New Access Control System – Case Study Snapshot
- Company: Safehinge Primera
- Profile: Key manufacturer and supplier door set solutions and specialist products for mental health
- Project vertical: Mental Health Care
- Challenge: System needed to integrate into existing access control systems on customers sites, also needed to derisk the supply chain, lower the cost, improve battery life, gain international compliance, improve connectivity, and some other upgrades.
- Solution: Optimised access control system with new design from scratch.
- Services: Feasibility Study; Hardware Design (Schematic Design); PCB Design; Software Development; Firmware Development; Antenna Design Support.
- Impact: Unit now integrates effectively into access control systems onsite rather than having separate cards, De-risked due to IP owned in house, improved, internationally-compliant, and a 30% reduction in BOM costs. New design is also future-proofed and has opened up fresh market opportunities both in the UK and abroad.
Introduction
Founded in 2009 by Philip Ross and Martin Izod, Safehinge developed an innovative safety solution for doors, launching the Integral Finger Guard (Alumax) which is used to stop people being able to put their fingers into the hinge of a door and prevent them getting fingers trapped.
After the run-away success of this product Safehinge were in a position to purchase Primera Life who were the market leading manufacturers of anti-barricade locksets and other specialist door hardware widely used in Mental Health environments.
Over time, it became clear that there were several improvements that could be made to their product line and particularly the electronics for the wireless access control.
What are the challenges in access control system design?
Safehinge Primera had a device that handled access control, this was a separate system that didn’t integrate with the customers general access control and required separate setup, management and required staff to carry multiple cards which was creating niggles with some major clients.
The existing system transmitted the card details via bespoke 868 MHz and 915MHz radios to a controller. There were also supply chain issues, the relationship between the customer and the suppliers design team had stalled over difficulties from low battery life which was threatening the whole project. In addition, there were concerns over potential component obsolescence and what would happen if the supply chain were to be broken – a serious risk for any manufacturer.
Therefore, Safehinge Primera sought an experienced engineering team:
Able to futureproof the system to allow it to evolve in line with the requirements of end customers.
With extensive embedded systems design experience and a track record of delivering:
- Wireless battery powered devices
- Access control systems
Systems integration
Working to timelines and within budget
Who were responsive and communicated effectively
Capable of improving the product’s NFC performance
Who could implement in both 868MHz and 915MHz wireless communication bands into its new access control system design for international compliance
Solution – PCB layout, simulation and prototyping
ByteSnap provided Safehinge Primera with an improved hardware and firmware wireless solution for the access control system. This consisted of an updated IOL Board (Integrated Override Lockset Board), accompanying hub, and custom firmware.
The project was split into two parts: the feasibility study and the main development.
Feasibility Study
A technical investigation was carried out by ByteSnap through its Feasibility Study service. This was necessary to discover which wireless technology would be most appropriate for Safehinge Primera’s use case.
Technologies investigated:
- LoRa
- Wi-Fi
- BTLE
- 868 MHz (proprietary) / 915 MHz
There was also an investigation of access control interfaces:
Wiegand
A common interface for card reader to door controller communication in the industry, consisting of a common ground, D0 and D1. In addition to these signals, there is normally at least one LED signal going back to the card reader, if not more, and a buzzer.
OSDP (Open Supervised Device Protocol)
OSDP is a two-way communication standard developed by the SIA (Security Industry Association). It is designed to replace the use of the Wiegand interface, and offers several advantages, such as:
- 2-way communication
- functions such as updating the card reading device can be updated
- longer range due to the use of RS485
- encryption built into the protocol
APIs (Application Programming Interface)
This looked into the feasibility of having the hub part of the system communicate over an Ethernet interface to a server running security software which is already in use in the building that this product is being installed in. Some companies have their own APIs, for example VAPIX from Axis, with varying levels of access to end users.
However, an open industry standard named ONVIF (Open Network Video Interface Forum), is supported by many companies.
The product also needed to be updatable. For instance, in the case of an update to the API, or a new API being added. If it is required for the product to be able to interface with APIs of door control software, then any MCU (or SoC) chosen would need to support it, in addition to an Ethernet interface and possibly controller.
Investigations were also carried out to select the card reader module.
Once the feasibility study was complete, then it was onto the main project.
Main Development
Specification
The requirement from Safehinge Primera was that the market for this product would be international, so had to use both 868MHz (mainly used in Europe) and 915MHz (mainly used in the USA and Australia). Therefore, selection of the MCU was required to have the ability to use 868MHz and 915MHz. The antenna was also designed for use with both bands. This meant that Safehinge Primera could produce one set of hardware and still be internationally compliant.
With expandability in mind, an RS485 port was added to the hardware to future proof the device, in case Safehinge Primera and their customers sought the use of OSDP. This allows for the feature to be added via a firmware update, without replacing the hardware.
Safehinge Primera led the specification in collaboration with ByteSnap, in terms of how the user would interact, and what response the user would see, as well as when to do the error checking and what errors to check for. There was a requirement for a long battery life, so an NFC IC (Integrated Circuit) was selected, which had the capability to support this, by being off most of the time, detecting a field change to tell if a card has been presented, and only initiating communication at that point before going back to sleep.
Design
After the specification was made, ByteSnap moved onto designing the firmware and hardware in parallel. This was achieved by selecting the MCU and ICs, designing the hardware with the use of these selections and acquiring development boards for each of these components.
With the development boards, the implementation of the firmware could be tested on the target hardware, to identify any issues before the PCB build. The firmware starts with pseudo code, which should be easy to read and understand what the process is, and splitting it into tasks, for instance what the NFC IC should be doing, and what the LED state machine should look like. This splits down the complexity by turning the big tasks into little ones, and eventually becomes a “fill in the blanks” exercise.
A protocol was put into the specification to determine what data would be sent wirelessly between the IOL and hub. This included packets from the IOL such as requesting pairing, identification, access, and responses from the hub such as access granted, denied, error. Since both the IOL and Hub used the same processor, it was decided to design the implantation of the protocol among other things like the LED control into a common library, meaning that we could save time by keeping code that would be useful for both devices up to date in a common area.
There was no peripheral available for transmitting a Wiegand signal, so we had to use “bit banging”, where we control the logic level of the line manually via firmware, instead of just sending data to a peripheral e.g. UART, I2C, SPI.
ByteSnap eventually determined, together with Safehinge Primera, that Wiegand would be used as the communication interface due to the ubiquitousness and high level of documentation of the protocol.
ByteSnap’s engineers researched the protocol to confirm how it could be implemented within the system and efficiently integrated it as such, while maintaining a low power consumption. They then tested it on several major door controller brands, ensuring that it worked smoothly and error-free. As each of the other door controllers used the output signals in a different way, ByteSnap also delivered a solution featuring a universal method of deriving the response from these controllers in a way that ensured compatibility with most third-party door controllers.
Testing
A test plan was created early on in the project based on the specification. Throughout the project, the specification and testing documentation evolved as living documents, all within the initial project scope. The test plan, mostly focused on short term testing, was executed before each release of the firmware to Safehinge Primera.
Longer term testing was carried out by Safehinge Primera, where ByteSnap was asked to help design and produce firmware, software and a database, to view and test the battery life of a device in certain configurations over a longer period of time, as well as confirming the stability and robustness of the devices hardware and firmware.
Project Complexity
Particular areas of project complexity during the access control system design project included:
LPCD (Low Power Card Detect)
This detects when a credential is present by sleeping the majority of the time and waking up to read the load on the NFC coil (antenna.) If this load reading changes then it implies that a credential has been presented.
NFC antenna
The design initially had an on-board antenna. ByteSnap’s engineers then faced a challenge of the NFC antenna matching being not done as the same procedure as normal antenna matching. This led to the use of a third-party antenna.
The size constraints of the IOL proved to be a challenging environment for the NFC antenna, as well as the IOL being enclosed in a metal housing inhibited the frequency. The credential was not being detected within the required range. The ByteSnap team successfully overcame the issues by following a complicated tuning guide while the IOL was in the housing intended for it.
SDK (Software Development Kit) provided with the MCU
The SDK included a sleep mode, where the MCU would stop the main high-speed clock of the processor and turning off peripherals, thus saving power.
During long term testing at Safehinge Primera, there was an issue seen after a certain time (~37 hours), where the IOL would no longer go into its sleep mode properly. This turned out to be a bug with one of the timers in the SDK, that would block the MCU from going to sleep. ByteSnap successfully resolved this by updating the SDK.
Project Conclusion & delivery
ByteSnap provides technical ongoing support to Safehinge Primera, together with appropriate development choices the future direction of the product.
Key Achievements
ByteSnap Design has a strong history within the embedded industry, and the team at Safehinge Primera entrusted ByteSnap engineers to deliver changes and modifications, where necessary, on time and with low risk.
Project benefits include:
- The new design allows these doors to be setup like any other door on a Paxton (or similar) access control system which are already in use by most of the customers for this product.
- The IP for this design has been transferred from ByteSnap to Safehinge Primera meaning they have complete control of the supply chain and are not tied to any manufacturer. Safehinge Primera also has full control to add features or integrate with any other system in the future if required.
- The build cost of this is considerably lower than the cost of purchasing elements of the original system from a third party.
- Significantly upgraded new access control system design. The new IOL board now has an estimated 3.3 years battery life based on 50 lock cycles daily.
- Improved energy efficiency: The significant increase in battery life not only meets but exceeds client expectations, potentially reducing maintenance costs and environmental impact
- Futureproofing has been built in to the new IOL board with peripherals added for expansion of functionality later down the line, to evolve with the needs and budgets of Safehinge Primera’s clients.
- Enhanced international compliance: The redesigned system now supports both 868MHz and 915MHz wireless communication bands, enabling Safehinge Primera to expand into global markets
- Improved connectivity: The updated system features better NFC performance and wireless communication capabilities, enhancing overall functionality
- Increased market share: The improved product has enabled Safehinge Primera to grow their market share in the access control systems sector for vulnerable environments
- Streamlined development process: ByteSnap’s expertise and responsiveness helped overcome various technical challenges, reducing overall development time and costs
