A friend has asked me to make a “Grounding box” for her. Her plan is kids stuff up, cellphones go in the box.
brainstorming a few ideas now i’m overwhelmed of possibilities, hoping that some of you a little more experienced can tell me what direction i can head in.
Lock box on a timer, set timer Days:Hours:Mins:Sec.
Timer will display time left when timer runs out it unlocks. (servo lock)
2 leds to indicate lock state.
3x4 keypad for anytime over ride (and setting the timer)
box will re-lock after X mins automatically. (they are ment to be home at 4 if they not home at 4, no phones)
Can this even be done ideas:
give it a sim card, if the wrong code is entered it sends a text, if the correct code is entered it sends a text (keypad is for override only)
can text commands (unlock for 20mins then re-lock and continue timer, add time, remove time)
wifi connected with a PHP/web interface.
I was thinking about using arduino but the more i think about it, the more features i would like to add i have never played with arduino and not even sure if it can do all of those tricks at once.
If it was me, I’d either use an Arduino and a JY-MCU bluetooth serial module( under $7 )
or you could maybe even skip both of those, and just use a cheap esp8266 wifi module. ( it’s got a cpu, some i/o, and wifi, all included for $5ish ).
in either case, the cpu can have it’s count-down timer and/or internal clock set from a mobile phone, or a PC , whatever ( with bluetooth, or wifi, doesn’t really matter). Ie this happens from a “master device” - which is your phone, not the kids, obviously. I’d skip the keypad, just use the “master device” ( a phone that’s not inside the box, and is paired to the bluetooth or wifi etc) to do a “remote open”. if you use the esp8266, you can have it send status update/s and/or get instructions from a web server ( ie php code) , which would mean you could upen/close it from anywhere in the world.
Might want to consider using one for the pins to drive a mosfet to power the servo. They tend to use alot of power when not moving… And i assume you would have no way into the box when the power goes out. instlaling a power plug with a diode rectifier might be worth a thought.
I’m interested in seeing how this project comes along
put the cat in there too… with vial of… oh hang on… wrong kind of box experiment.
It reminds me of a ‘reverse’ geocache box I saw a couple of years back, when the box arrived at a certain place according to the GPS module attached to an arduino it would unlock. You could check how far you were from the destination location by pressing a button, but you were only able to check a certain number of times before you would ‘lose’ and not get the box open. I think someone also used a box like that for a marriage proposal, when it was a particular location they could open it to receive the ring.
Googling that box might give you some hints as to how to get started with the box.
I think the tamper alert/indicator is a good idea.