I am trying to work with RobotC + PCF8574

and until now i can't do nothing with it...

The sample program on RobotC doesn't work for me and i really don't know why.

Anyone could help?

I would love to know how to use this thing, too. I have one but I have not used it yet.

Regards,
Xander

hi,
in our German forum we have a member who wrote a program with this PCF to connect a small keypad to the NXT:
http://www.mindstormsforum.de/viewtopic.php?t=2885

foto:

HTH!

Super toll! Thanks for the link, Ford

I am going to have to learn I2C if I am ever to mate my NXT with one of these babies:

It's a Propeller Proto Board, a test board with an 8 core uController (the Parallax Propeller) running at 80MHz. I have two robots powered by these. True multiprocessing I have a spare board, complete with VGA connector and 2xPS2 for keyboard and mouse.

Regards,
Xander

I'm glad if I could help!
I myself unfortunately am unable to solder anything - as we call it: I got "two left hands".

But for my neural net I'm looking for a sensor multiplexer for analog sensors, like 20 Touch or Sharp GP2D12 Sensors (<- THAT would be GREAT!)

Are you experienced for such a thing?

Well, I am not an expert, but I manage. The protoboard pictured above comes pre-assembled, so you don't need to do much to make it work. As for ADCs to suit your need, a friend of mine swears by the Maxim MAX127. It has something like 8 x 12bit analogue channels and a very nice I2C interface. They're a little pricey (about 15-20 euro) but you can order "product samples" for free from the website if you have some company address to send them to
Here is some more info on them: LINK.

As for soldering, why not get yourself a breadboard:

No need to solder then, I love those things. Once you have it all working, you stick it onto a proper board and solder it all together. Breadboards are very much in the Lego-spirit, put it together, play with it, then take it apart again.

Regards,
Xander

thx for the link, but I don't understand anything of those electronics... (otherwise I probably were even able to solder... )

Surely if you can wrap your brain around AI and NNs, you can figure out a small electronic circuit

Regards,
Xander

Hi Docilio

It looks like there could be a I2C bug in the last 2 beta releases, and I2C devices are not working. This could be the issue. Dicks working on that right now, so hang in there B-)

viewtopic.php?t=591

Scott

maybe, if I found the time to learn sth. about resistors and transistors and IC's (and English) - but the only thing I know is sth about mathmatics (besides my profession). Unfortunately, nobody is prefect - eehm: perfect.

lol poke fun at the moderator

Are you talking abnout minsdsenors unit?

I've used one a few times, what exactly are you trying to do with it?

Here's a sample to use as an input device:

typedef struct{
byte i2cMessageSize;
byte i2cDeviceAddress;
byte i2cWriteMessage;
} i2c_mess;



task main()
{
byte value[2];
int outputNumber;

byte cnt = 0;

SensorType[S1] = sensorI2CCustomFast;

i2c_mess ledArray;
ledArray.i2cMessageSize = 1;
ledArray.i2cDeviceAddress = 0x70;
ledArray.i2cWriteMessage = 0xFF;

while(1)
{
cnt++;
if (nI2CStatus[S1] == NO_ERR)
sendI2CMsg(S1,ledArray.i2cMessageSize,1); // set pins high for input
if (nI2CStatus[S1] == NO_ERR)
readI2CReply(S1, value[0],1); // read pins

outputNumber =(int) value[0];

nxtDisplayTextLine(4, "value %d", outputNumber);

}
}


I also have some out put samples at home I can post later on if you'd like.

If you built the mindsensors board you have to be careful that the address jumpers are set up correctly. And the documantation they have for it is wrong. They give you the adrressing for the PCF8574 but they give you the PCF8574A. The base address of the PCF8574A is 0x70.

I was thinking the same thing. =P

Somebody posted an I2cslave object for the propeller a few weeks ago. I haven't had a chance to try it yet.

I saw Hippy's post. I can't wait to try it out. So many things to play with, so little time! Thanks for the code for the mindsensors unit, btw.

Edit: Any code you might have, would be great! Please post whatever you [have|are willing to share].

Regards,
Xander