An Electronic Trigger Unit (ETU) is a little computer that controls the electronics in an AEG or an electronic airsoft gun.
Many people call ETUs a MOSFET interchangeably. Click here to read about MOSFETS!
What Does an ETU Do?
An ETU as defined above is a tiny little computer. These don’t run Windows or Mac, so you cannot check your social media with them. Instead, these little computers are programmed specifically to work inside of an airsoft gun.
An ETU controls the electronics & reads the mechanics of your gearbox to deliver a high-quality experience when shooting. The ETU will read the gears and determine where the piston is. This is important to make sure that semi-auto fire only shoots one bb instead of pulling the piston back multiple times.
The ETU can also read how much the trigger has been pulled.
What is that good for?
When an ETU knows exactly where the piston is, you can do cool things. ETUs are often programmable.
Guns like the M4 only go safe, semi & auto. Using the ETU, we can choose to change Full Auto to be a burst function instead if we want to. This wouldn’t limit us to 3 shot burst. If we wanted to mimic the Vector, we can set full auto to do a 2 shot burst. The ETU will know where the piston is & can count how many times it went forward.
Here’s a quick list of other cool things an ETU can do:
- Pull the piston back 90% of the way for faster trigger response
- Adjust the trigger pull for a hair trigger or a long trigger pull
- Set 2 stages of trigger pulls. Half-pull to be one fire mode & full-pull for a second fire mode
- Change the firemode of safe so you get an extra mode
- Remember stats like how many shots you made with the gun
- Adjust the speed of full auto so your ROF isn’t determined by your battery’s Voltage so you can stay within field limits or save on ammo.
How do I get one?
The best way is to just get a gun like the Novritsch SSR15 with it already installed & tuned properly.
You can hire techs at airsoft shops to upgrade your gun, but once you start upgrading, the time & money between parts & labour costs or your spare time may not be worth it. It’s highly recommended to simply get a better gun & sell your old one to fund your upgrade.