ChApTEr 2 ■ hArdwArE for IoT SoluTIonS
The shield also has a MicroSD reader, making it a good choice for me since many of my Arduino nodes
use the SD card to store data for logging and as a backup for database storage. Figure 2-21 shows the Adafruit
WiFi shield.
Unfortunately, this shield is not compatible with the Ethernet library, which can mean rewriting the
networking portion of your existing sketches. This makes it less attractive for me when developing IOT nodes
because I like to use Ethernet connections when developing my sketches to eliminate the delay inherent in
slower WiFi connections.
Sparkfun CryptoShield
This shield is an interesting shield. It is the first I’ve found that includes advanced cryptography features
such as a real-time clock (RTC) module to keep accurate time, a trusted platform module (TPM) for RSA
encryption/decryption, an AES-128 encrypted EEPROM for storing small amounts of encrypted data
(such as user IDs and passwords for servers), support for SHA-256 and HMAC-256, and an ATECC108 that
Figure 2-21. Arduino