Small form-factor, low-cost computers like the Raspberry Pi are becoming an attractive alternative to more traditional embedded computers in commercial and industrial applications. The availability of versatile cases and other accessories that turn these board-level computers into neat, self-contained and secure system solutions is part of the appeal that is allowing this demand to take off.
The Raspberry Pi was originally conceived as an education computer that was intended to enable people of all ages to learn how computers work and to how to program them. Designed to be capable of performing the same tasks you would expect from a desktop computer, such as running open office applications, playing games and browsing the Internet, the Raspberry Pi has proved to be a popular computing platform not just for hobbyist and educational users, but increasingly in the emerging maker market and now, as we will see here, for commercial and industrial applications.
Cost is the main reason commercial companies are now choosing to use the Raspberry Pi. Previously they would have needed to use single-board computers costing upwards of a hundred pounds and before that, custom designs in the order of £1000. Likely as not, these would have been prohibitively expensive for the types of application where the Raspberry Pi is now finding a home.
However cost isn’t everything and, while a price tag of around £30 may be appealing, these companies need the ability to create a complete solution to their particular problem. This requires more that just a credit-card size computer board – they need the ability to customise their design, to package it up to suit the environment it will be used in with a robust and secure case, and to equip it with the necessary interface and connectivity features. Often, for less tech-savvy companies, this requires the support of a specialist supplier who can, not only supply and advise on all these accessories, but who can also offer additional services to help its customers realise their ambitions.
Companies that lease amusement equipment – fruit machines, pool tables and other coin-operated gambling/slot machines – to pubs and clubs typically rely on staff in those venues to keep an eye on them and report a problem. Other than this, the only feedback the company gets on the status of a machine is when an engineer visits to conduct a routine service or fix a fault.
Unfortunately not every location where a machine is installed has staff that are particularly vigilant so a fault could go unreported for days. One leisure and amusement company decided this wasn’t acceptable and wanted to be able to monitor the status of their machines remotely and get feedback of operating data on a day-to-day basis. The solution to this requirement is a unit developed around the Raspberry Pi that is placed within the amusement equipment. This “black box”, although in reality it could be one of many colours, is able to capture information from the host machine and communicate this data either immediately or on demand back to a monitoring centre over WiFi and/or 3G networks.
In specifying this monitoring unit, it was realised that because the company has little control over the machine’s local environment, it would be prudent to provide a back-up battery within the unit to sustain it during a power outage. They also wanted to protect the machine from unauthorised access and send an alert in real-time if anyone other than an engineer opened the machine. And naturally all of this functionality requires the entire unit to be compact enough to be mounted within the host machine without interfering with its other mechanical and electrical systems.
This requirement was met with a design that placed the Raspberry Pi in a case that was large enough to accommodate a lithium-polymer back-up battery together with an additional custom PCB that both provides a fixing point for the battery and contains the battery control circuitry as well as the logic-level conversion and serial interface devices to communicate with the machine itself. The case, shown open in figure 1, also contains an RFID transceiver board, with printed antenna, that detects the RFID tag worn by an authorised service engineer to avoid triggering the anti-tamper alarm.
Figure 1. Gaming machine remote monitoring unit showing the Raspberry Pi in its case together with the additional boards and battery that are accommodated by the spacer that raises the overall case height
Another feature of the case used for this design (not evident in figure 1) is the provision of a cover for the SD card slot that provides further security against tampering. Figure 2 shows the fully assembled case and the custom-designed cable used to connect this monitoring unit with the host machine.
Figure 2. Fully assembled remote monitoring unit with cable for connection to host machine
Point of Sale (POS) systems have been deployed at the counters of fast-food restaurants to simplify the ordering of meals for many years. In more recent years handheld terminals have extended this capability to orders taken at the table of more traditional restaurants. Restaurants that provide a takeaway or delivery service can also benefit from the same systems to process orders placed online or over the telephone.
One downside of telephone ordering is that in addition to entering the food requirements, the person taking the order has to obtain the customer’s details i.e. name and delivery address. One company, that provides a restaurant POS and delivery management system, realised they might be able to recognise regular customers from their telephones’ caller ID and use this information to streamline and speed up the ordering process.
This requirement has been translated to another unit, designed around a Raspberry Pi combined with a USB-powered modem, that sits between the client’s phone network and existing hardware. This unit has to be discrete and secure enough to be placed in the client’s business premises and the implementation has to ensure no disruption to their legacy network connection.
For this particular hardware design, the Raspberry Pi board was modified (by the case supplier) to remove a pair of USB ports to make space to accommodate the modem card that is mounted within the case and connected with a custom-designed cable. Once again security is reinforced by the use of a cover for the SD card, preventing access the system’s customised program code. Additionally each unit has its line connection tested and is then identified for record-keeping purposes with a sticker that displays a unique serial number and barcode. Figure 3 shows the final unit while the open-case photo in figure 3 shows the modification required to mount the modem card.
Figure 3. Caller identification modem unit used for restaurant POS system
Figure 4. Internal view of caller ID unit showing modification of Raspberry Pi board and case to accommodate a telephone modem
The versatility of the Raspberry Pi is certainly underlined by the extent to which it can be applied to a wide variety of applications. Making these a practical reality though requires an equally diverse range of interfaces and the means to package all these into functional units. System developers often bridge the gap between the suppliers of the Pi boards and all their accessories and the end-users who simply require a solution that does what they want and is fit for purpose.
An example of one such solution is the unit shown in figure 5, where an LCD touchscreen has been mounted on a case that has been adapted to provide screw fixing holes and a cutout to accommodate the screen and allow connection to the Raspberry Pi using a custom cable. And, as we’ve seen with the previous two examples, the application’s program code, which is written around the Pi’s kernel operating system but specifically provides for calibration of the touchscreen, is embedded in the SD card whose access slot is protected by a security cover.
Figure 5. This touchscreen application demonstrates the versatility of the Raspberry Pi
The appeal of the Raspberry Pi is manyfold. For hobbyists and similar geeks, it may be a fun piece of kit that satisfies their enquiring minds – and educationalists are certainly keen to encourage such interest. However more and more people are recognising that the Raspberry Pi board offers a low-cost entry point to a myriad of embedded computing applications that could not justify the investment cost or complexity of developing a ground-up solution using a microcontroller chip. The ability to add simple user interfaces and easily program the Pi to perform dedicated tasks opens up a range of uses that extends into the spheres of industry and commerce.
What we’ve seen in the diverse examples above though is that there is more to such designs than this. The Pi board and various add-on devices are, by themselves, quite vulnerable. Industrial users demand robust packaging to ensure reliable and secure operation and the ability to meet their specific requirements – here one size does not fit all!
Which is where a company like Cyntech Components steps in. Not only does Cyntech provide a wide range of cases in many colours, and electrical and mechanical accessories but it also offers the ability to customise designs to meet whatever quirky need a customer might have. In addition, its applications’ staff are well-versed in solving customer problems and are keen to help you realise your Pi dream.