Wrong box detector

Hi all, sorry for my bad language .. It's my first time with Arduino and i need a really simple thing:

I do not want my employees err in charge of the tanks (chemicals). The red tank must be filled from the red cask and blue must be filled with the blue cask.

Now I want to insert a control into tanks, so if you approach the blue cask to the red tank, alarm begins to sound. Same for red / blue.

Any help or link to a tutorial ?

Realy thanks for the help.

What is the size of the casks ? and at what distance should they be detected ? RFID is for short distance. http://playground.arduino.cc/Learning/PRFID http://www.adafruit.com/categories/55

Thanks for the reply.

The casks are normal 5 lt.

The distance must be 20 cm.

Thanks for the links :)

I must say I haven't build one, but there are several simple projects using an RGB-led + photoresistor to detect the color of an object.

http://www.georgegardner.info/arduino/photoresistor-color-sensing-with-the-arduino.html

holy88: I do not want my employees err in charge of the tanks (chemicals). The red tank must be filled from the red cask and blue must be filled with the blue cask.

Now I want to insert a control into tanks, so if you approach the blue cask to the red tank, alarm begins to sound. Same for red / blue

Hi, I will say what everyone else is thinking. If so many of your employees are red/blue colour-blind, change the colour of the casks and tanks. If so many of your employees are stupid or careless, they should not be working with chemicals. If the chemicals are so dangerous, you need something more robust than an Arduino-based solution.

Perhaps you could say a little more about these chemicals. Nothing illegal I hope?

Paul

PaulRB:
Hi, I will say what everyone else is thinking. If so many of your employees are red/blue colour-blind, change the colour of the casks and tanks. If so many of your employees are stupid or careless, they should not be working with chemicals. If the chemicals are so dangerous, you need something more robust than an Arduino-based solution.

Perhaps you could say a little more about these chemicals. Nothing illegal I hope?

Paul

I agree with you. Nothing illegal for sure is just Chlorine and Acid. The problem is not the color, the problem are the employees for sure., but we can all make mistakes…

Idea:

Put NFC tags on the casks ( 5 lt ) with a string RED for NFC 1 BLUE for NFC2.

Arduino must be able to read the NFC tag and prevent the error with a sound if someone is trying to insert the Red cask ( NFC RED ) in the Blue tank and vice versa

I don't know whether the 5-liter containers are new and have a barcode printed on them. If you're able to find some PS2-barcode scanners, you can read 'm as PS2-keyboards with your arduino.

I'd go for chains with padlocks so that someone in authority.... that would be you..... chain each cask to the correct tank and have the chain length so that a cask cannot get close to the wrong tank. I'd have a log book certifying that the casks were chained correctly, cross-checked and initialed by someone else. Only you or your trusted 2ic have the keys.