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Re: LEGO MINDSTORMS EV3 Announced

Posted: 12 Jan 2013, 00:44
by aswin0
I rather have a internal clock than a gyro. And low power sleep mode.

Re: LEGO MINDSTORMS EV3 Announced

Posted: 12 Jan 2013, 20:10
by bernardborg
I agree an internal clock is extremely useful and I believe lego could try and fit it in ;) About the low power mode it is useful for us who hack and tweak with it imagine a robotic Internet appliance :)

Re: LEGO MINDSTORMS EV3 Announced

Posted: 13 Jan 2013, 09:45
by HaWe
I also agree that an internal clock is extremely useful.
But for continuous operations only a plug for an external power supply would be really rational (like, e.g., the RCX 1.0 once had).
But it's probaly too late to change anything any more.
(Like lots of more I/Os, e.g. 6 motors and 12 sensors or at least really chainable i2c up to 127 devices, what would have been wishful to have - or is it even already?)
my2ct.

ps:
BTW: has anybody read anything about i2c speed? 100k or even 400k bps?

Re: LEGO MINDSTORMS EV3 Announced

Posted: 13 Jan 2013, 11:48
by mightor
No official specs regarding the I2C specs have been released yet. Guess you'll just have to wait until they are :)

= Xander

Re: LEGO MINDSTORMS EV3 Announced

Posted: 13 Jan 2013, 12:17
by aswin0
Guess too that we have to wait ....... And speculate :-)

Xander writes on his site that the gyro and touch sensor have a sample rate of 1k. If this were true then these sensors must use i2c Fast mode + (fm+) or better. Fm+ has a bus speed of 1 MBits/s and a device ID mechanism. The latter would be consistent with the claim that EV3 recognizes the sensors attached to it.

Aswin

Re: LEGO MINDSTORMS EV3 Announced

Posted: 13 Jan 2013, 12:30
by HaWe
gyro and touch are probably analog (ADC)...?
but whatever, I'll wait, I only was curious...

Re: LEGO MINDSTORMS EV3 Announced

Posted: 13 Jan 2013, 14:09
by mightor
aswin0 wrote:If this were true then these sensors must use i2c Fast mode
So you are saying the new sensors use I2C? :) The only information that is out there is:
  • The new sensors use some sort of auto-id mechanism
  • The sensor ports are able to go up to about 200 kbit/s
  • The EV3 brick is backwards compatible with the "old" NXT sensors
There's nothing in there to suggest fast I2C :)

= Xander

Re: LEGO MINDSTORMS EV3 Announced

Posted: 13 Jan 2013, 16:53
by haydenstudios
I will never forget the day that I got on the LEGO MINDSTORMS website and saw the flash promotion introducing the NXT. It suddenly made the RCX look so old and outdated. The idea of more functional buttons, and an actual lcd screen instead of a numeric display, four sensor ports, and an actual speaker were absolutely revolutionary to me at the time. And now here we are, with that phasing out. Now the NXT starts looking almost old, and the EV3 so new. So it looks like our predictions for the name of the next brick were wrong, so much for FTR.

It's nice to now see four motor ports, but it bugs me that they're going back to what they did with the RIS and including one less motor than the number of ports the brick has, forcing you to buy another if you want to fill them all.
It's nice to see a higher resolution screen, faster speed, and I honestly was not expecting an SD card expansion slot. What strikes me as very interesting is that the infrared sensor appears to be capable of detecting both infrared signals, and motion. I'm a little bit disappointed that the new motors are so much like NXT motors in shape, because I was never fond of that design, as I always found them bulky and awkward. Despite being stronger and having built-in rotation sensors, I liked RCX motors better in a lot of ways. I'm curious as to how much stronger the new motors are if at all, and if the different third motor will have a rotation sensor. Seeing as how the EV3 has bluetooth, I'm not seeing why it wouldn't be able to communicate with the NXT.
mightor wrote:
schodet wrote:...and whether a new motor can be connected to an old NXT.
I don't know, I have not tried, but it's probably not something LEGO would really support :)

= Xander
I would bet $350 that that will work. I've gotten NXT motors to work on the RCX with a converter cable (even reliably enough to use it in one of my projects), and connecting new motors to the NXT looks even easier due to identical ports, so I'm as sure as Steve is that it would work.

Re: LEGO MINDSTORMS EV3 Announced

Posted: 13 Jan 2013, 18:07
by jwiger
haydenstudios wrote:... and if the different third motor will have a rotation sensor.
TLG refers to it as a servo, hence I'm sure it does.

Curious though how the encoder would work. Probably much like the NXT servos. Has anybody used two PF Servos with one NXT? I would be interested to see a 4x4x4 vehicle with selectable steering. This will be a boon for Truck Trials.

Re: LEGO MINDSTORMS EV3 Announced

Posted: 14 Jan 2013, 05:55
by mattallen37
I saw something that said the sensor ports support UART up to 460.8 kbps. My guess? UART and bit-banged I2C. 460.8kbps seems almost too fast to be bit-banged, but too slow to be HW. Most likely it's all bit-banged, and with the higher clock speed, bit-bang I2C could potentially reach to, or even beyond 100 kbps (default for the NXT was 9.6 kbps). However, in order to keep the communication backwards compatible, I2C will be 9.6 kbps, in order for the NXT ultrasonic sensor to communicate (although higher speeds for other I2C sensors should be an option).

From what I have read about the motors, they are simply DC motors with encoders. Unfortunately it seems as though they still haven't made a servo (at least not what I think of when I hear or use the term), or even a motor with absolute position sensing. Ideally they would use a magnet for absolute position sensing, which is possible (fingers crossed), considering the motors are said to have this new "auto-id" thing.

Philo did some tests with the NXT and PF-S. It worked fine, but it still only had 15 positions due to the internal HW setup of the PF-S.