On Fri, Jan 9, 2015 at 1:02 AM, <[email protected]> wrote: > Hi ! > I have IOIO board where the VREG is damaged, so it cannot be powered > normally (5-15V through VREG). As Ytai suggested it can be powered directly > through 5V pin. If I have 7.4V Lipo battery, is it ok to connect it to this > 5V pin using appropriate resistor to cut the voltage down to 5V ? >
There is no "appropriate resistor" to do this. What you need is a voltage regulator. > If I connect a LED to some digital output (3.3V) should I use a resistor > to protect the LED (I noticed that the LEDs may be damaged shortly after > use) ? > The resistor is setting the current (which would otherwise be infinite, ideally) and is mostly to protect the IOIO more than the LED. If you ever connected the LED without the resistor there's a fair chance you've damaged the IOIO. > Also I have noticed that (when the VREG was OK) standard servos could not > be powered from the 5V pin through VREG, this will damage the VREG ! The > servos must be powered externally from 7.4V Lipo. > This should not be the case. The IOIO-OTG has a 3A regulator and the IOIO v1 had a 1.5A regulator, which would be way enough for at least 2 standard servos. The voltage regulator is also protected against over-current, so the worst thing that can happen is that the IOIO would reboot. The only failure mode I'm currently aware of has to do with a rather high (>12V) input voltage and heavy current loads. > I think that the 3 and 5V pin cannot be used anything except for powering > LEDs, > As above, this is definitely incorrect. > I have a relay (control 5V 85mA) how this should be powered and connected, > not to damage the IOIO board ? > A transistor is the easiest way. For beginners I'd recommend a NPN, such as 2N2222, with the IOIO pin connected through a 470 ohm resistor to the base, the emitter to GND and the collector to the negative side of the relay coil (or any of the legs if not polarized). The other leg of the relay coil goes to 5V. Setting the pin high will actuate the relay. > What about ESC (speed controller) powering ? > Those typically can and should be powered by higher voltage than 5V. If that's the case, connect is to Vin. Otherwise, if 5V is desired there's no reason not to use the IOIO on-board regulator as long as the current draw of the ESC is within specification (that is, a small-ish brushless motor should be fine). > > Currently I have one working IOIO, one with VREG off, and one totally down > ... > Cheer up: the process of learning electronics via experimenting involves frying some chips. Try to understand what had happened and how you can prevent it in the future. > > > -- > You received this message because you are subscribed to the Google Groups > "ioio-users" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To post to this group, send email to [email protected]. > Visit this group at http://groups.google.com/group/ioio-users. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "ioio-users" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/ioio-users. For more options, visit https://groups.google.com/d/optout.
