ZYMKEY and HSM security modules feature two independent perimeter circuits that can be configured to detect physical tamper intrusion events.
Each perimeter loop should be connected with a 30 AWG wire or thicker and nominal length of 2 feet. For longer lengths contact Zymbit. The wire should be electrically insulated for all applications. A shielded cable may be necessary for electrically noisy or industrial applications.
Physical Circuit Connections
How these circuits are configured physically will vary depending upon the specific application, enclosure and security needs. Standard wires, custom flex PCBs and rigid PCBs may all be used to complete a perimeter loop circuit.
Here we share some practical examples of how to configure perimeter detect circuits for different applications and equipment.
To learn about software configuration and use of perimeter detect functions Learn more>
Direct Connect to HSM4 Hat
HSM4 HAT provides four pin header and FPC connectors to interface to perimeter circuits 1 and 2. This is convenient for rapid prototyping and small scale production situations.
For high volume applications, different connector types are available - contact zymbit for more details.
Perimeter HDR (Header) Pinout
Perimeter FPC (Flexible Printed Circuit) Pinout
HSM Direct Connector - Hirose Header DF40HC(3.5)-30DS-0.4V(51)
Direct Cable Connect to Zymkey 4i
Perimeter circuits on Zymbit 4i are accessed from a standard microUSB connector.
Use a standard microUSB extension cable to close circuits P1 and P2 as follows.
Adapter Connect to Zymkey 4i.
Several adapters are available from Zymbit that simplify connection from the microUSB to header and FPC. These are convenient for development. Buy Adapters >
Flexible Security Shield Wrapping RPi4
HSM4 Security Module, fitted to PiHat1. Flex circuit connects to FPC connector on HAT
Rigid Security Shield installed on ProtoKit4
A printed circuit shield is fitted into the lid of the ProtoKit 4 and pogo pins connect the top mesh to the the bottom board. When the lid is closed, the circuit is closed.
The shield connects the following four perimeter signals available on the protoboard:
FlexCable Wrap with PiZero Hat
SDCard Blocking Perimeter Adapter with PiZero Hat
Tamper Switches & FlexCable with Secure Compute Device
Zymbit secure compute motherboard for RPi
Internal Tamper Switches