Hello.
Is it possible to use analog temperature sensors (TMP35) with my i2c i/o expander (MCP23017)?
From what I can see so far, it's only good for connecting buttons as it can only handle high/low and not analog signals. Is this true?
Is there a way for me to connect my sensors through one bus?
Hm, usually people respond really fast here.
If it's confusing and something needs clarification - please ask. I'm not a native speaker.
Is it possible to use analog temperature sensors (TMP35) with my i2c i/o expander (MCP23017)?
No.
From what I can see so far, it's only good for connecting buttons as it can only handle high/low and not analog signals. Is this true?
Yes.
Is there a way for me to connect my sensors through one bus?
No.
Thanks. Is it possible to increase the amount of analog inputs on the Uno?
Yes, put a multiplexer in front of the analogue inputs.
See this for an example:-
http://www.thebox.myzen.co.uk/Hardware/MIDI_Footsteps.html
What about something like this, though?
It claims to expand analog inputs via i2c.
http://blueberryde.com/shop/24-channel-analog-expander-shield/
As far as multiplexers go, I'm thinking about this, is this an okay one?
http://www.ebay.com/itm/GeTech-CD74HC4067-Analog-Digital-MUX-Breakout-compatible-with-Arduino-iduino-/251409425103
Yes they would both do the job. The shield is only 8 bits where as the multiplexer will allow you to use the internal 10 bit converter.
But you said it's impossible to connect the sensors on one bus - and the shield apparently lets them connect via i2c. Is there an i2c analog expander I can buy separately? Or what do they use there?
But you said it's impossible to connect the sensors on one bus
No I didn't.
You asked:-
Is it possible to use analog temperature sensors (TMP35) with my i2c i/o expander (MCP23017)?
and I said:-
you could not use an analogue sensor with a MCP23017 because that is a digital chip.
Did you mean could you have a MCP23017 and an I2C temperature sensor on the same I2C bus, that is a totally different question and the answer is that yes you can.
I asked - Is there a way for me to connect my sensors through one bus?
You said- No.
Now that shield apparently lets me does that - extend analog inputs via an i2c bus.
I asked - Is there a way for me to connect my sensors through one bus?
That is not what your words conveyed to me.
Is it possible to use analog temperature sensors (TMP35) with my i2c i/o expander (MCP23017)?
"with" is the wrong word you should have said along side or on the same bus as.
You used, at best, sloppy ambiguous phrasing.
That is not what your words conveyed to me.
This is exactly what I asked though, it was a quote.
Anyway, now my question is, how can I put multiple analog inputs on an i2c bus, just like they do in the shield? What IC does that?
As long as those i2c sensors use different addresses, you just connect them to your arduino SDA and SCL lines (don't forget pull-ups resistors), supply power and GND and you are good to go.
i2c addresses could be found with a i2c scan code (search for it) or by reading corresponding manuals.
And I'm not sure why you were talking about MCP port expander - it's designed for different purposes.
I don't have i2c sensors. I need an i2c analog input expander, what IC does that?
Oh, look, you'll need to me more clear about that then.
If you need to somehow connect analog sensor to i2c, you'll need to first read that sensor and convert result into digital, and then send it via i2c. I can see 2 ways of doing that:
- Use an i2c ADC (analog to digital converter). Something like that: ADS1015 12-Bit ADC - 4 Channel with Programmable Gain Amplifier [STEMMA QT / Qwiic] : ID 1083 : $9.95 : Adafruit Industries, Unique & fun DIY electronics and kits. This particular module has 4 analog inputs.
- Use a smaller arduino (or ATMega chip with some extra hardware), program it as i2c slave and use its ADCs.
Option 1 would be easier, I guess.
P.S.: here is a 16-bit version: ADS1115 16-Bit ADC - 4 Channel with Programmable Gain Amplifier [STEMMA QT / Qwiic] : ID 1085 : $14.95 : Adafruit Industries, Unique & fun DIY electronics and kits
Glebun:
I don't have i2c sensors. I need an i2c analog input expander, what IC does that?
There are lots of A/D converters with I2C interfaces.
See some of the choice here:-
Thank you all!
Last question - what's the most popular and well-documented IC (maybe even with an own library?). I don't need a breakout board, just looking to get a cheap IC from ebay. Sorry if I'm asking too much questions or if I wasn't clear.
IC? For what purposes?
Glebun:
what's the most popular and well-documented IC (maybe even with an own library?).
This has:-
http://forum.arduino.cc/index.php?topic=23714.0;wap2