Eggtimer Rocketry


What is the Eggtimer Remote Switch?

The Eggtimer Remote Switch is a wireless remote control that's used to arm/disarm the electronics in your AV bay.  Unlike traditional switches, it does not require any physical interaction with the rocket to operate; you simply enter the 8-button code on the keyfob remote that you've programmed into it to turn it on or off.

What is the range?

As shipped, the typical range is about 30'.  You can solder a small helical or wire antenna to the receiver module to extend it to about 100' if you want, but most people will be quite happy with it as is comes.

How big is it?  How much does it weigh?

It's about 2.5" x .9" x .4", and weighs just under an ounce.  It will fit comfortably into most AV bays 2.6" or larger, a bit tighter but still doable in smaller AV bays, theoretically you could put it into a 24mm (BT50) rocket.  Since most rockets with electronic deployment are at least 38mm in diameter, you should  have no problem fitting it into just about anything you're likely to build.

How much power can it handle?

The MOSFET in the Remote Switch is rated for 2.8A continuous, 8A in peaks.  The sustained power dissipation is about 1/2 watt, which is much more than any deployment controller that we're aware of uses.  The solder pads for the MOSFET are extra large to help provide additional heat-sinking; we've used it to direlty fire Estes igniters with a 2S LiPo battery, so we're confident that it can handle whatever you give it.  Naturally, you should thoroughly ground-test any configuration that you're going to fly...

How much power does the switch use?

The switch itself draws about 15 mA.  This powers the RF module, the processor, the buzzer, and the status LEDs.  If you put it into a rocket with a very small battery you might need to account for that current when you figure out how long you can leave it on; the "I'm Alive" chirps will remind you that it's powered up in case you forget to unplug the battery after your flight.

Is is compatible with my XYZ altimeter?

Compatibility with any given piece of electronics basically depends on the input battery voltage of the device.  The Remote Switch requires 6V-20V to operate, so it's compatible with any device that falls within this range.  If you're using a 2S/7.4V LiPo or a 9V alkaline battery with your altimeter, for example, the Remote Switch will be just fine with it.  About the only thing that we know of that it won't work with are a few altimeters that use a 3.7V/1S LiPo for power.  We've tried it... 3.7V just isn't enough for the RF module, which requires 5V to operate.  (Although the processor and other circuitry actually beeps... so close, yet so far.)

The Eggtimer Remote Switch will work with most rocketry electronics that takes an external battery, from 6V-20V.  Compatible products include altimeters by Eggtimer Rocketry, Perfect Flite, Missile Works, and many others too.  If the altimeter has an integral battery you cannot use it, because the switch inputs generally complete a circuit from the internal battery.

How do I know if it's on or off?

There's a buzzer on-board that's used for several types of notifications.  It beeps right after you program it to tell you that it "took".  It beeps to let you know when you've just turned it on or off.  It also gives out a short beep once every 15 seconds to let you know that the battery is connected; one beep if it's off, three beeps if it's turned on.  The buzzer is loud (and annoying... intentionally) so you can't miss it.

Will it interfere with my tracking transmitter or altimeter?

Nope.  The Remote Switch is only a receiver, it doesn't send out any signals at all.  It's on the 315 MHz "remote control" band, typically used by garage door openers and things like remote doorbells, and the keyfob transmitters typically have a power output of only a few milliwatts, so the chance of it interfering with anything at all is virtually zero.

Will it work with a carbon fiber AV bay, or one with steel allthreads running through it?

Due to the limited range that the Remote Switch is designed to be used, CF or allthreads don't really present a problem.  You might find that a CF airframe does limit your range a bit, but you'll find that if you're within earshot of the buzzer then you'll be able to turn it on and off with the remote.

How secure is it ?  I don't want somebody turning my AV bay on accidentally, and I don't want to mess anybody else up either...

With eight 4-button codes, there are over 65,000 possible combinations.  We recommend that you pick a code that's random (i.e. don't use "ABCDABCD" or something obvious like that.   Given the large number of codes and the relatively short range of the transmitter, the chances of you turning on somebody else's Remote Switch or having somebody else turn on (or off!) yours is extremely slim.

How hard is the kit to build?

The Remote Switch uses almost all surface-mount components, they're large by SMT standards so they're definitely within the realm of being hand-solderable.  We made the pads on the PC board extra large to give you some wiggle room in mounting the components.  We DO recommend that you have prior experience with building electronic kits and/or gadgets, and you'll need the right tools too (see the Assembly and User's Guide).

How much is it?

The Eggtimer Remote Switch kit is $16, plus $2 for US domestic ground shipping.  This includes everthing that you need to build the Remote Switch, including a 4-position terminal block if you choose to use it.   You'll need to provide a "pigtail" for your battery, and also a keyfob transmitter; we don't sell those.

Why don't you sell the transmitter?  Where can I get one?

There are a number of different styles of transmitters, and they're a commodity item, so we don't provide them.  You can find them on eBay or Amazon by searching for "315 MHz 4-button RF remote".  Typically, they're under $5.  Make sure that they're based on the Princeton Technology PT2262 encoder, and you'll be fine.  You will only need one transmitter to control as many Eggtimer Remote Switches as you have; since you can set over 65,000 different combinations it's unlikely that you're going to use them up (unless you set them all the same, of course!).