One those amazon thingies that talk to you and take over your life
Arduino plus RTC (Real Time Clock) module. About a fiver for a clone nano arduino and a few quid for the RTC clock. You'll need a battery for the RTC, CR2032 is usual and a power source for the arduino. Add a small piezo speaker and you can make irritating tones to your heart's delight (and victim's insanity)
A better option is noises at random intervals
Far more irritating.
Make it waterproof.
I'd drop it in a bucket of water to stop it, if it was me on the receiving end.
One those amazon thingies that talk to you and take over your life
This is a cheap amp kit, will require power and a source to play selected music.
https://www.ebay.co.uk/itm/193646055257
I’ve used quite a few of this type in the past. Currently running a 2.1 amp kit in the office. It’s very good
That looks ideal...
ive got a spare one you can have for nothing, but it requires a 36v power supply
another late night eBay purchase
What's to stop the recipient just picking it up, and taking it a long way from home?