signal with a day long negative width.

Hi,

Long time lurker, third time poster. I have a question for you guys. I got a roomba and I hate having to tell it to go. I want to basically take a push button and convert it to automatically "press" once a day. I was thinking of soldering a 555 on to the traces as an astable vibrator with biasing to have it on for 1 second and have it off for a really really long time comparably(about 24 hours). Is there a more elegant way to implement this. It would have to be something simple because I will be soldering on to the traces.

needless to say, this is hard to test in a circuit capture program because of the abnomally long down time and short time up.

A 555 is not capable of generating such a long delay period. About the longest you can do with a 555 is about 30min.

Here is a previous thread that deals with a 24h delay.

An easy way to do long, accurate time periods, with short on-times. Electro-mechanical wall plug timers have a minimum of 15 minutes on or off periods. Digital timers have a minimum 1 minute. Adding a DC wall wart with a simple relay-monostable will do the trick. And the output is isolated from the line and DC supply. The on-time depends on the size of the electrolytic capacitor, the coil resistance of the relay, and it's pull-in and dropout voltages.

Actually you could do any type of monostable off the wall wart.

Ken

Oops!. A reread of the post looks like you want it built into the Rumba. Do it with an 8-pin PIC or equivalent microcontroller.