float is enough for temp & humidity readings. Using double would give no advantage because 1) no sensor used with arduino can measure temperature or humidity more accurately than float can represent and 2) because in Uno, double and float are the same (they are different on some more advanced, 32-bit Arduino boards)
thanks paul,
ok in this case ..but i dont know now, what sort of values does 74hc4067 reads in
and then give to arduino naturally..
datasheets dont day anything about real application
conditions in cooperating with controllers and so far..
i'll see if its here..
74hc4067 is an analog multiplexer/demultiplexer chip. It will accept any input voltage between ground and Vcc and pass that to the output, in either direction. You can think of it like a 16-position mechanical switch.
Naturally, it's not perfect. It will introduce some extra noise into the analog signal, and may also reduce the signal voltage a little, especially if more current is drawn from the output by the circuit it is connected to. The Arduino's input pins are pretty high impedance, so they won't draw much current at all.
@rezox plans to use the 74hc4067 to connect multiple dht22 temp/humidity sensors. These have digital outputs, so don't strictly need an analog multiplexer at all. A digital multiplexer like 74hc138 would work equally well. But an analog multiplexer should also work well. The additional noise and signal level reduction should not affect the digital signals output by dht22 or other digital sensors.
ok, thats like earlier AD-converters in DIL-Format, i guess..
oh, thats very interesting for me..some of my projects only need digital values..
in the cases if have worked until now i used analog-pins for output to leds
with 0=LOW and 255=HIGH
so will order that 74hc138 additionally, if can get it on a cheap way..
isnt that the opposite funtion ? called DE-Multiplexer or similar ?
i need more input-pins for reading touch-sensors or light-barriers or
readcontacts on model-railway-issues with 5V commonly used
for output i use an pwm-expander what also works mixed with leds
so that case is solved so far
You are correct, 74hc138 is a demultiplexer only.
74hc151 is a multiplexer.
An advantage of 74hc4067 is that it can be either. Plus it has 16 inputs/outputs.
For your projects you can also consider i2c I/o expanders like pcf8574, pcf8575, mcp23008, mcp23017, sx1509....
But this topic belongs to @rezox. You should start your own topic to discuss these things, unless you are convinced that the advice will be useful for @rezox also.
hi ,
with mcp23017 i had no luck..concurrence with lcd-display hd44780
could not be solved though i tried to modify i2c-adress of mcp..and at least
it was destroyed by a small accident in my room..
i'll give a try to 74hc4067 - it is ordered already - the others you have listed are I2C
i dont like now...
thanks for your tipps anyways !
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