Lost Item Tag project with Atmega328p + nrf24l01+

[builder01]

Hello,

I'm trying to do a similar "tag" device that buzzes everytime I press a push button at a distance. Like those that can be used to attach to things you are usually misplacing.

I have achieved most of the functionality with atmega328 + nrf24l01+.  I want to implement a loop in the RX that sets the NRF to power down for shorts periods of time; this is to manage the amount of time is looking for radio (power saving purposes).  I can send data by pressing an external push button to send a message ("ON") to RX , but after I set the NRF to go to sleep (setting the PWR_UP = 0 while on Standby-I), I wake it up by pressing the button and try sending another message, they don't get across anymore.

I have made sure that the CE is properly pulsed after shifting everything out of MOSI while sending that 2nd message after coming back from sleep. I really don't know how to debug this.

I have attached the code (including the library) for you to reproduce my problem if you want to help. The library is an slightly modified version of this one:
https://github.com/thehelvijs/nRF24L01-avr-bareminimum

Using TX and RX is simple with it and works quite well. My problem starts, as I said, when I try to send a message again after coming back from sleeping (setting nrf24_state(POWERDOWN) in the code to sleep).

Thanks in advance for your help!

[NiHaoMike]

Just attach RFID/NFC tags to the items and then use a reader to scan for them?

[builder01]

And how can I make them buzz from 20-30m away?