DIY pc-interface for Cressi Archimede I/II / Apex Quantum / Tusa IQ-700 / Nitek Duo

[dexter98]

Great! Thank you very much for the pictures! This is VERY usefull information!!!

As I already expected, it is a standard USB-to-serial interface with only very few extra parts. The PCB shouldn't be too difficult to reverse-engineer, since there are only very few traces on the bottom of the PCB.

The only real problem is U4. It is an EEPROM (a little bit like flash memory), which tells the interface itself (the PL-2303X) to use a custom VID/PID. I know there is a very simple software tool available to program the EEPROM without ANY modifications to this hardware, but it is only available to manufacturers. If anyone has access to this tool, it would be VERY helpfull!

If other dive-computers ARE going to work with the Cressi-sub software, the final interface will be even much more simple and can be constructed from only a few parts and should be connected to a serial port on your PC or a standard serial-to-USB interface.

 

[dexter98]

FIRST DRAFT VERSION SCHEMATIC AVAILABLE!!!

IMPORTANT NOTICE:
THIS SCHEMATIC IS NOT TESTED AT ALL YET. DO NOT BUILD THIS SCHEMATIC. TESTED VERSIONS WILL BE POSTED IN THE NEAR FUTURE.


From the pictures from Bill, I have managed to make a very simple schematic for a PC-interface on the serial port. This interface is only going to work if the software from Cressi-sub also accepts (seiko) divecomputers from other manufacturers. But if that's the case, we're done!


The principe is quite simple:

- T1 inverts the data from the PC (available on pin 3 of the PC-connector) and puts it on the data-line of the dive computer. D5 protects T1 from the negative output of the PC and R3 limits the current, since the signal comming from the PC is symmetric (+9/-9).

- T2, T3 and T4 invert and amplify the signal from the divecomputer (0/+3.3) to a symmetric PC-signal (+9/-9). R7 pulls the signal down to -9 if T4 is not conducting.

- R1 acts as a pull-up resistor to keep the dataline to the divecomputer high if no data is transfered. D1 and R2 limit the input voltage to this resistor.

- D2, D3, C1 and C2 act as a rectifier to generate a positive (+9) and a negative (-9) supply voltage.

- For correct handshaking, pins 1, 4 and 6 and pins 7 and 8 are connected on the PC-connector.

As stated before: I have not tested this schematic at all yet. I will do this when I can borrow the divecomputer from a friend of me, which will be in a few weeks.

 

[PRIMO_STADIO]

Your Work Is Great!!!!!

 

[dexter98]

Thanks

Please follow this thread for the last information:
http://www.scubaboard.com/showthread...=137293&page=3

 

[PRIMO_STADIO]

Sorry, but the link you posted doesn't work...

 

[dexter98]

Hmmm, ok, I see! Direct copying does not work on this forum :s

Hereby the updated link:
http://www.scubaboard.com/showthread.php?t=137293&page=3

 

[ultravinnie]

simple design using an old rs232 level shifter. ds14c86.

should be fairly easy to hack unsing a max3232 and osme other small parts.

the USB thinge dexter is working on is a bit harder ( i know dexter form an electroncs forum ) the problem is the data store din the on board eeprom.

anyway.

 

[dexter98]

simple design using an old rs232 level shifter. ds14c86.

should be fairly easy to hack unsing a max3232 and osme other small parts.

the USB thinge dexter is working on is a bit harder ( i know dexter form an electroncs forum ) the problem is the data store din the on board eeprom.

anyway.

Hehe. Nice to see you here too Small world afterall...

The reason why I chose to build a dicrete level shifter is that the max232 consumes some power, which is quite limited on the serial port. And I needed an open-collector output anyway, which means that I have to invert the data twice if I'm going to use such the max232 level-shifter.

The data in the EEPROM is no problem anymore I have found a datasheet from Moschip, which builds an exact copy of the chip and supplies the exact layout of the EEPROM data.

The documentation is as good as ready. The last step is to etch the PCB and test if it is working correctly. I'll hope to do that tomorrow and present you the final results at the end of this week!!!

 

[dexter98]

OK, FINAL (WORKING) VERSION AVAILABLE FOR DOWNLOAD!

Please see the following thread for more information:

http://www.scubaboard.com/showthread.php?p=1806921#post1806921

 

[blibecap]

Wow you guys are doing great. Let me share my idea about the mechanical connection. First of all you need to reverse the DC+ and DC- connections (swap there locations DC+ becomes DC-). Drill a small hole in each pad and epoxy a small hollow stand off over the hole on the component side. Get a small screw and nut the will slide threw the standoff and it needs to be about 1/2 inch longer. Get a small spring (from the inside of a ball point pen). Put the spring on the screw, insert it threw the board PC side and the standoff and put the nut on. Now that the connections are reversed you place the interface across the face of the computer and make the connections. Once the interface is enclosed in a box you can use a rubber band or Velcro to keep the tension on the springs and the connection to the interface. It might also be a good idea to add a spring or two to the other side of the box to provide tension to the other side of the computer. I hope you get the picture if not I may be able to draw up something. If you have any questions drop me a note. Mr_Bill@mailcity.com