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Future Electronics has developed the Tap It Keychain which demonstrates how easy it is to work with NXP’s LPC8N04. To showcase the simplicity of designing with this MCU, the Tap It demo tracks the physical condition of a package – namely temperature, humidity and physical shock. For the user to retrieve the data, they simply use a smart device, tap and read the data using NFC.

NFC Tap It Keychain How To
  1. Install and run an NFC reader on your NFC capable smart device.
  2. On Android, use the NXP LPC8N04 NFC Demo (or any NFC reading App of your choice)


    and iOS (only iPhone 7 and up with iOS 11)


  3. If you are using the NXP App, make sure you are on this screen. Read NDEF is in blue.

  4. Insert the CR2032 coin cell in the Keychain. Positive side facing up.
  5. Make sure the SW2 switch is in the BATT position.
  6. An LED will start flashing.
  7. Tap your smart device on the keychain.
  8. The App will show the temperature and humidity data as well as the number of shakes events (Shake #) it has recorded thus far.
  9. Shake it side to side vigorously to record an event. LED will flash rapidly 5 times to confirm detection of event.
  10. Write “CLRLOG” in android app using “Write NDEF” to clear all records. This function is not available on iOS app.
  11. Press and hold SW1 for 5 seconds to go into sleep mode. (Enters sleep mode when there is no operation for 2 minutes).
  12. You can wake it up either by using the SW1 or NFC.
  13. Once done, flip the SW2 switch to SWD position to preserve battery life.


Data Recording in Running vs Sleep Modes

The keychain has two modes which are described below.

Running Mode (LED Blinks) Sleep Mode (LED stop blinking)
Records environmental data every 2 seconds Records data every 60 seconds, then goes back to sleep
Records shake when unit detects shake Records shake, then goes back to sleep


NFC Tap It Keychain Block Diagram

The following parts are used in the keychain.


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