I have a project which will have a device reading the Arduino analog outputs. The other device is 0-5V 10 bit. From what I can gather the Arduino can do 8 bit analog out via PWM pins. What exactly does this mean? Every time I try and find info all I get is pages and pages of DAC datasheets. will the readings be off, will it just not work, or something else?
I'm guessing that you are thinking (hoping?) the "analog out" is a voltage say from 0 to 5 volts. Not so. It's a periodic waveform with a variable duty cycle - PWM.
Yeah, well that was my next hurdle, I was kind of assuming the Arduinos analog out via PWM was a sort of psuedo analog that would not work with the Netiom. So given that this is all now hypothetical what would the answer to the question be? Would an 8 bit analog out be read by a 10 bit analog in in any fashion?
The Arduino doesn't provide true analog outputs, but it can produce pulse-width-modulated digital outputs. These are suitable (with amplification where necessary) for driving LEDs, motors and some other devices. If you need a true analog output, the best solution is to connect an external DAC chip. However, if you only need to vary the analog signal slowly, and the input to the other device is high impedance, then you may get away with using an RC network to smooth the PWM output. You can combine two PWM outputs to increase the resolution above 8 bits.
You say that the other device is 0-5v 10 bit. Does it have a digital input as well as an analog input?
dc42:
You say that the other device is 0-5v 10 bit. Does it have a digital input as well as an analog input?
Yes, but nothing programmable. The aim is for the Arduino to output the current temperature of several zones via analog for the Netiom to read via its analog inputs. The Arduino is controlling the heating and the Netiom is a sort of building status monitor displaying current temps, alarm and lighting status from several sources on a web page.
Regarding the 8 bit into 10 bit, from what I have been reading I think I have confirmed what I thought would happen, the 10 bit input would read the 8 bit output fine but there would be a section of the range unused which I could ignore in programming on the other end.
the Arduino can do 8 bit analog out via PWM pins. What exactly does this mean?
Grumpy_Mike:
the Arduino can do 8 bit analog out via PWM pins. What exactly does this mean?
Extremely useful site, as always. Need to experiment with this a bit and see what works, high accuracy isn't critical so filtering the PWM would be ideal as long as the other device is happy with that.
Need more breadboard!