Send out a short signal every 10 seconds to an arduino In order to reduce power consumption, I want to resume my Arduino from standby mode every 10 seconds. For this a hardware interrupt is necessary.

Is there such a device that can create a quick impulse to trigger that interrupt? It can be anything from 10ms to 2 seconds; doesn't matter. My first thought was to use a 555 timer, but this one can only be on for 10 seconds and off for the same amount of time.

The best solution for me would be an already assembled device that I just have to wire with my Arduino since my knowledge in electronics is very low. Or a detailed assembly plan, then I would be able to build it myself I guess?

UPDATE: I was now able to put the Arduino into standby-mode using the Low-Power library. At first it seemed like it didn't work, because I wanted to print out a text over the serial connection. Instead, I tried to let the internal LED blink every 8 seconds, and this works perfectly.
A 555 doesn't have to generate a 50% duty cycle. Even if you do want to use a 50% duty cycle, the edge can be RC coupled into the interrupt to reduce the pulse width.

An Arduino can use a slow clock like a 32kHz watch crystal, then it's very low power indeed. This slow one can be used to wake-up your more power-hungry Arduino.

The lowest power and tidiest external solution would be to use a CD4060. These are designed to be very low power, very long period timing devices.

The correct way to do it is to use the internal Watchdog Timer to wake itself up from sleep. This uses an independent internal hardware 128kHz low power oscillator. The longest this can be programmed to wait is 8s. However, if you program it to 5s, then the Arduino can choose to do work, or go straight back to sleep again, on each interrupt.