Hi:
I am trying to control lots of hall effect flowmeter and read the pulse input.
I know for output usage like LED, shift register could be used.
But how about input.
What mux DAQ chip I can use?
Thanks!
You control a flow meter by regulating the flow through it. Other than that, there is not much you can do.
A better description of what you really want to do might be helpful, starting with a definition of "lots of".
Lots of means multiple.
Or I think my question should be what is the normal mux daq chip for Arduino.
Thanks!
perphy:
Lots of means multiple.
Rather nebulous, and not necessarily correct either. It may actually mean "too many". This is perhaps better defined after counting the number of interrupt service pins on your Arduino. But perhaps not, as may be determined after you lift the secrecy veil from your intentions. You may even find that the above, and a proper definition of "lots", may determine your choice, and or even the need, of a MUX, not to mention whether a MUX will solve your problem.
perphy:
what is the normal mux daq chip for Arduino.
Based on Google hit counts, you answer appears to be the Texas Instruments ADS1115. You can put four in a single I2C bus and each has four channels.
ADS1115 Arduino: 169000
CD74HC4067 Arduino: 94300
MCP4728 Arduino: 40900
TCA9548A Arduino: 37500
74HC4067 Arduino: 15300
AS8510 Arduino: 4020
perphy:
Lots of means multiple.
Come on. Can't you count? I hope you can - so do count, and give us the number. That's how many "lots of" and "multiple" is for you.
With every pin on the Arduino having pin change interrupts available (except maybe A6 and A7), you can connect as many such pulse sensors as you have pins, and read them all. This provided the overall rate is not too high, some 10-50k total pulses a second will be a practical limit for a 16 MHz processor, depending on how efficiently you can code and what else the thing has to do.
Or I think my question should be what is the normal mux daq chip for Arduino.
What's a daq?
The ADS1115 is a 4-port ADC. Doesn't make sense to use an ADC to read a pulse output.
wvmarle:
What's a daq?
Much like 'mux' is an abbreviation for 'multiplexer' I believe that 'daq' is an abbreviation for 'data acquisition'. I just put "mux daq chip Arduino" into Google to get some device numbers and did a search for each device number and Arduino to see how associated they were.
Who knows, maybe the unspecified 'hall effect flow meter' has an analog output.
If the OP wanted useful answers they would say what the interface was for the "hall effect flow meter" they hoped to use. Interfacing 27 I2C flow meters will take much different hardware than interfacing three TTL Pulse flow meters.
You are looking for I/O expander chips with interrupt capability I believe. configure as inputs with
interrupt on change, process each pulse in an ISR.
Multiplexing and polling doesn't scale well, lots of flow sensors running at a high rate would need
a lot of polling and would be easy to miss one.
Using interrupts gives the best chance of handling this and makes the rest of the sketch simpler
I reckon.
The MCP23S17 has 16 I/O pins, an SPI interface (I2C may be too slow for this application), and can
generate interrupts on pin changes I believe.
I'm using lots of (3) Hall effect flow meters and use, as MarkT rightly pointed out, an (enable)interrupt service routine, ISR, to watch for the falling edge of the voltage signal (caused by the magnet whizzzing by). The sketch counts it and serial.prints to monitor at my desired sampling rate.