RoboSavvy Forum

Audrino board

2007-03-08T21:24:44+01:00

That's more or less what I'm doing, although because the single axis gyro is a 5-volt part, AREF has to be 5 volts. But I am using a "standard" LDO 3.3 volt regulator to provide power for the 5-axis board, and I'm just feeding the analog lines into the 5 volt A/D pins on the ATmega168. I lose almost one bit of resolution that way, but we're not using these IMUs for navigation - we're using them for balance, so even 9 bits should be good enough.

- Jon

Statistics: Posted by JonHylands — Thu Mar 08, 2007 9:24 pm

Audrino board

2007-03-08T16:25:05+01:00

JonHylands wrote:
The single-axis gyro board that Sparkfun sells (the analog ADXRS series) runs off 5 volts, so you could at least test using it.

You could also use one of these:
http://www.sparkfun.com/commerce/product_info.php?products_id=849
which is a 5 volt 2-axis accelerometer that outputs analog voltages.
- Jon

Another thing i havent tried but should work is to provide the Atmega pin called AREF with a voltage of 3.3V same as the voltage powering the sensor boards. So the Atmega would be powered by 5V but the AREF and the sensor boards can be powered by 3.3V.
The advantage of this is that you can use a cheap ($0.5) voltage regulator since the gyro/accelerometer dont consume lots of power.

Statistics: Posted by limor — Thu Mar 08, 2007 4:25 pm

Audrino board

2007-03-08T15:02:03+01:00

pepperm wrote:
JonHylands wrote:So, in order to use this board with the bioloid bus (which can go up to 12 volts when its plugged in), you would need an off-board regulator to provide 5 volts.

- Jon

Maybe just change the cap, or remove it and put another on a daughter board across the AX-12 3 pin connector supply pins.

This board looks great, pretty much like the Orangutan but without the motor drive IC that we don't need.

Do you have any in stock yet Limor and how much would they be please?

I'll look at a daughter board.

Mark

It will take a couple of weeks to receive the Audrino Mini boards from Sparkfun. The cost at RoboSavvy Store will probably end up being around 25GBP (inc. VAT).

Statistics: Posted by limor — Thu Mar 08, 2007 3:02 pm

Audrino board

2007-03-07T22:52:55+01:00

I've just looked at the Arduino Mini schematic and the only capacitor on the input supply line is a 100nF decoupling capacitor. These usually have high voltage tolerances. The only low voltage rated capacitor is a 10uF 6V one across the regulated 5V supply. So I think this board should run off the CM-5 supply. The regulator may get hot though.

I'd love to try one all the same. At Sparkfun they are $36 which is about $5 dearer that the Orangutan but if it is available on Robosavvy that would be great.

We could use the boot loader too.

Mark

Statistics: Posted by pepperm — Wed Mar 07, 2007 10:52 pm

Audrino board

2007-03-07T22:34:45+01:00

JonHylands wrote:
So, in order to use this board with the bioloid bus (which can go up to 12 volts when its plugged in), you would need an off-board regulator to provide 5 volts.

- Jon

Maybe just change the cap, or remove it and put another on a daughter board across the AX-12 3 pin connector supply pins.

This board looks great, pretty much like the Orangutan but without the motor drive IC that we don't need.

Do you have any in stock yet Limor and how much would they be please?

I'll look at a daughter board.

Mark

Statistics: Posted by pepperm — Wed Mar 07, 2007 10:34 pm

Audrino board

2007-03-07T16:28:06+01:00

I talked to my brother again this morning regarding this board - it apparently has a big low ESR cap on the bottom of the board, which is only rated for 10v.

So, in order to use this board with the bioloid bus (which can go up to 12 volts when its plugged in), you would need an off-board regulator to provide 5 volts.

- Jon

Statistics: Posted by JonHylands — Wed Mar 07, 2007 4:28 pm

Audrino board

2007-03-07T13:23:00+01:00

The board uses this voltage regulator:

LP2985AIM5-5.0 (there appears to be a typo in the schematic).

which, according to the data sheet for the regulator, can handle 16 volts max. I'm not sure why they say 9 volts max...

My brother took my code last night and loaded into his Arduino Stamp, and successfully toggled the LED (hooked to D3) using the bus WRITE_DATA commands.

The single-axis gyro board that Sparkfun sells (the analog ADXRS series) runs off 5 volts, so you could at least test using it.

You could also use one of these:

http://www.sparkfun.com/commerce/product_info.php?products_id=849

which is a 5 volt 2-axis accelerometer that outputs analog voltages.

- Jon

Statistics: Posted by JonHylands — Wed Mar 07, 2007 1:23 pm

Audrino board

2007-03-07T11:23:27+01:00

Statistics: Posted by limor — Wed Mar 07, 2007 11:23 am

Audrino board

2007-03-07T10:45:31+01:00

JonHylands wrote:
My brother pointed out that the Arduino Stamp comes with a 16 MHz crystal, so it should be compatible with using it as a bioloid sensor...
http://www.sparkfun.com/commerce/product_info.php?products_id=8164
- Jon

Don't know how I missed out on this module. RoboSavvy is a Sparkfun dealer (first shipment arriving today) so it would be great if this board can work as "the" Bioloid sensor board. On their site it says that the Audrino board can be powered by 9V input. Does it mean that it can tollerate the Bioloid bus power?
It regulates the power to 5V so it means that the gyro/accellerometers found on sparkfun can not be powered by its regulator since they are 3V.

Statistics: Posted by limor — Wed Mar 07, 2007 10:45 am