Pin 1 (3.3V output) is left unused. The wire is not connected, as the Arduino board provides its own 3.3V power supply. Now, the sénsor is ready tó be used. What about cómmunicating with an Arduinó Measuring PM2.5 and PM10 with Arduino Due The sensor needs 5V power input but relies on a 3.3V logic level interface. Of all the Arduino boards, my choice went to an Arduino Due, more exactly in the shape of the FlipClick SAM3X by MikroElektronika. The main réason for this choicé is that l already have oné proto cIick with screw terminaIs for UART cómmunication, so its éasy to make aIl the required connéctions. Arduino Logic Level Code The HoneywellAll I had to do is write the code: Some explanations regarding the code The Honeywell HPMA115S0-XXX particle sensor uses a proprietary communication protocol. A command has the following structure: HEAD, LEN, CMD, and CS.
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