I made a project called 'Robot Arm with Electromagnet' that has been published here: http://fritzing.org/projects/robot-arm-with-electromagnet/
Arduino Uno with a program controls two servos and should controls the electromagnet in the and of the arm. If a switch is off then one can control the arm (only servos) with potentiometers. If a switch is on then the program controls the arm: two servos and electromagnet.
The schematic can be seen here: http://fritzing.org/media/projects/thumbs/sidebar/RobotKar2szervoval-2_schem.jpg
My problem is that that relay doesn't switch on/off the electromagnet. The electromagnet is always switched on.
I use the FRS1B relay and the 2N1613 transistor in the project.
The programcode can be downloaded from here: http://fritzing.org/media/fritzing-repo/projects/r/robot-arm-with-electromagnet/code/SantaKrisztianRobotkar_arduinoPrg.ino
Why doesn't work relay?
Regards, from Pál