Thats great, i was looking for such a program but did not know what to call it so i wasn't getting any useful results so thanks a bunch. I am going to re-assemble the circuit and see whether i am as fortunate as you. I also have access to some high quality scopes (at school) but i'm not sure whether i'ld know what to look for... I really wish i knew the protocol that the M2 uses perhaps the port sniffer will help me out a bunch. I'll report back any positive progress.
DIY Mares InfraRed Cable for AirLab/M1/Dacor Darwin -- Works!
- Thread starter PanamaMike
- Start date
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So this is what i'm suposed to see assuming airlab send the same as the M2
IRIS to AirLab: <5180000DA2>
AirLab to IRIS: <5180000DA2><000100001A50000000000D0E0021>
IRIS to AirLab: <512000078F>
from ektm
but this is what i see
<5180000DA2>P?DA<5180000DA2>PS?DA2
etc, etc. I'm not entirely sure the M2 is even reply so much as its recieving a reflection... just a guess because when i remove the computer i get <5180000DA2> with no letters or characters. I did get it to change a few letters here and there by playing with the trimmer but most dissapointing of all i'm not seeing any loading bar action so i'm guessin its not communicating at all...
I don't know what to do from here besides ask some of my elec friends for some insight... lemme know if you make any headway, later.
IRIS to AirLab: <5180000DA2>
AirLab to IRIS: <5180000DA2><000100001A50000000000D0E0021>
IRIS to AirLab: <512000078F>
from ektm
but this is what i see
<5180000DA2>P?DA<5180000DA2>PS?DA2
etc, etc. I'm not entirely sure the M2 is even reply so much as its recieving a reflection... just a guess because when i remove the computer i get <5180000DA2> with no letters or characters. I did get it to change a few letters here and there by playing with the trimmer but most dissapointing of all i'm not seeing any loading bar action so i'm guessin its not communicating at all...
I don't know what to do from here besides ask some of my elec friends for some insight... lemme know if you make any headway, later.
OP
PanamaMike
Registered
I dug out the file CircuitNotes.txt from the file DIYmaresIRcableVer2.zip. Maybe
the information in it will help.
Homemade Serial MARES I.R.I.S. to AirLab Dive Computer Interface Cable
Mike Engelhardt Version 2 01/22/07
This is the second version of my I.R.I.S. serial Interface Cable.
While the first version works fine, I wanted to make an optimized
version with fewer and yet more generic parts. Now I have two
working cables. This 2nd version is simplified from my 1st version.
The transmitter side of this cable is now very simple, powering
itself directly off the Tx pin and using only two generic
transistors, 5 resistors, 3 capacitors, a diode, and an IR
emitter -- instead of a Xtal and some high voltage CMOS devices.
When I did the first version, I didn't know that the baudrate was
9600. I simulated Edward Cardew's receiver design and it looked
marginal for 9600, though it does certainly also work. But I felt
that it would be better if the cable was designed to have smaller
timing errors.
The simulation file, Timing.asc, shows this receiver running side-
by-side with the Edward Cardew design so you can see the improved
timing characteristics with a random bitsteam. The Edward Cardew
design is fine for a square wave, but for random data, it has
pretty large timing errors. Notice that the start bit can be
40% too narrow.
The transmitter works from 0" to 5"(13 cm). The receiver can be
adjusted to work also to this distance, but I've adjusted the
design to only work to 2 cm for improved rejection of ambient
light.
1. The cable was tested with IRIS version 2.2.2 and an AirLab.
2. The baud rate is 9600 baud, 8 bit, no parity, one stopbit,
no hardware handshake, no software handshake. DTR must
be set high. IRIS sets your port to these settings.
3. The IR is 56KHz CW or ASK(Amplitude Shifted Keying). A
multivibrator type oscillator made with 2 cross-coupled 2N3904's
powered directly by the Tx signal works fine and saves procurement
of the high voltage CMOS devices and Xtal.
4. The cable must echo data transmitted from the IRIS software back
to IRIS. The signal echoed back is mostly due to capacitive
coupling between the transmit and receive IR diodes. The original
version of my design had a bipolar signal for Rx because that
is the RS232C spec. I was going to use the Tx pin as a negative
supply, an idea I got from the Mouse Systems serial mouse I
cannibalized for this project, but as this echo occurs during
the Transmit, I just used the comparator to bring Rx to ground
-- a technique one can usually get away with -- because this
negative supply would not be available during this echo.
The photograph Cstray.jpg is an oscillogram of Q4's collector
voltage with the Tx pin is high showing the coupling between
the transmitter and receiver that causes the echo. The simulation
file Cstray.asc shows that 0.2pF can cause this.
5. You can debug the receiver to some extent with a consumer
electronic IR remote control, though these seem to usually run at
a 40KHz instead of 56KHz and at much lower baudrate. This allows
you to at least see if you can detect IR without the transmitter
side runing and capacitively leaking signal into the receiver.
6. If the AirLab receives a command it doesn't understand, it
sends <?3F> to IRIS.
7. IRIS and AirLab transmit data as ASCSII Hex characters enclosed in
angle brackets. Below is how the dialog starts out with an AirLab:
IRIS to AirLab: <5180000DA2>
AirLab to IRIS: <5180000DA2><000100001A50000000000D0E0021>
IRIS to AirLab: <512000078F>
AirLab to IRIS: <512000078F><00000000000000A0>
IRIS to AirLab: <5100013C9D>
AirLab to IRIS: <5100013C9D><07D30701021A001A014D12700
0A0201000000064FFFF0000000000040A3B0
F6E0F6E0F6E0F6E0F6E0F6E0F6E0F6E0F6E0
F6E32640C1A000000000F00C3>
IRIS to AirLab: <513C013CB3>
The file Eavesdrop.txt contains the entire log from downloading
the dummy dive that is in the AirLab as it leaves the factory.
The file is acquired by eavesdropping on the RS232C connection with
another PC. Multiple runs showed that the cable runs shows this
cable makes no bit errors. It takes 1min 20sec to read this file.
BTW, it'd be nice if someone could figure out how to read it, or
at least how the last two character checksum is computed.
8. Its extremely useful to have a terminal program so you can
send <5180000DA2> down the cable and listen for
<5180000DA2><000100001A50000000000D0E0021> to come back to
see when the cable and positioning is correct. Once the
cable is working correctly, it's quite insensitive to position
and aim. The console program CommTest.exe supplied in this
release works great for this.
Regards,
--Mike
the information in it will help.
Homemade Serial MARES I.R.I.S. to AirLab Dive Computer Interface Cable
Mike Engelhardt Version 2 01/22/07
This is the second version of my I.R.I.S. serial Interface Cable.
While the first version works fine, I wanted to make an optimized
version with fewer and yet more generic parts. Now I have two
working cables. This 2nd version is simplified from my 1st version.
The transmitter side of this cable is now very simple, powering
itself directly off the Tx pin and using only two generic
transistors, 5 resistors, 3 capacitors, a diode, and an IR
emitter -- instead of a Xtal and some high voltage CMOS devices.
When I did the first version, I didn't know that the baudrate was
9600. I simulated Edward Cardew's receiver design and it looked
marginal for 9600, though it does certainly also work. But I felt
that it would be better if the cable was designed to have smaller
timing errors.
The simulation file, Timing.asc, shows this receiver running side-
by-side with the Edward Cardew design so you can see the improved
timing characteristics with a random bitsteam. The Edward Cardew
design is fine for a square wave, but for random data, it has
pretty large timing errors. Notice that the start bit can be
40% too narrow.
The transmitter works from 0" to 5"(13 cm). The receiver can be
adjusted to work also to this distance, but I've adjusted the
design to only work to 2 cm for improved rejection of ambient
light.
1. The cable was tested with IRIS version 2.2.2 and an AirLab.
2. The baud rate is 9600 baud, 8 bit, no parity, one stopbit,
no hardware handshake, no software handshake. DTR must
be set high. IRIS sets your port to these settings.
3. The IR is 56KHz CW or ASK(Amplitude Shifted Keying). A
multivibrator type oscillator made with 2 cross-coupled 2N3904's
powered directly by the Tx signal works fine and saves procurement
of the high voltage CMOS devices and Xtal.
4. The cable must echo data transmitted from the IRIS software back
to IRIS. The signal echoed back is mostly due to capacitive
coupling between the transmit and receive IR diodes. The original
version of my design had a bipolar signal for Rx because that
is the RS232C spec. I was going to use the Tx pin as a negative
supply, an idea I got from the Mouse Systems serial mouse I
cannibalized for this project, but as this echo occurs during
the Transmit, I just used the comparator to bring Rx to ground
-- a technique one can usually get away with -- because this
negative supply would not be available during this echo.
The photograph Cstray.jpg is an oscillogram of Q4's collector
voltage with the Tx pin is high showing the coupling between
the transmitter and receiver that causes the echo. The simulation
file Cstray.asc shows that 0.2pF can cause this.
5. You can debug the receiver to some extent with a consumer
electronic IR remote control, though these seem to usually run at
a 40KHz instead of 56KHz and at much lower baudrate. This allows
you to at least see if you can detect IR without the transmitter
side runing and capacitively leaking signal into the receiver.
6. If the AirLab receives a command it doesn't understand, it
sends <?3F> to IRIS.
7. IRIS and AirLab transmit data as ASCSII Hex characters enclosed in
angle brackets. Below is how the dialog starts out with an AirLab:
IRIS to AirLab: <5180000DA2>
AirLab to IRIS: <5180000DA2><000100001A50000000000D0E0021>
IRIS to AirLab: <512000078F>
AirLab to IRIS: <512000078F><00000000000000A0>
IRIS to AirLab: <5100013C9D>
AirLab to IRIS: <5100013C9D><07D30701021A001A014D12700
0A0201000000064FFFF0000000000040A3B0
F6E0F6E0F6E0F6E0F6E0F6E0F6E0F6E0F6E0
F6E32640C1A000000000F00C3>
IRIS to AirLab: <513C013CB3>
The file Eavesdrop.txt contains the entire log from downloading
the dummy dive that is in the AirLab as it leaves the factory.
The file is acquired by eavesdropping on the RS232C connection with
another PC. Multiple runs showed that the cable runs shows this
cable makes no bit errors. It takes 1min 20sec to read this file.
BTW, it'd be nice if someone could figure out how to read it, or
at least how the last two character checksum is computed.
8. Its extremely useful to have a terminal program so you can
send <5180000DA2> down the cable and listen for
<5180000DA2><000100001A50000000000D0E0021> to come back to
see when the cable and positioning is correct. Once the
cable is working correctly, it's quite insensitive to position
and aim. The console program CommTest.exe supplied in this
release works great for this.
Regards,
--Mike
Thanks Mike for the valuable info. It should help us going. I'm waiting for some parts in the mail and for my friend's oscilloscope. If my second attempt to make Edward Cardew's design work fails I'll scrap it and try yours. I've got your zip package earlier, run in simulator, but thought debugging CMOS circuit would be easier that transistors.
Thanks Mike, i'm going to give it a shot. Your comparison in LTSpice is convincing enough for me. I tried to attach you DIYver2.zip to this post hopefully it works because some people do not have yahoo accounts (like myself until now).
Don, I'm about to give up. I tried all schematics, even got couple of TSOP4156 modules, but nothing works. CMOS seems to be working, I can see signals going out using remote from TV. But I can't make it talk to M2. Will try couple of ideas tonight, if it failed, I'll probably buy one online ($90 shipped on Scuba.com). Just can't survive another week with 2-3 hours of sleep every night 
WJA- i have no idea whether this works with the Nemo...
MrSpock- Fair enough, I am still playing with ideas but generally not too late... I actually cracked my electronics texts the other day just to brush up on some basics. I have had recomendations from some friends to NOT use a solderless breadboard for this type of circuit because stray capacitance is inherent in these prototypes. The capacitance can destroy high frequency signals and even though we are dealing with low freq. it generally distorts your square waves throwing timing and logic off. I havn't been able to use a good enough scope to verify this as a problem but i have seen the results in past projects. It is recomended you use proto board and solder it or even do the extremely messy looking method of soldering the components to each other to reduce lead lengths.
Have you been prototyping on a solderless breadboard by any chance? I'm guilty... i'll keep reporting back anyways..
MrSpock- Fair enough, I am still playing with ideas but generally not too late... I actually cracked my electronics texts the other day just to brush up on some basics. I have had recomendations from some friends to NOT use a solderless breadboard for this type of circuit because stray capacitance is inherent in these prototypes. The capacitance can destroy high frequency signals and even though we are dealing with low freq. it generally distorts your square waves throwing timing and logic off. I havn't been able to use a good enough scope to verify this as a problem but i have seen the results in past projects. It is recomended you use proto board and solder it or even do the extremely messy looking method of soldering the components to each other to reduce lead lengths.
Have you been prototyping on a solderless breadboard by any chance? I'm guilty... i'll keep reporting back anyways..
