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I'm pretty new to electronics and microcontrollers, and I've gotten a netduino because I wanted to get into this topic, and so after a few starting excercises (like blinking leds, using shift registers with SPI, using LDRs as sensors and so on) I think about setting off to my first "real" project: a small lego robot (built with old parts that I used to play with a long time ago ). There are, at this moment, two things unclear to me yet though, so if anybody could clear those up for me that would be great:
I'm going to run this robot on batteries, and i'm wondering if directly plugging in a 9v battery to Vin/Ground (maybe with a rectifying diode to prevent wrong polarization) will be fine, or if i need a supply with a regulated voltage (which would probably need a bigger voltage on the battery, which i'd like to avoid - i'm already going to have to use 8 AA batteries to power the motors).
In which state are the netduino pins when the netduino turns on? Or, to be more direct: Can I damage the netduino when I connect a pin to the netduinos 3.3V on startup? (If it's going to be used as an input with ResistorMode.PullUp later).
Thanks for your help, and for a great product
Stefan
I believe that no discovery of fact, however trivial, can be wholly useless to the race, and that no trumpeting of falsehood, however virtuous in intent, can be anything but vicious.
-- H.L. Mencken, "What I Believe"
Hi Stefan,
You can supply 7.5V-12VDC to the VIN pin, unregulated. A 9V battery will work fine. In fact, we do that frequently with the Netduino Minis.
As for startup--the pins are set as inputs with pull-ups enabled by the micro at boot. This may cause attached devices to see a bit of a "logic high" during boot, but you should haven't to worry about damaging the Netduino itself during boot unless you're trying to draw/supply large amounts of current.
For your motors and such, your best bet is to use a separate power supply.
Chris
Hi Stefan,
Welcome to the forums!
Connecting a battery to the Vin and Gnd will be fine, as long as it's between 7.5 ans 12V.
You can't damage the Netduino if stuff is connected to it on power on. While the Netduino boots, all ports have a bit of current for a second though.
Kind regards,
Stefan
You can supply 7.5V-12VDC to the VIN pin, unregulated. A 9V battery will work fine. In fact, we do that frequently with the Netduino Minis.
As for startup--the pins are set as inputs with pull-ups enabled by the micro at boot. This may cause attached devices to see a bit of a "logic high" during boot, but you should haven't to worry about damaging the Netduino itself during boot unless you're trying to draw/supply large amounts of current.
For your motors and such, your best bet is to use a separate power supply.
Chris
Yes, I planned to use a seperate block of batteries for the motors, using an H-Bridge, i got as much from the web. Thanks to you and Stefan for the information!
I believe that no discovery of fact, however trivial, can be wholly useless to the race, and that no trumpeting of falsehood, however virtuous in intent, can be anything but vicious.
-- H.L. Mencken, "What I Believe"
Yes, I planned to use a seperate block of batteries for the motors, using an H-Bridge, i got as much from the web. Thanks to you and Stefan for the information!
I used such a bridge for my robot, see this thread for more. Perhaps the code could be of use for you?
Just a question Stefan W...
What kind of motors are you using with the lego? the originals ones?
If so, how do you solved the wiring of them (the plain special connectors I mean)?
Cheers
Biggest fault of Netduino? It runs by electricity.
Just a question Stefan W...
What kind of motors are you using with the lego? the originals ones?
If so, how do you solved the wiring of them (the plain special connectors I mean)?
Cheers
I did not yet, but I planned on cutting a lego cable open (i have a damaged one anyway) and soldering it to hookup wire. When i'm done, i'll report on how it worked out - and yes, original lego motors (the ones that i have now are the old ungeared ones, i ordered some newer ones from ebay).
I believe that no discovery of fact, however trivial, can be wholly useless to the race, and that no trumpeting of falsehood, however virtuous in intent, can be anything but vicious.
-- H.L. Mencken, "What I Believe"
I used such a bridge for my robot, see this thread for more. Perhaps the code could be of use for you?
I'll have a look into it when I run into trouble, but for now this is my learn-as-you-go project - thanks though
I believe that no discovery of fact, however trivial, can be wholly useless to the race, and that no trumpeting of falsehood, however virtuous in intent, can be anything but vicious.
-- H.L. Mencken, "What I Believe"
). There are, at this moment, two things unclear to me yet though, so if anybody could clear those up for me that would be great:
