Suunto PC Interface

Description: This page contains GIF images of the circuit diagram for the Solution interface, the PCB artwork, the board layout, a typical side elevation of the assembly, a parts list, some hints, and a brief overview of troubleshooting. This is a self-extracting 2.5MB file; although Solution variants are not listed, the same software is used for all older computer types (just use the Vyper version!). Logbook data created with the old "DiveLog" software can be imported into it. The pin numbers for the serial port are for a 9-pin "D" connector, which is usually fitted to COM1 on most PCs. These must not be used with a 25-pin connector; refer to your PC's handbook for the functionally equivalent pin numbers. Alternatively, 9-pin to 25-pin converters are readily available from various suppliers. The PCB image is viewed from the copper side of the board to enable those without access to a laser printer to copy the pattern onto copper-clad board with an etch resist pen. The diameter of the pillars used on the prototype prevented the Suunto from being attached to the interface without first removing the protective plastic screen; by using smaller diameter pillars, it may be possible to leave the cover in position. Ignore the board outline and cut the board to suit the box intended for use. Profiling the sides of the board may be necessary to avoid the PCB guides inside the box. All component holes are 0.8mm, while those for the test pins and pillars should be suitable for the respective parts used. 1.5mm holes were drilled above the cable terminations, allowing individual wires to pass through these for some degree of strain relief for the solder joints. It should be noted that the assembly was built into a second-hand box that did not have a lid; a lid was fabricated from a piece of aluminum. The mechanical fittings (pillars/grommets, etc.) were sourced from a scrap bin. The parts list provided should only serve as a guide to what is needed; the original builder did not acquire the parts from the suggested supplier but mentioned them due to their UK-wide network and public availability. Caution is advised as the transistor and integrated circuit can be damaged by static discharges; proper anti-static precautions should be taken when handling them, and overheating during soldering should be avoided. The DS14C88 is noted as discontinued by the suggested supplier, but alternatives can be sourced from RS Components or CPC. It is essential to use a low-power CMOS device, as the standard DS14888 draws too much power. If the specified PCB stand-offs are unavailable, M4 studding can be used, insulated and fastened through grommets with M4 nuts. The unit can be powered from two PP3 batteries connected via series diodes to prevent shorting out the supplies if the batteries are left off. For those concerned about their PC's COM port levels, a design using a MAX232E is mentioned, which requires a single 5-volt supply and may solve some compatibility issues with laptop computers. However, this may introduce additional problems due to power draw from the signal pins. A USB-to-serial adapter is suggested as a potential solution.

The circuit design focuses on creating a reliable interface between a PC and a Suunto device. The key components include the serial communication interface, which utilizes a 9-pin D-sub connector for standard PC compatibility. The PCB layout is crucial for ensuring proper signal integrity and minimizing noise in the communication lines. The choice of components, particularly the low-power CMOS integrated circuit, is essential to prevent excessive current draw that could lead to overheating and failure.

The PCB artwork is designed to allow for easy replication of the circuit on copper-clad boards, making it accessible for hobbyists and engineers without specialized printing capabilities. The inclusion of strain relief features in the design enhances the durability of the connections, particularly in portable applications where movement and vibration may occur.

The assembly considerations include mechanical stability, with recommendations for using readily available materials to create a robust enclosure. The use of aluminum for the lid and sourcing mechanical fittings from scrap materials demonstrates a practical approach to prototyping, emphasizing cost-effectiveness and resourcefulness.

Static discharge precautions are highlighted to protect sensitive components during assembly, which is a standard best practice in electronics design. The alternative power supply options, including the use of batteries, provide flexibility in deployment scenarios, allowing for portable operation without reliance on external power sources.

Overall, the provided schematic and accompanying documentation aim to facilitate the construction of a functional and reliable interface for data logging applications, bridging older technology with modern computing environments.This page contains GIF images of the circuit diagram for the Solution interface, the PCB artwork, the board layout, a typical side elevation of the assembly, a parts list, some hints and a little about troubleshooting. This is a self-extracting 2. 5MB file; although Solution variants aren`t listed, the same software is used for all the older co mputer types (just use the Vyper version!). Logbook data created with the old "DiveLog" software can be imported into it. The pin numbers for the serial port are for a 9 pin "D" connector as is usually fitted to COM1 on most PCs. They must not be used with a 25 pin connector, refer to your PC`s handbook for the functionally equivalent pin numbers, alternatively 9 pin to 25 pin converters are readily available from RS, Maplin and Tandy.

The pcb image is viewed from the copper side of the board to enable those without access to a laser printer to copy the pattern onto copper-clad board with an etch resist pen. The diameter of the pillars used on the prototype prevented the Suunto being attached to the interface without first removing the protective plastic screen; by using smaller diameter pillars it may be possible to leave the cover in position.

Ignore the board outline and cut the board to suit the box you intend to use. You may need to profile the sides of the board to avoid the pcb guides inside the box. All component holes are 0. 8mm, those for the test pins and pillars should be suitable for whatever parts you use. 1. 5mm holes were drilled "above" the cable terminations, the individual wires were passed through these to provide some degree of strain relief for the solder joints. Please note that I built mine into a second-hand box that didn`t have a lid, I had to fabricate one from a piece of aluminium.

The mechanical fittings (pillars/grommets etc. ) were all "liberated" from the scrap bin at work. The parts list below should only be used as a guide to what`s needed - I didn`t acquire the parts for my prototypes from Maplin but I`ve quoted them as a supplier because they`ve a UK-wide network of shops as well as a website for on-line ordering and they sell to the general public unlike RS and Farnell. Warning, the transistor and the integrated circuit can be damaged by static discharges, never handle them by the leads unless taking proper anti-static precautions and do not allow them to overheat when soldering them into the board (this applies to the diodes also).

* I`ve been told that Maplin have discontinued the DS14C88, until I can check out suitable equivalents etc. this can be got from RS Components, stock no: 633-521 @ £0. 552 (I believe the public can buy at trade counters). Alternatively, it can be got by mail order from, CPC on 01772 654455, their stock no: SCDS14C88N @ £0.

65. Note; It MUST be a low power CMOS device, the standard DS14888 draws too much power from the supplies. If assembling as per the above images, pcb stand-offs of the type used aren`t available from Maplin, however M4 studding (NC25C @ 70p/mtr) suitably sleeved with insulation and fastened through grommets (JX65V @ 47p/10) with M4 nuts should achieve the same purpose.

If desired, you can try powering the unit from two PP3 batteries as shown here. They can be connected via series diodes so that if the batteries are left off, there will be no danger of shorting out the supplies - provided they`re kept away from the PLAN, MODE and COM pins!. For those who may have doubts about their PC`s COM port levels, Reinhard Kopka has a site with a similar design that uses a MAX232E.

This only requires a single 5 volt supply and it may solve some of the problems experienced with laptop computers, however, with this device, all the supply power will be drawn from the positive excursions of the signal pins and this might create extra problems - I haven`t tried it so I can`t say for certain. The solution (no pun intended) is a USB-to-serial adaptor. Whilst I