Which Croduino to use with 8 DHT22 sensors and SPI D/A converters

Soldered_Bot · June 28, 2017, 1:53pm

Customer:

Which Croduino type would you recommend for use with 8 DHT22 sensors? The same Croduino would need to communicate with 12-bit SPI D/A converters (for 16 channels, probably 2 x 8). I also need more details (especially the dimensions of the part that goes into soil) for a CO2 sensor like the one shown. I haven’t found a similar sensor in your product range - can you source something like it?

Original message (Croatian)

Molim vas za info koji bi vi CRODUINO tip preporučili za korištenje u kombinaciji s 8 DHT22 senzora:

Isti taj CRODUINO bi trebao moći komunicirati s 12-bitnim SPI D/A konverterima (za 16 kanala = vjerojatno 2 X 8).

Također bih vas molio više detalja (naročito dimenzije dijela koji ide u tlo) za sljedeći sensor:

CO2 senzor kao recimo ovaj na donjoj slici nisam našao u vašem prodajnom program, da li nešto slično možete nabaviti?

Puno vam hvala na pomoći. LP,

[name removed]

mr.sc. [name removed], dipl.ing.el.

Stručni suradnik specijalist | Associate Specialist

Hrvatski operator tržišta energije d.o.o. | Croatian Energy Market Operator Ltd.

POSLOVNA JEDINICA OBNOVLJIVI IZVORI ENERGIJE I VISOKOUČINKOVITE KOGENERACIJE | RENEWABLE ENERGY SOURCES AND HIGH EFFICIENCY COMBINED HEAT AND POWER DIVISION

Odjel obračuna i planiranja sustava poticaja i premija | Planning and Accounting of Subsides and Premium System Department

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Izjava o odricanju od odgovornosti (http://www.hrote.hr/default.aspx?id=204) / Disclaimer (HROTE - Hrvatski operator tržišta energije d.o.o.)

Razmislite prije ispisa ove poruke! / Think before printing this e-mail!

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Originally submitted via email support on 28 June 2017. Migrated to the forum for community visibility.

Soldered_Bot · June 28, 2017, 4:22pm

Soldered Support:

The best criterion for choosing a microcontroller depends on what you’ll do with the collected data. Generally, I’d recommend the Basic2 board, which is excellent for prototyping and has a sufficient number of I/O pins and SPI communication: Soldered: Open-Source Electronics, Boards, Sensors & Modules – Soldered Electronics ; Soldered: Open-Source Electronics, Boards, Sensors & Modules – Soldered Electronics

DHT22 uses one-wire digital communication, but you can also use analog pins.

From soil moisture sensors, expect only an approximate state. The sensor outputs an analog signal, but even if you calibrate it very precisely to get the actual percentage of soil moisture, the chemical composition of the soil entering the ground would change and so would the measurement results. If you want to divide soil moisture into 3 or 5 ranges, it’s quite sufficient.

The MQ135 sensor is very sensitive to CO2, but keep in mind it will also respond to carbon monoxide: Soldered: Open-Source Electronics, Boards, Sensors & Modules – Soldered Electronics

If you want to get the number of particles in the air (ppm), do not use MQ135. A better solution is the MG811 you sent. However, you will also need to calibrate it according to temperature, humidity, and the proportion of other gases. I think the best third option is the K-30 sensor. We can source them.

Industrial solution: https://ctiengineering.com/products/34-GasGuard-CO2/?_vsrefdom=adwords&gclid=CISzt-_Ux9ECFUm2wAodi7UItw

Measuring CO2 in the air is very difficult, both indoors and outdoors - I’m not sure how it’s done in open spaces. Generally it’s measured together with carbon monoxide, and based on that the air quality is determined, which the MQ135 will do well.

MQ135 and MG811 need to be heated before measurement, which consumes quite a bit of current, so they’re not recommended if the power source is a battery.

Original message (Croatian)

zahvaljujemo na upitu.

Ovisno što biste radili s prikupljenim podacima bi bio najbolji kriterij za odabir mikrokontrolera. Generalno, preporučio bih Basic2 pločicu koja je odlična za prototipiranje i ima dovoljan broj I/O pinova, kao i SPI komunikaciju : Soldered: Open-Source Electronics, Boards, Sensors & Modules – Soldered Electronics ; Soldered: Open-Source Electronics, Boards, Sensors & Modules – Soldered Electronics

DHT22 je one-wire digitalna komunikacija, ali možete koristiti i analogne pinove.

Od senzora koji mjeri vlagu u tlu očekujte samo okvirno stanje. Senzor dalje analogni izlaz, ali čak i kada biste ga vrlo detaljno kalibrirali da dobijete stvarni postotak vlage u tlu kemijski sastav probe koja ulazi u tlo bi se mijenjala te s njoj i rezultati mjerenja. Ako mislite podjeliti vlagu u tlu na 3 ili 5 raspona on je sasvim dovoljan.
MQ135 senzor je vrlo osjetljiv na CO2, ali imajte na umu da će aktivirati i ugljik-monoksid: Soldered: Open-Source Electronics, Boards, Sensors & Modules – Soldered Electronics

Ako želite dobiti broj čestica u zraku (ppm) nemojte koristiti MQ135, bolje rješenje je MG811 koji ste poslali. Međutim i njega ćete morati kalibrirati prema temperaturi vlagi i udjelu ostalih plinova. Smatram kako je najbolje treće rješenje K-30 senzor. Možemo ih pribaviti.
Industrijsko rješenje: https://ctiengineering.com/products/34-GasGuard-CO2/?_vsrefdom=adwords&gclid=CISzt-_Ux9ECFUm2wAodi7UItw
Udio CO2 u zraku je vrlo teško mjeriti i u zatvorenim prostorima, nisam siguran kako to rade na otvorenim prostorima. Uglavnom se mjeri zajedno s ugljik-monoksidom i prema tome određuje kvaliteta zraka što će MQ135 dobro napraviti.
MQ135 i MG811 je potrebno zagrijati prije mjerenja pri čemu troše poprilično struje pa nisu preporučljivi ako je izvor napajanja baterija.

Soldered_Bot · July 3, 2017, 2:24pm

Customer:

I have a few more questions:

In examples, serial communication is usually found as: “Serial.begin(9600);” - this is quite slow (compared to today’s average data transfer speed). Is it possible to use a higher speed, and if so, what is the recommended maximum?
What is the maximum allowed distance of a sensor, e.g. DHT11, from Croduino for the device to work correctly?
Does Croduino have commands like “timer/counter” and the ability for interrupts?
What do you recommend for communication between Croduino NOVA and, say, Croduino Basic 2 (I would like to send/receive data from Croduino Basic 2 to/from the Internet)? Also, do you have an example of directly writing to a database (e.g. MySQL) data from Croduino Basic 2 (via Croduino NOVA)?

Original message (Croatian)

Ako nije problem postavio bih još nekoliko pitanja:

U primjerima se najčešće za serijsku komunikaciju nailazi: „Serial.begin(9600);“ → to je poprilično „sporo“ (u odnosu na današnju prosječnu brzinu prijenosa podataka); da li je moguće koristiti veću brzinu te ako je, kolika je preporučena maksimalna?
Kolika je max. dozvoljena udaljenost senzora npr. DHT11 od Croduina da bi uređaj radio korektno?
Da li Croduino ima naredbe kao: „timer/counter“ te mogućnost interupta?
Što preporučate za način komuniciranja između Croduino NOVA i recimo Croduino Basic 2 (htio bih podatke s Croduino Basic 2 slati/primati na/s Interneta)? Također da li imate primjer direktnog pisanja u bazu (recimo MySQL) podatke s Croduino Basic 2 (preko Croduino NOVA)?

Hvala vam puno na pomoći. LP,

[name removed]

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Soldered_Bot · July 3, 2017, 5:32pm

Soldered Support:

Yes, 9600 is quite slow. If you open the Serial monitor in Arduino, you’ll see baud options in the bottom right. For the bridge on Croduino Basic2/NOVA (CP2102) you can go with 230400. I personally always use 115200 and haven’t had the need for higher speeds.

The most important is the wire for communication, which noise can affect because it’s digital communication. Because of that, it depends quite a bit on the conditions in which the sensor will be located. My estimate is 5m safely, 10m probably. Best to test and see if results are consistent.

Of course! All timers and interrupts are the same as on Arduino.

You can get the time since startup with the millis() command in milliseconds or micros() in microseconds.

If you need an event every few times: Arduino Playground - HomePage (you can insert sleep in the meantime)

For interrupts: Arduino Playground - HomePage

Serial or I2C communication for connecting these two boards - whichever is more familiar to you. I would personally choose I2C: I2C Between Arduinos : 5 Steps (with Pictures) - Instructables

For sending data to a MySQL database, we’ve even written about it before, but I can’t find it now. Basically you need a small PHP script between the board and the database that receives data via GET and inserts it into the database. Example script: NodeMCU-MySQL/PHP/index.php at master · mwhprojects/NodeMCU-MySQL · GitHub

How you’ll do the connection between Basic2 and NOVA isn’t part of a tutorial, but it’s the I2C mentioned above.

Let me know if anything remains unclear.

Original message (Croatian)

naravno, zato smo tu!

Je, 9600 je prilično sporo. Ako otvorite Serial monitor u Arduinu, dolje desno ćete vidjeti opcije baud-a. Za bridge koji se nalazi na Croduino Basic2/NOVA(CP2102) možete ići s 230400. Ja osobno koristim uvijek 115200 i nisam imao potrebe za većim brzinama.
Najvažnija je žica za komunikaciju, kojoj noise može smetati jer se radi o digitalnoj komunikaciji. Zbog toga, dosta ovisi i o uvjetima u kojima će se senzor nalaziti.. Moja procjena je 5m sigurno, 10m vjerojatno. Najbolja je testirati i vidjeti jesu li rezultati konzistentni.
Naravno! Sve timeri i interrupti su isti kao i na Arduinu.
vrijeme od pokretanja možete dobiti naredbom millis() u milisekundama ili micros() u mikrosekundama
ako trebate događaj svakih nekoliko vremena: Arduino Playground - HomePage (u međuvremenu možete ubaciti sleep)
za interrupte: Arduino Playground - HomePage
Serijska ili I2C komunikacija za povezivanje ove dvije pločice - što Vam je već poznatije.. Ja bih osobno odabrao I2C: I2C Between Arduinos : 5 Steps (with Pictures) - Instructables

Za slanje podataka u MySQL bazu, pisali smo čak i o tome nekada prije, ali sada ne pronađem.. uglavnom trebate malu php skriptu između pločice i baze koja je preko GET-a dobivati podatke i ubacivati ih u bazu. Primjer skripte: NodeMCU-MySQL/PHP/index.php at master · mwhprojects/NodeMCU-MySQL · GitHub

— kako ćete odraditi povezivanje basic2 i NOVA nije dio tutorijala, ali to je ovaj gore već spomenuti I2C

Javite ako je nešto ostalo nejasno.

Soldered_Bot · July 5, 2017, 1:36pm

Customer:

I have a few more questions:

Can I2C and serial communication, and SPI and serial communication, be used simultaneously on Croduino Basic 2?
Are your power supplies (AC/DC mini power supply, step-up module 150 W) designed with “isolated ground” - that is, can they be connected to provide negative output voltage?
If we ignore connection methods with Croduino Basic 2, which option would you recommend for use: a module with an Ethernet shield or Croduino NOVA, if the criteria are data transfer speed and reliability?
Does your RS-485 have galvanic isolation?

Original message (Croatian)

Ako može molim vas imam još par pitanja:

Da li se može na Croduino Basic 2 istovremeno koristiti I2C i serijska komunikacija te SPI i serijska komunikacija?
Da li su vaša napajanja (AC/DC mini napajanje, step-up modul 150 W) izvedena s „izoliranom nulom“ – odnosno da li se mogu spajati da daju negativni izlazni napon?
Ako se zanemare načini spajanja sa Croduino Basic 2, koju opciju bi preporučili za koristiti: modul s Ethernet shieldom ili Croduino NOVA, ako je kriterij brzina prijenosa podataka i pouzdanost?
Da li vaš RS-485 ima galvansko odvajanje?

Toliko za sada, puno vam hvala unaprijed.

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Soldered_Bot · July 9, 2017, 3:33pm

Soldered Support:

Of course, just ask!

Yes, of course! It certainly won’t be literally simultaneous (since it’s a classic 8-bit microcontroller), but it will be fast enough that you won’t notice.

Unfortunately I can’t know because those two modules are finished modules we buy in that form - they’re not our products. Best to test, but I’m fairly confident at first that the step-up 150W is not isolated, but the mini power supply could be.

Wired connection is always more reliable than wireless (general rule because wireless protocols have much less checking for correct data transmission). As for speed, I believe you won’t notice the difference because both will be able to transmit data at speeds faster than the microprocessor can process. If there are differences, it will be less than 10ms. Maybe this matters to you: NOVA runs at 48MHz, while the Ethernet shield you connect to the microcontroller is 8MHz.

That module does not have galvanic isolation.

Original message (Croatian)

naravno, samo pitajte!

Da, naravno! Sigurno da to doslovno neće biti istovremeno(budući da se radi o klasičnom 8bitnom mikrokontroleru), ali će biti dovoljno brzo da čovjek ni ne može primjetiti.
Nažalost ne mogu znati jer su ta dva modula gotovi moduli koje kupujemo u tom obliku - nisu naši proizvodi. Najbolje je isprobati, ali prilično sam siguran na prvu da step-up 150W nije izoliran, ali mini napajanje bi moglo biti..
Žična konekcija je uvijek pouzdanija od bežične(generalno pravilo jer protokli imaju puno manje provjera ispravnog prijenosa podataka). Što se tiče brzine, vjerujem da razliku nećete primjetiti jer će oba biti u mogućnosti prenositi podatke brzinama većim nego što ih mikroprocesor može obraditi. Ako i razlike budu postojale, radit će se o manje od 10ms. Možda Vam nešto znači, NOVA radi na 48MHz, dok Ethernet shield spajate na mikrokontroler od 8MHz.
Taj modul nema galvansko odvajanje.

Soldered_Bot · July 21, 2017, 6:49am

Customer:

I need pinouts and connection diagrams for the following components/modules: RS485 module, AC/DC power supply 5 VDC, Arduino Ethernet shield (especially the pins marked ICSP), and Li-ion battery charger with protection.

Original message (Croatian)

Hvala vam na prijedlogu – poslati ću vam modul sljedeći tjedan. Ne morate mi odmah slati drugi modul i Croduino Basic 2 (odlučio sam ga naručiti), nego možete sve poslati kada dobijete napajanje i ventil za vodu).

Da li mi u međuvremenu pomoći gdje da nađem sheme spajanja ili „pinout“ za sljedeće komponente/module koje sam naručio:

RS485 modul,

AC/DC napajanje 5 VDC,

Arduino Ethernet shield (naročito pinove označene s ICSP),

Punjač za Li-ion bateriju sa zaštitom.

Hvala vam unaprijed.

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Soldered_Bot · July 27, 2017, 9:53am

Soldered Support:

Datasheets and other links can be found on the product page to the right of the image. These are direct links for the modules you’re interested in:

RS485:

https://arduino-info.wikispaces.com/SoftwareSerialRS485Example

AC/DC:
On the edges of one side are THT pins for input (AC) marked J1, and on the other side for output (DC) marked +5V and (-).

Ethernet shield:
See the connector diagram: https://www.allaboutcircuits.com/uploads/articles/Pinkle_microcontroller_design_1.jpg

Pinout for connecting to Basic2: Soldered: Open-Source Electronics, Boards, Sensors & Modules – Soldered Electronics

Battery charger:
5V connect to pins IN+ and IN- or USB connector, battery to B+ and B-. We recommend connecting via an adapter (e.g. phone charger) because the computer can provide only 500mA which will charge the battery very slowly.

When connecting, pay attention to polarities.

Original message (Croatian)

upravo smo primili Vaš paketić, šaljemo sve skupa kako ste predložili.
Datasheet i ostale linkove možete pronaći na stranici proizvoda desno od slike. Ovo su direktni linkove za module koji Vas zanimaju:

RS485:
Soldered: Open-Source Electronics, Boards, Sensors & Modules – Soldered Electronics
https://arduino-info.wikispaces.com/SoftwareSerialRS485Example

AD/DC:

na rubovima se jedne strane nalaze se THT pinovi za ulaz (AC) oznaka J1, a s druge za izlaz (DC) oznaka +5V i (-).
Ethernet shield

pogledajte shemu konektora: https://www.allaboutcircuits.com/uploads/articles/Pinkle_microcontroller_design_1.jpg

pinout prema kojem ga spajate na basic: Soldered: Open-Source Electronics, Boards, Sensors & Modules – Soldered Electronics
Punjač za bateriju:

5V spajate na pinove IN+ i IN- ili USB konektor, bateriju na B+ i B-. Preporučujemo spajanje preko adaptera (npr. punjač od mobitela) jer računalo može dati samo 500mA što će puniti bateriju vrlo sporo.
Prilikom spajanja pripazite na polaritete.