I need to switch on my APC UPS at 2 AM and switch it off at 8 AM every day. Would like to switch on/off the mains power to the UPS too.
I am not an electronics guy, but started to learn and have built some basic circuits.
My initial plan was to build a timer based switch circuit, which when activated would switch on the UPS after a predefined (based upon value of resistor & capacitor and IC pin connections) time period (like 30 mins, 2 hrs etc.) and switch off the UPS after another predefined time period. The problem with this approach, I think is, somebody will have to switch on the circuit every day. My logic says, it must be possible to reset timer for every 24 hour or so. Can I?
The other approach was to build a programmable timer circuit, which will be always powered on, has a Real Time Clock, with battery backup and will power on/off the UPS and mains at the specified times. I have no experience with microcontrollers, but I can learn. Is this approach an over-kill?
The UPS powers my DSL modem and torrent box and is in a remote place and have remote hands (to activate the circuit if needed, in case of first approach) available at location till 11.30 PM
Please suggest which method is better or any alternative way.
Best Answer
Why do you need to turn off the actual ups? How about controlling the devices connected to it instead? Could you power off torrent server PC (assuming it's a PC) and configure the bios to turn it back on at a specified time? (Many BIOS'es have this feature built in.) or Wake-On-LAN can do something similar, and there are ways of routing WOL packets over the internet (a more advanced option).
alternately,you could toggle an electrical outlet using a Solid State Relay (readily available on eBay) rated for the voltage and load being attached, and control it with an Arduino or other microcontroller. I bet you could get accurate enough timing with Arduino that you wouldn't need a realtime clock module (RTC), but those are also available and can communicate with Arduino using SPI or I2C interface. With a SSR, you could leave the UPS on, and switch the power coming out of the UPS. To power up your server, many BIOS'es have the option to 'Power On' when power is restored after power loss. NOTE: be sure to properly shut down your server before killing the power to it, by initiating the proper shutdown command, to avoid corrupting your data.
I built an extension cord for 120VAC with a SSR tucked away inside the plug housing for about $25. It's easy to control with an Arduino or anything that can supply a 5VDC signal.
Hope this helps!