Need help with RobotShop Perimeter Wire Generator and Sensor Soldering Kit

[tazdar]

Hi,

I’m a beginner when it comes to hardware. I just assembled the RobotShop Perimeter Wire Generator and Sensor Soldering Kit. The waveform generated by the 555 board looks odd on my scope. I have checked all the caps and resistors and everything looks right. Im using a new 9v battery to power with and a 8ft piece of 18 awg wire.

Anyone know what would cause the 555 to output a signal like this:

Thanks for the help,

Alex

[tazdar]

Here is a pic of the assembled 555 board.

[tazdar]

Ah, my fault. I thought I was probing across the current limiting resistor but I was not. The waveform is normal.