The COPIS Megalodon

The COPIS (Ko-pes) Megalodon
By Ron Micjan



There has been much speculation and discussion on this topic for some time, but now here is the official product release and description of the COPIS (Constant Oxygen Pressure Injection System) Megalodon CCR.


First a Bit of History

While at my ISC Megalodon build course, I made a bit of a mistake and FOD’d a very expensive acetyl Meg head making it unusable for sale (whoops), Leon didn’t take me out and whip me with marine grade gas impervious cable with the ends frayed, but I felt pretty bad after doing it. As the week progressed I thought of a way to make that head useful and because I cut my teeth on CCR using the KISS system of oxygen injection, I put together a proposal in my head for making a leaky valve system in a MEG head. I sat down with Leon and put the idea on paper, he told me to use what I needed and give it a go. I wanted a spare head to have for expeditions and trips, just in case my primary failed.

So, after many hours of hard thinking, research and work, I came up with a way to make this happen. The key points in my mind were:

• Use as many off the shelf parts as possible
• Keep it simple!
• Keep it recreational (ISC already has an Apecs MEG, capable of 600+fsw)
• Keep the price down and affordable for guys like me who don’t have money spilling out of their pockets
• Make it reliable and robust
• Make sure it’s upgradeable to a full electronic MEG

I put together the very first unit, over a year and a half ago, using a circuit board for the displays designed by Mark Munro of PPO2.com fame. He was a big help in cutting down one of his designs to fit inside the MEG handset. This was an analog circuit that calibrated by turning small potentiometers on the back of the board, there was even a small LED near the pot's to illuminate them for doing a cal in darkness, the only problem was, you had to open the handset to calibrate. We proposed machining a cap in the end of the handset but that would have added machine time and cost. In the history of the MEG, the only handset floods that have ever happened were from end users opening up the handsets, so this violated the reliable and simple rules. I did dive that unit for 6 months and then passed it on to PattiMegDiver when she decided she wanted a MEG to dive and she dived that for almost a year. I just exchanged her electronics for the new digital version last week.


The new digital version requires no opening of the handset, period. The new version has 3-3.5 digit backlit panel meters running off of a small microcontroller that "does the math" and manages power and backlight functions. The displays are arranged vertically in the stock MEG handset and use the same cable, buttons, battery box, and reed switches as the standard MEG Primary handset. Battery life using 5AA batteries is an astounding 3 months continuous use, this means a complete dive trip without ever bothering to turn off your handset. Calibration is a push button affair using any mix you want, air, oxygen or anything in between, as long as you know the exact concentration of O2 in it.


The way the unit calibrates is as follows. Say the number one display is reading .216 in air, to enter cal mode, push both buttons on the handset until the number one (top) display backlight comes on, then the top button will increment the value by .01 per push, and the bottom button will decrement the display by .01 per push. Either button will accelerate the change by a push and hold. To return the errant display to .209, one would push the bottom button 7 times. To access the second display, press both buttons simultaneously until the second display backlight comes on and the first turns off. Proceed as above until all displays are correct. As stated above, you could also do your cal in pure O2, or any other gas with a known oxygen content. ISC recommends calibrating in pure O2 and verifying the cal in air, or vice versa, to provide the diver with a linearity check of the cells.

There are also a pair of wet sensors on this handset, activating the wet sensors will lockout the calibration system, and activate backlight controls. During a dive, (wet sensors active) pressing the top button momentarily will activate the backlights for several seconds, then turn them off. Pressing the top button and holding until all the decimal points flash once, will activate the backlights for the duration of the dive. You can turn them off again with another press and hold. If the backlights will not activate, this is an indicator that the batteries are low in power and should be replaced at your soonest convenience. There is also a low battery indicator on the display and this is a warning that you would want to change the batteries prior to the next dive. Of course, constant use of the backlights will shorten battery life.

The rest of the rebreather is exactly the same as a stock MEG. The counterlungs, ADV, mixed gas bypass, DSV, breathing hoses, plenum, scrubber options, are all the same. The beauty of this is, you have a very robust and proven platform, that is customizable and upgradeable, with excellent flood recovery options and multiple gas sharing paths, but very simple to dive. The only differences are in the head, the oxygen regulator, and the hose between the oxygen regulator and the head. It is possible to switch between a COPIS head and an Apecs head in 5-10 minutes, less if you have an O2 regulator set up for each.

The difference in the O2 regulator is the addition of an ambient pressure blocker, that keeps the intermediate pressure of the regulator fixed, regardless of the ambient pressure. If you are familiar with SCUBA regs, you know that the IP of a normal reg tracks with depth staying approximately 135-150 psi above ambient pressure. With this type of injection system, if one were to use an unmodified regulator, the O2 flow would increase as depth increased, providing too much oxygen to the diver , a steadily increasing PO2, and risking an O2 tox. This system is only functional to about 300fsw, or where the ambient pressure equals the intermediate pressure the O2 reg is set to. This also requires the diver to set the IP (and subsequently the flow rate) to match his or her VO2, or metabolic oxygen use at rest. There is a small orifice in the hose between the O2 reg and the head, that restricts gas flow to about .5-1.5 liters per minute, again depending on what the IP is set for. We had tried a couple different places to put the orifice, including in the head after the elbow and bulkhead fitting, but decided for reliability’s sake to bury it, and a filter, in the feed hose to protect it from sea water. Not having it in the head also reduces the possibility of the fitting leaking and affecting the PO2, now if it leaks, it will be visible (while in the water) and outside the loop. The system does not use a separately plumbed valve, like on the Jetsam rebreathers, just the aforementioned orifice and the stock MEG O2 manual add button on the right counterlung. The orifice and manual add button are both plumbed to the same regulator, so at depth, the manual add button adds less gas per second, the deeper you go. This aids in preventing a spike in PO2 at depth, where it is most critical. It is also easy to move the oxygen add to the left counterlung, if injecting into the inhale CL is a concern to you.

For those not familiar with this type of injection, this is not a setpoint controller, it is a manual add CCR, just with a slower decay system that gives you longer times between manual injection. The diver is completely responsible for the oxygen content of the loop, and the setpoint control is located between the divers ears. The diver should check loop PO2 every 3-5 minutes and continuously during an active ascent. With a properly set up IP/flow rate, a diver might only have to use the manual add 2-3 times during a constant depth dive. Of course, during ascent, monitoring and adding require more attention.

The differences in the head are: only one battery box, and no switch on it, power is applied by plugging in the cable to the box. This reduces cost and build time.


The connector is also a pathway to software upgrade for the microcontroller. The head has no solenoid, but uses the same through head fitting and quick connect as the Apecs. There is only one handset, but three independent cells and displays.

This, of course, will lead to discussions of limited redundancy, but again, this is a recreational unit, not designed for deep maximum deco diving. If the displays fail, end your dive. If you want a unit to dive deeper and do exceptional exposure diving, step up to the Apecs Meg with its dual controllers and two handsets. With that said, there is a HUD in the works, that will use a second battery box and other than the sensors, will be a completely separate and redundant monitoring system. The HUD will use the same blink pattern as current MEG users are used to and have aboard some really neat functionality stuff.

Also on the head will be at least one empty port that can be easily used to feed a dive computer, such as a VR3, or an HS Explorer, data from one of the oxygen cells for real time deco. There is no problem paralleling two monitoring devices on the same cell, but the prudent diver would always make sure when rotating cells, that the middle cell is on the dive computer. The reasoning behind using the middle cell is that it is proven stable, and not the oldest. If one were to replace the oldest cell every 4-5 months, there would always be one new, one in the middle and one old. The middle one is expected to be the most reliable. The computer cable and port will be a factory option on the units ISC builds.

The COPIS MEG is available to order now, with expected delivery in 60-90 days and the unit will be available 3 ways. One, as a ready to dive unit with cylinders, regs, hoses, sensors, BCD, literally ready to dive. Two as a stripped unit, can, loop, and head only, so you can put whatever cylinders BCD etc you desire. Third as a kit, with a few things assembled, such as the handset and sensor carriage that are critical. ISC is working on a build course, in conjunction with the dive course, so the units can be assembled under tutelage, whether at the ISC facility, or on location. Then step right into the end user course and go diving. We will have units at DEMA, as well as OZ-tek, to show. There are currently 6 units being dived regularly, two in Norway, one up in BC, one in Seattle, Patti’s and one in the hands of Scott Torborg, who is the genius behind the current COPIS electronics and the new HUD. Pricing of the unit is to be in the $6,100 range USD.

So, I am proud as punch to see a major idea of mine get off the ground, its amazing how long and how much work it took, but the end result is even better than I had first imagined. Thanks to all who contributed, Leon, for backing the effort, and the whole staff at ISC, especially Scott, and Mark Munro, who helped with the first analog board back when it was just a toy for me, and Patti, my own little crash test cutie, with a PO2 that never wavers.


Ron Micjan
5 August 2006


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