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ROJ and Mares: Creating a Function-Rich, Wrist-Based Diving Computer with Maxim Analog and Power Management ICs

ROJ, based in Biella, Italy, is an electronics designer, developer, and manufacturer that produces solutions for a wide range of applications, including textile manufacturing, electronic production, bank automation, sports equipment, construction, logistics, and farming. One of its clients is Mares, the Rapallo, Italy, developer of innovative dive technologies, founded in 1949 by Ludovico Mares. Together, they’ve produced Mares’s flagship product, the Genius wrist dive computer. The Genius computer is unique for its ability to deliver an array of functions in a compact, low-power format. Equipped with a full-color, high-resolution display, the computer provides predictive, multi-gas functions; depth display up to 150m; a logbook with multiple graphs; map viewing; timekeeping; a decompression dive planner; a fulltilt digital compass with bearing memory and stopwatch for underwater navigation procedures; and much more. Its “brain” is powered by the ZH-L16C algorithm (the classic Bühlmann decompression algorithm) and features an editable gradient factor that can be selected based on the user’s physical and physiological condition on a given day.

Challenges

  • Create compact, wrist-worn diving computer with rich functions, long battery life, and high performance
  • Meet aggressive time-to-market schedule

Solutions

Benefits

  • Met stringent power, performance, noise immunity, and size requirements
  • Saved a year in design cycle
  • Lowered BOM as highly integrated ICs reduced need for discrete components

Mares’s flagship product, the Genius wrist dive computer, provides an array of rich functions in a compact, low-power wearable.

Challenges

Vittorio Loggia, an electronics designer and product manager, worked on the ROJ team’s Digitronic area to develop the Genius computer. According to Loggia, there aren’t any dive computers like the Genius on the market in terms of its many functions and battery life—its rechargeable battery lasts for 40 hours of dive time on a full charge. Designing such a unique device came with many challenges, he noted. To provide a value-added experience for end users, the computer had to be small enough to be wristworn while also highly integrated with a large memory, low power consumption, long battery life, and long-range underwater communications. Delivering underwater communication proved to be a tough task due to noise sensitivity. As a result, the engineering team knew it was important to reduce noise on the power supply and the analog signal. The underlying ICs in the Genius computer had to meet strict size, power, and performance requirements.

Solution and Benefits

The ROJ team has a long history of collaboration with Maxim, so Maxim components were their first choice. Team ROJ recognized that, given their aggressive time-to-market targets, they needed to be able to rely on the ICs to perform as specified. Loggia recalled losing one year’s time on a past project because the part (from another vendor) had some problems. However, before making their final decision, Loggia and Mares performed a comparison of Maxim’s ICs against other ICs on the market. In each comparison, the Maxim part met the team’s stringent specifications—or, in some cases, there was not an equivalent part available from other vendors.

The Genius computer includes these Maxim ICs:

The MAX4257 op amp was essential in producing a small, low-power radio capable of high-performing, long-range underwater communication. “The MAX4257 is the best component I know on the market, with a very small package, very low noise, high gain, and very low power consumption,” said Loggia. Also used in the radio, the MAX17112 boost converter increases voltage on the antenna from the 8V starting point to enable 300V peak-to-peak transmission.

vittorio

“The MAX4257 is the best component I know on the market, with a very small package, very low noise, high gain, and very low power consumption.”

- Vittorio Loggia, Electronic Designer and Product Manager, ROJ