Mindboards

hi,
which commercial NXT-compatible i2c sensors can be connected altogether at 1 NXT port (by several portsplitters)?
For this purpose of course the internal pullups must be possible to be switched off and the i2c bus address has to be adjustable (at least / except one).
Has anybody got an overview of those "chainable" sensors?

Pretty much all of the ones made by Mindsensors. Keep in mind that power consumption per port becomes a problem when you do this.

- Xander

thanks, I heard of it. But pretty much of MS - which not?
And how are the pullups to be switched off? mechanically (e.g., jumper) or by software?

edit: which sensors of which companies can also be adjusted?

ps
to power consumption: you surely can plug an external battery supply via port splitter (4.3V or whatever to pin4/green), don't you?

You have to look at the user-guides to know for sure. Most of the digital sensors can be, but I know off the top of my head that the Numeric Pad for NXT, Realtime Clock for NXT, and Magic Wand can't be changed (at least not without hacking the HW).

For the sensors that support turning off the pullups, I'm fairly certain it's a SW thing.

Yes, you could use an external supply, but you shouldn't connect it right into the NXT sensor supply.

ok, that would mean to cut off the green wire coming from the brick...

it's really a pity that most NXT sensors don't match the i2c standard for up to 127 devices at each port - only mindsensors seems to.... :(

so what's left to be chainble :
the accelerometer (out of stock) ?
the PSP-interface ?
the distance sensors maybe ? ( but they are far too expensive if one wants to have a dozen or so...)


No other companies like e.g., dexter?

Well, the NXT itself doesn't really follow the I2C standards and LEGO only really designed the HW with a single sensor for each port in mind. So it is broken by design, so to speak. Some sensors work-around the design but strictly speaking they are not made according to LEGO's spec

- Xander

As long as it works...

again, what about Dexter sensors?

No, I am not aware of any I2C Dexter Industries sensors that allow you to disable the pull-ups. The RS485 based sensors obviously don't suffer from this issue

Xander

ok, so it's just MS left.
:(

Well, Dexters IMU combines 3 sensors on one, gyro, accelerometer and temperature.