Gate Electronics MERF 3.2v Advanced MOSFET

[aznriptide859]

Gate Electronics MERF 3.2v Advanced MOSFET Review

by aznriptide859

 

I didn't see any articles regarding this FET, so I figure I post this for discussion and to show everyone this FET. I'll update this first post as I get through more functions.

 

Long story short, there was a game on 2/18 I was preparing for (which eventually got canceled....lol), and I rushed to get a FET so I could use my 11.1v lipos for my Thompson without killing any more trigger contacts. Although I'm a huge AWS proponent, Frank hasn't made non-Raptor/Stealth FET's in a long time, and I was a bit indecisive to get an Extreme-Fire one, especially since I didn't know how fast it would get to me.

 

I recalled a friend finding something called a GateE MERF FET while he was looking for SPEED Adjustable Triggers, which seemed extremely intriguing. My local store in Houston had a few units, and their most advanced Burst unit only cost $60 (here: http://www.tx911gear.com/GATE-MERF3-2-MERF-3-2-ADVANCED-MOSFET-UNIT-W-3RD-p/gate_merf3.2.htm, or on WGC here: http://www.wgcshop.com/wgc2008/main/product_detail1.php?search_From=searchItem&item=GATE-MERF32&search=special&rs=mosfet&catid=&cat=) for a FET that almost has the same functions as an AWS Sentry/Pulse or an EF Cheetah/Jaguar (sorry someone correct me on this, since I don't know much about EF's FET's). I went ahead and bought a unit today.

 

From what I can tell, Gate Electronics is a Polish company making these FET's. The item site info is here: http://gatee.eu/index.php?option=com_content&view=article&id=74&Itemid=72&lang=en

 

 

Their boxing is very nice.

 

Stealing from their page, the main functions of this FET are:

1. MOSFET

2. Active Brake

3. Protections for Li-Poly/Li-Ion/LiFePO4/NiCd batteries

4. Short-circuit protection

5. Over temperature protection

6. Programming

7. Rate Of Fire Control

8. 3-rd burst mode

9. Smart Trigger

10. Operating modes:

- Simple mode. No modification to your AEG is required.

- Enhanced mode. Trigger connected to system.

 

One of the key selling points to me is the ability to switch the FET between guns then reprogram it accordingly. The FET has two settings - simple (similar to the Burst or Avocado FET) where it simply protects the trigger contacts from arcing and a simple safe-semi-burst function. However, if you wire the FET directly to the trigger contacts, you get more functions (AB, Lipo protection, etc.); however because the contacts can be wired with an included plug, you can simply unplug the FET and use it on other guns with the same wiring setup.

 

 

The contents are sponge padded, and come with:

 

1 x MOSFET Unit

1 x Programming Button

1 x Direct Trigger Contact Wiring

1 x Alternative Trigger Contact Wiring

2 x Deans Connectors

4 x Heat Shrink (for the Deans connectors)

 

No manual is included, however one can be easily found on GateE's website (www.gatee.eu).

 

 

The box offers two types of wiring - one where you directly wire the contacts to the FET (similar to Cheetah and Lion FET's), or where you reroute and merge/split the trigger and motor wiring (similar to older AWS Pulse FET's). At time of writing I will be doing the direct soldering method; both methods are explained in the manual. Note that this engages "enhanced mode", where all the features are available, as opposed to Simple Mode which only offers trigger protection and a simple burst function. I believe the trigger wiring is routed to a JST plug.

 

There is also a "programming button" for Simple Mode use - the gun will not shoot unless you program it. Using the button is easy - short presses are "next", and longer presses are "enter" or "save". In Enhanced Mode, trigger pulls are used instead of the button.

 

 

 

The FET unit is very nice - it's a little bulky, but should fit in most setups very well. The outer is heatshrinked with clear heat shrink. At one end is the male Deans to the battery, and the other end contains the programming/trigger male plug, as well as the female Deans to the motor.

 

 

Here it is attached to my Thompson in Simple Mode. Note that in simple mode, trigger arcing is not 100% eliminated, as there will still be some arcing when the trigger is released (thanks Maekl and Anachro12 of ASM).

 

Now, here's the best part of the FET - the programming. Everyone knows both EF and AWS FET's all use the "motor buzz" method of feedback to know which settings are programmed. However, GateE has decided to use lights.

 

 

To be honest I've never used either EF or AWS advanced FET's, but comparing to what I've heard about them, this is by far the easiest to program. Yes yes I know I can't program it mid-game or mid-field without a manual, but seeing lights and KNOWING what program has been selected is much better than just following motor buzzes. Each setting has a different light setting - the green lights signify which feature you're adjusting (ROF rate, battery selection, burst, etc.), and the orange lights signify which setting within the feature you select. There are color codes in the manual to tell you what each combo of lights means - so simple, and as a lazy tech chairsofter I just LOVE it.

 

One other benefit is you can program the FET with it just plugged to the battery and using the button - great way to change programming while switching between guns!

 

 

As a reference, Gate's manual does not say what each of the colors mean, but it's pretty simple:

 

Full square - solid light

Triangle - flashing light

Triangle, same direction - two lights flashing at same rate

Triangle, opposite direction - two lights flashing at opposing rates

 

After firing the gun on Simple Mode, I can easily tell my battery (11.1v 1600mah 25C) is way overpowered for a stock TM gearbox - semi gives me 2 round burst 80% of the time. Active Braking is not turned on in Simple Mode, so to be able to observe all the functions, I will have to solder the trigger wiring directly to the FET. The manual doesn't say which direction the trigger wiring should be soldered, but I believe it doesn't matter.

 

 

The wiring coming from the trigger harness. Because the wiring is so thin there shouldn't be a problem routing it through the gun along with the motor wiring.

 

 

Now, testing the sucker. I did two videos...and I'll admit I sound like a retard on camera.

 

First video shows the normal safe-semi-auto operation, as well as the ROF adjustment feature.

 

 

Second video shows both safe-semi-burst and safe-burst-auto operation, as well as burst timing adjustment.

 

 

You'll notice that you have to unplug the battery and motor leads every time you want to change programming (at least that's what I've been doing, I assume you can't just unplug the motor wiring while the battery's plugged in). A bit annoying to be honest, so when soldering wires leave yourself some space so you can pull out the plugs and access the FET better (if you can't tell, I didn't exactly do that lol, so my FET is pretty much stuck in my stock).

 

The Burst function is great - you basically have full control over the timing of the burst (anywhere from 96ms to 472ms), and it can be adjusted for a wide variety of guns/setups/builds. There are instructions in the manual on how to configure your time to a perfect 3 round burst, but of course you can adjust the burst number to anything from 2-7 or 8 rounds depending on how you like to play. I believe the ROF of the burst still is maintained based on what ROF setting you had it on (mine are probably at 70%), so maximum ROF of a burst is still the maximum ROF of your gun.

 

Firing the gun, the FET does not heat up at all - thank goodness, I've encountered too many smoking FET's in my past. My motor however does heat up under continuous fire (obviously), but that might be due to the battery not the FET. I have not encountered over/under battery protection features yet, but I'm assuming the FET will shut off once the battery reaches below a certain voltage per cell.

 

Overall, I'm very satisfied with my purchase. The MERF FET is easy to install, easy to program, and fits a wide range of airsoft guns as well as multiple types of builds. Perhaps I'm a stupid simpleton, but some things (like my FET's) I want them simplified. It may not be as advanced as some of the super-high-end EF or AWS MOSFET's, but in it's price range the Gate MERF 3.2v gives a great bang for the buck.

 

So in conclusion:

 

Pros:

+Cheap unit compared to other advanced FET's

+Small sturdy construction

+Lots of small extras

+Ridiculously easy programming with light confirmation

+Removable and adaptable to multiple guns

 

Cons:

-Missing features found on other FET's (pre-cocking, AB on/off)

-Basically REQUIRES resoldering contacts if you want all the features

-Trigger arcing in simple mode is not 100% eliminated

-Unplugging the battery and motor wires each time to program is a little annoying

 

I'll update this post and post more pictures when possible, but if anyone else has questions or comments, go ahead and ask.

 

Thanks for reading!

Edited February 23, 2012 by aznriptide859

[intinerious]

Thanks for the review!

 

I was considering these as well but I didn't see much talk on ASM about it in the advance/sniper/standard subforums (those are the ones I generally take a peek at every day).

 

Might consider these for future non-v2 AEGs myself if I needed one quickly since I can grab these from WGC.

 

Oh I think your motor heating up is because of the AB? You didn't mention it in your review there and AB generally heats up the motor very quickly from what I can tell with my old, fried ASCU unit. I disable the AB on my Raptor FETs since I don't really need it and all my guns are in pieces at this time so I can't confirm it for you.

[aznriptide859]

That's what I figured, but too bad you don't have the option of shutting off AB manually.

[intinerious]

That's what I figured, but too bad you don't have the option of shutting off AB manually.

 

Do you run a torque or speed motor? Given the speed motor already heats up quicker than the torque I'd think shoving a torque motor into the gun with AB activated would be better for reducing the maximum temperature change in the motor when the gun is used.

[crackisbad]

you said the motor heats up under continuous fire, does that mean a bunch of semi auto shots or a long full auto burst? Since you guys are talking about AB, I am assuming it is a bunch of semi-auto shots, yes? In that case, same question as above

 

 

Overall, great review though. I love the fact they decided to go with the lights, that looks like a much more intuitive way and easier way to program. At this price I might have to pick one up.

[aznriptide859]

I fire a mix of both (at least dry firing), but I'm only using a stock EG700, no HS or HT motors (although I do believe EG700's are geared towards speed, while EG1000's are geared towards torque). I do have a free SHS HT motor I'm not using, could try to fire it with that?

[intinerious]

I fire a mix of both (at least dry firing), but I'm only using a stock EG700, no HS or HT motors (although I do believe EG700's are geared towards speed, while EG1000's are geared towards torque). I do have a free SHS HT motor I'm not using, could try to fire it with that?

 

Well you'll needa reshim the gun so it's up to you! XD But the SHS HT should in theory produce less heat (with clean comms of course) What spring you're pulling with the gearbox? Keep in mind that you might get pre-engagement with weak springs. The more you activate AB the more the motor should heat up.

 

Oh yeah if you can make sure you don't get pre-engagement the HT should also give you a better trigger response in this case. And I'm not sure if others will agree with me but as far as I can tell most setups are around +1.2J for high speed setups and I really don't see any reason why AB is needed anymore; it only solves double/triple shooting issues and keep your trigger response the same every time you pull the trigger but with the amount of what I would say is damage the motor is taking (since it's producing more heat than usual) there really isn't any point in using AB anymore. You're also compressing the same amount of air in theory and also at the same speed so again I don't see why people will use it for 'DMR' builds either.

 

Anyone else can chime in why they use AB? I'm just curious to know why people still use them if they have a choice not to (i.e. like the Raptor with the ability to set AB or not).

 

 

Oh one more thing I forgot to mention aznriptide; the Raptor that I have (x100) uses a very small beeping noise rather than motor movement for indication. That means you can't set the modes when it's loud during a skirmish site's safe zone but if you can hear the beeps it's pretty easy to set the mode you want. The disadvantage with the light method I would say is that you need to be able to SEE the FET to set the modes. Say if I shove this FET into an M4 buffer tube I'd have a pretty hard time setting the modes if I don't have enough wire length to actually pull the FET out of the buffer. So the AWS and GATE's methods have their advantages and disadvantages, but with the way I set my guns up I prefer the AWS method

[aznriptide859]

Everything as per the video is stock TM (AKA, I really should reshim lol). But yes I can see the benefits and disadvantages of a visual confirmation mode-only method as well.

[Wingmann]

Excellent review and videos, thanks!