Hi. I want to buy a colour sensor and want to know, how to yuse it with RobotC.

Thanks

I think in its simplest form the Hitechnic color sensor can be configured as a standard "ultrasonic sensor". You don't get all the features but it is the easiest way to get started.

A full featured driver should be coming soon.

Hitechnic has posted how to use their color sensor

just go to http://www.hitechnic.com/ and click products, then the color sensor.

It provides how to use the sensor in sonar mode and the registers for I2C communication.

Here ya go

Unfortunately, the hitechnic is point back to this site for any reference! There is no sample code, or how to set the sensor register values.

Just program it as the ultrasonic sensor is unreliable. I tested it... it cannot tell the difference between green and black, or silver and white. Not better than a regular light sensor.

Then, in robolab, I used only red, or green, or blue channel. It only works sporadically. Any idea!?

You may want to check out this project for help, dtrotzjr has made some drivers to run many hitechnic sensors including the color sensor.

viewtopic.php?t=212

Hope this helps B-)
Scott

oh my God, do you really need that much RobotC code just to call a color sensor value ? ? ?
In Nxt-G it's JUST 1 BLOCK like all the others!

Why can't you get it like

The code is user made, and is his drivers for 4 sensors, its not all for 1 sensor.

The command you proposed is not quite practical, because to access the full functionality of the sensor, you need to use the I2C communication protocol. To get the values of the red, green, blue, you have to read different registry values on the sensor.

Remember, many I2C sensors have an analog mode where you can do just what you suggested:

setSensor (S1, sensorSONAR);
i=SensorValue(S1)

Scott B-)

Unfortunately, the "color number" is not precise enough to tell the following colors apart: hunter green vs green, silver(foil) vs white. Therefore you must read the next few bytes to get the red , green reading as well. Or, even with the raw values if they are not good enough.

Therefore:
readI2CReply(nDDPortIndex, nReplyBytes[0], 1);
should be changed to :
readI2CReply(nDDPortIndex, nReplyBytes[0], 4);

where nReplyBytes was declaried to be byte nReplyBytes[4];
.....................

I want to read in the 4 bytes startng from 0x42, because :

// since RobotC does not take "&" address syntax, I assume it will just read into the next 4 bytes.

--------------------

Unfortunately, all 4 bytes seem to get the same value!????


The point is that I need the precision. therefore, I want to read the reading for each color - at least red and green readings.

Idea????

Ahh, your problem is that the registry value returned from the color sensor is just one byte, and you are asking to return it 4 times, that is why you get the same value for all 4 replys.

What you need to do is read the red blue green light levels individually, there are different registry's just for these operations. The I2C registry numbers can be found at the bottom of the linked page. I believe you want registry's 43, 44, and 45. Registry 42 returns the color number that corresponds to the chart on the linked page.

http://www.hitechnic.com/contents/en-us/d18.html

Good Luck, hope this helps B-)
Scott

OOO!!! So, I have to send it 3 times if I want all 3 colors reading?

===============================
// to get the red reading

sOutput.nMsgSize = 2;
sOutput.nDeviceAddress = 0x02;
sOutput.nLocationPtr = 0x43;
sendI2CMsg(nDDPortIndex, sOutput.nMsgSize, 1);
..............

nDriverState[nDDPortIndex] = stateI2CPollWaitReply;
readI2CReply(nDDPortIndex, nReplyBytes[0], 1);

byte redvalue = nReplyBytes[0];
..............
====================================
// to get the green reading

sOutput.nMsgSize = 2;
sOutput.nDeviceAddress = 0x02;
sOutput.nLocationPtr = 0x44;
sendI2CMsg(nDDPortIndex, sOutput.nMsgSize, 1);
..............

nDriverState[nDDPortIndex] = stateI2CPollWaitReply;
readI2CReply(nDDPortIndex, nReplyBytes[0], 1);

byte greenvalue = nReplyBytes[0];
===============================================

So, if I want the, e.g., raw red reading.. I should :

sOutput.nMsgSize = 2;
sOutput.nDeviceAddress = 0x02;
sOutput.nLocationPtr = 0x46;
// 0x46 and 0x47 will store the raw red reading...

sendI2CMsg(nDDPortIndex, sOutput.nMsgSize, 1);
..............

nDriverState[nDDPortIndex] = stateI2CPollWaitReply;
readI2CReply(nDDPortIndex, nReplyWord, 2);

Word rawRedWalue = nReplyWord;
=======================================

I'm going to test it out now...

The I2C protocoll is much too complicate to handle. This really needs to be simplified a lot.
Why can't you implement a sensor protocol that allows some easy access to all sensors, equal if I/O, analog, or I2C?
In case of I2C returns mor than 1 value, an array or structure may be used, such as


As Dick Swan himself said, RobotC has been designed for beginners and novices.
An I2C protocoll is far too a low hardware- and bit-shifting level and appears to be more suitable for kind of professional embedded C programmers.

Novices and beginners need something like that 1 sensor block in NXT-G, but transfered to a convenient script language:

To get any sensor value, one line of RobotC code must fit!

hi,
glad to hear that it works!

But now for all the other RobotC programming beginners:
would you please be so kind and post your color sensor driver code to the forum "NXT Programming: Tips for Beginning with ROBOTC" ?
Maybe with an example how to initialize and use the interface routines?
Many thanks,
regards
Helmut