In this two part blog series we will discuss the promise of embedded barcode reader options,
considerations for successful implementation, and the latest trends with embedded scanners. We will start off by talking about what an embedded barcode reader does and how the type of data needed to collect will determine the type of scanner needed and what aspects of engineering must work harmoniously for successful implementation.
Barcodes and the readers designed to decode them are a well-known, structured system of data collection. They are based on the idea of turning a printed pattern of information into a usable piece of data, and are widely used by most businesses in every corner of the globe.
Embedded barcode readers, as the name implies, are readers that are embedded within machines and kiosks. Unlike hand-held readers which are moved by hand to the barcode, embedded readers are typically in a fixed position and the barcode or object with a barcode on it, is moved to the reader. In the case of kiosks the object is typically presented by a person. For machines the barcoded object is typically automatically conveyed past the reader.
Embedded barcode readers combine mechanical components, electrical components, and software. These three aspects of engineering must operate properly and cooperate harmoniously in order to achieve a reliable and efficient reader. Successfully introducing embedded readers in a host application involves the indispensable stages of design and prototyping. The design stage of any embedded reader project is very important because it answers the most critical questions regarding its overall operation:
- What kind of data needs to be read?
- What kind of label is required?
- How much data needs to be read?
The amount of data ultimately determines whether a 1D (1-dimensional) or 2D (2-dimensional) barcode reader will be used. 2D labels contain more data than 1D labels and are therefore the route of choice for more complex applications. Let’s break down the difference between the two:
1D Embedded Readers
1D barcodes is the older of the two technologies. There are two types of 1D readers:
1D laser readers. These can read large size labels from a long distance in a wide variety of lighting conditions. Because of the potential for damage if a laser has the potential to come in contact with someone’s eye, there can be labeling and reporting requirements when using a laser based scanner. This reporting requirement varies based on the strength of the laser.
1D CCD readers. These are very reliable and do not have the same use limitations as do laser readers as far as reporting. However, they have more limitations in the reading distance and the label sizes.
2D Embedded Readers
While barcode scanning technology has existed for more than 30 years, 2D barcodes have only found wide use in recent years. 2D readers are essentially digital cameras but with software that has the ability to “see” and decode the image. 2D readers are available in two basic configurations:
2D scan engines. These readers consist of a scanning head and a separate decoder board. The board and the scanning head need to be in close proximity and any project using this configuration must take into account the communication bus between the two.
6-Position 2D readers. These are single assembly readers that contain both the scanning head and the decoder board. For this reason, 6-position readers are regarded as off-the-shelf components.
Considerations for Successful Scanning Implementations
Every barcode scanning project has to take into account mechanical, electrical and optical aspects. The following are some important design elements to consider:
- Scanning distance and mounting. Every reader type has a maximum scanning distance that has to be respected. This holds for both stationary and hand-held/portable applications.
- Scanning angle. Despite the popular belief that readers have to be positioned perpendicular to the barcode surface, such an orientation will lead to an effect called “specular reflection”. In effect, the direct reflection from the laser (in the case of a laser reader) or light source (in the case of a CCD reader) can blind the reader. Therefore, the embedded reader should be mounted with a small angle from the perpendicular up to a maximum of about 13o.
- Power supply constraints. Providing continuous and uninterrupted power to the reader is essential and must be ensured even for portable and hand-held applications.
- Data interface. The two main data interface options are USB and RS232. USB is newer, faster and now more widespread in use than RS232, so it represents a more future-proof choice. RS232 may be the protocol of choice with older legacy equipment that offers no alternative connectivity options.
- Extra features. Integrating extra reader features increases system complexity but adds more value for customers. The sensors of 2D readers are ideal machine vision tools, while the lasers of 1D readers can perform tasks like distance measuring or liquid level sensing.
To conclude part 1 of this 2-part blog series, there are many things to consider when designing in an embedded barcode reader. Look for part 2 of this blog coming out next month where we discuss the latest trends with embedded scanners and the consequences of a bad reader choice.
About the Author
Charles Fisher is Director of Sales of RESCO Electronics, a manufacturer of electronic assemblies
and a value added reseller of auto ID equipment . Charles is a seasoned International Sales and Sales management professional with over 20 years in the electronics industry with extensive experience with Auto ID and data collection solutions, wire harness and electro-mechanical manufacturing, and supply chain solutions. During his career Charles has held positions with Milgray Electronics, Bell Industries, All American Semiconductor and Reptron Electronics.
Charles is a graduate of the William Penn Charter School and Saint Joseph’s University with a degree in International Relations. He currently resides in Maryland with his wife and 2 daughters.