History

The OBP60 V2 multifunction display is now available in a second, updated version. The reason for revising the fully functional first OPB60 lies in a fundamental change to the concept. The original OPB60 was based on expansion modules such as an ESP32, an e-paper display, a GPS module, and environmental sensors. These modules had to be soldered to the baseboard using through-hole pin headers. In total, this amounted to approximately 60 solder points that had to be soldered manually. Some of the modules only have pin headers on one side and require support during soldering. The display also had to be installed beforehand in order to be soldered. For a hobby project with manual assembly, this might be conceptually sound. However, for mass production, the old approach is very time-consuming and expensive, and only feasible with considerable effort. Furthermore, the modules are not available in sufficiently consistent quality, and significant quality variations must be expected. In the past, there were significant problems with defective modules, particularly the GPS and BME280 modules. Each module therefore had to be manually tested before installation. When inquiries were made about manufacturing in China, the modules could not be sourced through major component distributors, making logistics extremely complex. Furthermore, selling the circuit board without the modules would have been pointless, as a functional test of the board would not have been possible.

Additionally, it turned out that some circuit components were malfunctioning. The backup power supply via the GoldCap for the shutdown process was undersized. The amount of energy was insufficient to erase the e-paper display and put it into a defined state during shutdown. This, in turn, caused problems when switching the e-paper display on. The 3.3V power supply for the BME280 module was also insufficient for reliable operation. After some time in operation, the module overheated, failed, and only communicated erratically with the CPU. The extensive firmware also caused a problem with the RAM. In some situations, it was too limited, causing unintended reboots of the OBP60. There were also occasional problems with the I2C bus when external components were connected. In real-world use, external interference from other components could be fed back into the OBP60 via the I2C bus. Since the same I2C bus also supplies other important components of the OBP60, this had serious consequences for the overall stability of the system. Galvanically isolated bus systems can avoid such problems. With the GPS module used, it turned out that the module’s firmware contained errors. In very specific situations with poor GPS reception, the module sent garbled NMEA0183 telegrams, which nevertheless contained correct checksums. In such situations, the OBP60 could freeze completely because the parser could not handle the faulty data. The OBP60’s firmware has since been updated, and the error has been fixed.

Understandably, it therefore did not make sense to produce the OBP60 in its old form in larger quantities. As described, this would have caused too many problems, and it would have been impossible to implement logistically and in terms of time.

For these reasons, the circuit board was completely redesigned. The goal was to design the boards so that they could be fully automatically populated with predominantly SMD components and contain very few through-hole components. This allows the board manufacturer to fully automate the assembly process, eliminating the need for subsequent manual soldering. This enables the production of any quantity without additional effort. Only the programming and testing remain manual processes, which can also be outsourced to the manufacturer if the necessary test equipment is provided.

During the redesign, several features that proved unnecessary were omitted. The SeaTalk bus and port expansion were rarely used. Measuring the internal humidity of the BME280 is pointless. At one point, there were significant procurement problems with the Bosch sensor, and the price had skyrocketed to an unacceptable level. Therefore, the BME280 was replaced by the BMP280, which measures only air pressure and temperature. It is also much easier to source and considerably cheaper. The GPS module was completely removed; all components related to GPS reception are now mounted directly on the circuit board. High-quality, readily available, and inexpensive GPS chips from China are now used. The I2C, NMEA2000, and NMEA0183 bus systems are galvanically isolated to reduce interference. All three buses are protected against overvoltage, reverse polarity, and overcurrent. There are now also special connectors to which the cable shielding can be attached. These are protected against overvoltages up to 8 kV. An isolating DC/DC converter provides the user with a 5 V supply at 200 mA, which can be used to power external circuits without potential differences. This allows, for example, the simultaneous operation of multiple battery monitors or the easy connection of other sensors.

The supply voltage input is also protected against overvoltage, reverse polarity, and overcurrent. This provides sufficient protection even in the event of a lightning strike. The entire circuit should be implemented in accordance with CE marking requirements. However, this still needs to be verified in a separate test. Galvanic isolation was omitted for the 1-Wire bus, as it is self-powered and requires no external power supply or connection to other electrical circuit components. With appropriate cable shielding, the 1-Wire bus is adequately protected.

The backlight and flash LED are now implemented as RGB LEDs. This allows the light color and brightness to be set separately for each LED.

The e-paper display is directly connected to the mainboard. A carrier plate protects the sensitive glass substrate of the e-paper display. This results in a more compact design, with the board and display forming a single unit. The reduced depth allows the dimensions of the original Raymarine ST60 instruments to be maintained.

Programming the OBP60 is now even easier. The board features a USB-C connector for programming. Thanks to the new ESP32 S3, the USB-to-serial converter is no longer needed, as it’s already integrated into the ESP32 S3. The USB-C port is directly accessible from the back of the OBP60. This port also allows for bidirectional NMEA0183 data transfer, enabling data exchange between devices like a PC or a Raspberry Pi. The OBP60 can also be powered by a USB host, such as a power adapter, that supplies 5.1V at 500mA. The ESP32 S3 now integrated into the OBP60 is currently the most powerful ESP32 available. In addition to larger RAM, the ESP32 S3 also features PSRAM, allowing for a significant increase in available memory.