Thanks, I didn't think that a resistor was needed since it was on an output, but I am unable to make a very simple program run correctly so I became concerned that the lack of resistors had fried something.
Nevertheless you should ALSO read the link Harley pointed to
To my memory Parallax claims their Propeller outputs to be (nearly) shortcut safe, restricting the current to 30 - 40 mA. So it should be difficult to harm them. Another matter however is high current (> 1mA) input....
@rjo: You most likely connected +6 V from the batteries to an input pin. This is an absolute safe methode to kill it Note that modern accumulators deliver upto 5 A or even more
We get two conflicting answers here wrt to connection of a servo signal line to a prop output. Can we get some consensus on this?
Do you need a resistor between a prop output pin and a servo signal line? If so, what value? Will a resistor in series not cause the 3.3V to be too low for the servo to "react" to a pulse if the prop fires it?
I read the HOWTO... thread but there is a serious amount of over-info in there that isn't really readable for people without a degree in electronic engineering such as myself.
A smaller HOWTO without a zillion posts in it would be a very welcome gift for those with merely an interest to tinker a little with the propeller without getting into the electronics side as deeply as some of you more professional lot [noparse]:)[/noparse] A couple of example circuits of how to hook up a few devices with different functions, such a servo, a ping sensor, that kind of thing. I know the prop is for more advanced users and I have no problems Reading The Fine Materials or searching the web but in the end I can only understand things if they're explained in a language I can read [noparse]:)[/noparse]
Gr,
Mightor
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| What the world needs is more geniuses with humility, there are so few of us left.
| "Wait...if that was a compliment, why is my fist of death tingling?"
| - Alice from Dilbert
In the case of the servo signal line, a resistor is not needed. It is an output from the Propeller and input to the servo so there isn't a need for current limiting resistors. Beau likes to use a small value (100Ω or so) to limit crosstalk noise from the supply lines, but this is more for good measure rather than a necessity. For inputing 5V or bi-directional with a 5V signal, a resistor should always be used.
Thanks for that [noparse]:)[/noparse] At least now I don't have to resolder my proto board!
Gr,
Mightor
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| What the world needs is more geniuses with humility, there are so few of us left.
| "Wait...if that was a compliment, why is my fist of death tingling?"
| - Alice from Dilbert
W9GFO
Posts: 4,010
Comments
If you haven't read this (in the blue section of this forum, at top)
HOW TO SAFELY INTERFACE A 5V SIGNAL TO THE PROPELLER?,
it should explain much.
Basic rule is if over 3.3v, yes, to limit current use series resistor between Prop input and what it is receiving from
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Harley Shanko
h.a.s. designn
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E3 = Thought
http://folding.stanford.edu/·- Donating some CPU/GPU downtime just might lead to a cure for cancer! My team stats.
To my memory Parallax claims their Propeller outputs to be (nearly) shortcut safe, restricting the current to 30 - 40 mA. So it should be difficult to harm them. Another matter however is high current (> 1mA) input....
Do you need a resistor between a prop output pin and a servo signal line? If so, what value? Will a resistor in series not cause the 3.3V to be too low for the servo to "react" to a pulse if the prop fires it?
I read the HOWTO... thread but there is a serious amount of over-info in there that isn't really readable for people without a degree in electronic engineering such as myself.
A smaller HOWTO without a zillion posts in it would be a very welcome gift for those with merely an interest to tinker a little with the propeller without getting into the electronics side as deeply as some of you more professional lot [noparse]:)[/noparse] A couple of example circuits of how to hook up a few devices with different functions, such a servo, a ping sensor, that kind of thing. I know the prop is for more advanced users and I have no problems Reading The Fine Materials or searching the web but in the end I can only understand things if they're explained in a language I can read [noparse]:)[/noparse]
Gr,
Mightor
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
| What the world needs is more geniuses with humility, there are so few of us left.
| "Wait...if that was a compliment, why is my fist of death tingling?"
| - Alice from Dilbert
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Paul Baker
Propeller Applications Engineer
Parallax, Inc.
Thanks for that [noparse]:)[/noparse] At least now I don't have to resolder my proto board!
Gr,
Mightor
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
| What the world needs is more geniuses with humility, there are so few of us left.
| "Wait...if that was a compliment, why is my fist of death tingling?"
| - Alice from Dilbert