Future Electronics — NFC Tap It Keychain

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) Click here for Android

    

   and iOS (only iPhone 7 and up with iOS 11) Click here for iOS

    

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.

NFC Tap It Keychain Block Diagram

The following parts are used in the keychain.
 

LPC8N04 is a cost-effective MCU which serves as an entry-level connectivity solution for embedded applications with integrated NFC connectivity. The LPC8N04 MCU contains multiple features, including several power-down modes and a selectable CPU frequency of up to 8 MHz for ultra-low power consumption. The peripheral complement of the LPC8N04 MCU includes 32 kB of flash memory, 8 kB of SRAM, 4 kB of EEPROM, one I2C, one SPI/SSP, and up to 12 general purposes I/O pins.

The NXP® MMA8652FC 12-bit accelerometer has industry-leading performance in a small package. It is packed with embedded functions that include:

• Flexible user-programmable options and two configurable interrupt pins
• Overall power savings through inertial wake-up interrupt signals that monitor events and remain in a low-power mode during periods of inactivity

The Adesto® AT25SF041 is a serial interface Flash memory device designed for use in a wide variety of high-volume consumer based applications in which program code is shadowed from Flash memory into embedded or external RAM for execution.

The IDT HS3003 is a highly-accurate, fully-calibrated relative humidity and temperature sensor. The high accuracy, fast measurement response time, and long-term stability, along with the small package size, makes the HS3003 ideal for a wide range of applications from portable uses to harsh environments.