How to Provide Secure Tracking and Validation in Attachable/Add-On Peripherals (Part 1)

By Erik Fasnacht

Applications Engineer

Microchip Technology

By Matt Whitcombe

Microchip Technology

March 24, 2022

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How to Provide Secure Tracking and Validation in Attachable/Add-On Peripherals (Part 1)

Many electrical or electronic products require separate, replaceable refills or accessories during their useful life. These add-on items could include electronic as well as non-electronic devices. The safe and effective use of the main, electronic system depends upon the compatibility and proper usage of the two components. This is especially true in medical applications as COVID-19 increases the need for greater safety.

Validating and tracking added accessories is critical to prevent re-use, contamination and to avoid exceeding the useful shelf-life of these accessories. Improper and excessive overuse can also damage and even void the warranty of the more expensive host. A single-wire serial EEPROM with a factory-programmed 64-bit serial number provides a low-cost, space-sensitive solution for validation and tracking in medical and several other applications. It can also provide a key for external data encryption/decryption for security. With a single-wire memory device, validation and tracking can be easily implemented in new or updated designs.

Part one of this article describes a high-level overview of why would tracking and identification be needed on a product. Part two describes in detail the technicalities of how tracking and identification may be added to an attachable or add-on peripheral.

Applications for Identification and Tracking                          

In general, applications that could benefit from identification and tracking are replaceable cartridges, connectors, peripherals and consumer tools. More specifically, Table 1 lists several applications that could use identification (ID) and tracking.

Table 1. Potential Applications for Single-Wire Memory

The reasons for adding ID and tracking to these and other applications can range from simple identification to changing the function of an electronic device based on the attachment. The following list shows the type of information that can be provided by electrical as well as non-electrical attachments.

Benefits and Information Stored with Single-Wire Memory:

  • Serial numbers
  • Tracking information
  • Attachment description
  • Usage records
  • Consumption counts
  • Counterfeit protection

For example, in medical equipment, a syringe pump with a single-wire memory device can identify what is in the syringe and what the dose should be as well as prevent re-use and provide expiry date and additional tracking information.

Advantages of a Single-Wire Memory Device:

  • Easy to implement
  • One data signal and ground return
  • Relatively low cost
  • Mid-range security
  • Minimized connector pin count which also saves cost
  • Alternative to radio frequency identification (RFID) and a more expensive RFID receiver

Single-Use Medical Applications                                                               

There is a trend in the medical market to shift diagnostic testing away from centralized labs in hospitals to rapid, point-of-care diagnostics, remote diagnostics, doctor’s office or clinic facilities. For single use testing, single-wire memory provides an ideal means of implementing the type of information many medical device manufacturers want to associate with their products. Point-of-care diagnostics provide a greener solution since they avoid or reduce the need to transport samples to a central testing lab or a hospital. These diagnostic tests typically use disposable products for many purposes. In contrast to disposable products, reusable medical devices are typically more expensive, much larger and require sterilization for re-use --- a process that is much more difficult to safely implement in addition to the cost and complexity of managing reusable devices.

Medical applications can include electronic items but also non-electronic items since single-wire memory requires no additional electronics assembly. Companies that make electronic as well as companies that make non-electronic medical devices can benefit from the ability to easily add desired and even critical information to their products.

Knowledge that a product has not been tampered with is very important in medical device attachment. A disposable medical device with stored calibration information and an indication of usage in single-wire memory could also store lot codes and indicate time or the need to replace. For example, an oxygen mask that has no electronics in it at all still needs to indicate to a healthcare nurse that the device is: (a) plugged in and (b) that it has not been used before. A single-wire memory device provides a simple solution that can be molded into the plastic of the product.

With COVID-19, polymerase chain reaction (PCR) testing, and similar techniques are being explored for their effectiveness in detecting the presence or absence of the virus. Cartridge-based sample analysis for quantitative (micro PCR) analysis in disposable, portable applications can benefit from using single-wire memory. In addition, sampling blood (serum and plasm) and non-invasive saliva, as well as liquid and solid body materials are all potential candidates for medical analysis with a disposable test attachment.

DNA testing is an excellent example of a medical point-of-care application of single-wire memory.  With the appropriate sample in the sample well, the machine provides timely DNA results directly to the machine operator. The chemistry in this application needs to store items such as calibration data, whether it has been used once already and more. The single-wire memory device could contain Lot ID / serial number, calibration table with data, test identifier, re-use lock and expiry date. Figure 1 shows the attachment of a medical sample to an analysis machine.

Figure 1. Point of care diagnostics are facilitated by the right medical tool and its associated attachments.

Additional medical applications for single-wire memory are medical devices using a disposable plastic tube that needs to be tracked. When a new plastic tube is installed, it must be assigned to and stay with each patient who uses the device. In some instances, a machine may need to be shared with other patients. For safe usage, the device needs to reconfirm the tube identity on each insertion and read the tube usage history. The tube’s memory needs to track items such as patient ID number, timestamps for when it was used and possibly other data. Figure 2 shows how the disposable product can contain this information.

Figure 2. Tracking of important and critical information in a disposable medical product is enabled by a single-wire memory device.

There are several non-medical disposable applications for this type of small volume memory storage. For example, ink cartridges, batteries, health and beauty markets are not regulated, so manufacturers and their brand image could benefit from adding identification to help ensure product quality along with revenue protection.

Protecting Appliances and Industrial Equipment

Some home appliances, such as food preparation mixers and processors, as well as beauty products like curling tongs and face care, have attachments that may even change the function of the appliance. A single-wire memory device can provide the proper identification and other desired information to the appliance to avoid improper use, equipment damage and even injury to the user.

Industrial equipment itself can be quite expensive but the power cable and connectors they require to handle high power are expensive items as well. Single-wire memory can provide the proper identification and avoid damage and expensive repairs to both the equipment and the attaching cables.

In addition to handling power, industrial and commercial applications require expensive cables to handle data. For example, with fiber optics, the cable needs the capability to self-identify and provide information including length and other optic parameters, connection history, serial number and manufacturing details to the network. In addition to this information, the cable can also contain tracking codes that make counterfeiting more difficult. A single-wire memory device can provide all this information.

For more expensive consumer and commercial products, it is not uncommon for several aftermarket suppliers to offer low-cost charger/power supply units as replacements. Unfortunately, an improperly matched or poorly designed charger can cause failures in the equipment. The solution to the problem could be to integrate a single-wire memory device inside the charger plug for identification. If the connected equipment cannot read the ID chip in the charger plug, it will not charge and is protected from potential damage.

Figure 3. Adding connector identification using Single-Wire Memory (AT21CSx1)

The ID in some cables is recognized by the medical equipment to verify that the cable, especially a power cable that identifies the voltage, current carrying capability and other factors, is acceptable for the device. All this information can be stored in single-wire memory.

In summary this article describes the need to add memory to add-on devices and peripherals. Part 2 will show how single-wire memory can be easily implemented for applications that require a small amount of memory, need to address basic security, and not consume a lot of space.

Further information on the single-wire products are available on the Microchip website.

Click here to read the next article which describes the technicality of adding the single-wire memory to a product.