Use analog pins for power/ground?
#1
Posted 09 October 2011 - 11:20 PM
Somebody has probably already asked this, but the keywords are so general ("analog", "pin", "power", "ground") that I haven't been able to find it.
The BlinkM documentation suggests that it can be plugged directly into a 'duino. If so, I guess it would be using A2 and A3 as GND and 3.3V. I think I read elsewhere that the Netduino analog pins come up at 3.3V when it is powered on... Is it safe to have 3.3V to the device's VCC and GND? Would it just mean that the device has no voltage potential to operate, but that it wouldn't smoke and that it would begin operating once the A pin connected to GND is set to 0V?
I'd like to make a little standoff that holds sensors off to the side, away from the minor heat island caused by the Netduino. I want to use a strip/vero board with 8 lines, 6 of which will be connected to A0 through A5. Then, with two jumper wires and three cuts, I can connect the two i2c sensors and one analog sensor, but I'd need to use A2 as a 3.3V supply and A1 as ground. If you've ever seen pirates make somebody "walk the plank", that's what I'm doing with the sensors. Ship = Netduino, plank = strip board, pirates = me.
I've thought about alternatives (e.g. sensors dangling from ribbon connectors) but I really have my heart set on having them walk the plank, if I can, and it all hinges on using A2 as 3.3V device supply and A1 as GND for devices. Any reason not to try this?
#2
Posted 10 October 2011 - 12:52 AM
Hi,
Somebody has probably already asked this, but the keywords are so general ("analog", "pin", "power", "ground") that I haven't been able to find it.
The BlinkM documentation suggests that it can be plugged directly into a 'duino. If so, I guess it would be using A2 and A3 as GND and 3.3V. I think I read elsewhere that the Netduino analog pins come up at 3.3V when it is powered on... Is it safe to have 3.3V to the device's VCC and GND? Would it just mean that the device has no voltage potential to operate, but that it wouldn't smoke and that it would begin operating once the A pin connected to GND is set to 0V?
I'd like to make a little standoff that holds sensors off to the side, away from the minor heat island caused by the Netduino. I want to use a strip/vero board with 8 lines, 6 of which will be connected to A0 through A5. Then, with two jumper wires and three cuts, I can connect the two i2c sensors and one analog sensor, but I'd need to use A2 as a 3.3V supply and A1 as ground. If you've ever seen pirates make somebody "walk the plank", that's what I'm doing with the sensors. Ship = Netduino, plank = strip board, pirates = me.
I've thought about alternatives (e.g. sensors dangling from ribbon connectors) but I really have my heart set on having them walk the plank, if I can, and it all hinges on using A2 as 3.3V device supply and A1 as GND for devices. Any reason not to try this?
The device won't smoke, but the netduino will. See http://www.netduino....duino/specs.htm - you're only allowed to draw 2mA per analog pin, your LED will draw more. You'll need to use the "real" 3.3V and ground pins of the netduino.
-- H.L. Mencken, "What I Believe"
#3
Posted 10 October 2011 - 01:30 AM
#4
Posted 10 October 2011 - 02:36 AM
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