Eggtimer Rocketry


What is the Eggtimer WiFi Switch?

The Eggtimer WiFi Switch is an electronic switch and monitoring system that allows you to turn on and off your AV bay electronics (typically, a deployment controller/altimeter) remotely using your tablet,phone, laptop, or any other WiFi/browser enabled device.  It also monitors the battery voltage and deployment channel continuity status of your altimeter.  All this is done via secured WiFi to any WiFi-enabled device with a browser.

So I can turn on my AV bay electronics with my iPhone?

Yup.  Or Android, Windows, or whatever other WiFi/browser device you have handy.  We haven't tried it with an Apple watch yet, but we imagine that it would work with that, too.

Does it require Java or .NET on my device?

Nope.   Everything is done with good ol' HTML.   We don't even use Javascript or PHP.  It's compatible with every brower ever made in the past 15 years.  Various browsers might display the fonts slightly differently, of course, but the page will display (and work!) correctly nonetheless.

How does it work?

Simple.  You connect your phone/tablet to it via secure WiFi, navigate to its home page, and you get a web page with the status of your WiFi Switch's output, the battery voltage, and the deployment channels.  To turn it on or off, you simply enter a 4-digit validation code and click the Submit button.

What it somebody else on the range has one?  Can they connect to my unit accidentally?

Pretty much no.  Each WiFi Switch has a unique SSID name, and the 8-digit passkey for each one is randomly generated and non-changeable.  There are 100,000,000 different passkey combinations so somebody would be hitting the lottery if they got yours.

Can I have two WiFi Switches in my AV bay for my redundant electronics?

Yup.  Each one will have a different SSID/passkey, so you can connect to them independently and know which one you're turning on/off.

What is the power capacity?

We've seriously over-engineered it, the FET on the WiFi Switch is rated to 13A continuous and nearly 40W, with bursts of over twice that.  The chances of you overloading the switch are just about zero.    

What are the power requirements?

Because of the relatively high power draw of WiFi, we recommend a minimum of 300 mAH 2S/7.4V LiPo battery.  The drain is about 85 mA (yes, that's a lot... like we said, it's WiFi) so you'll get about three hours from a 300 mAH battery.  Bigger is better, of course...

What brands of altimeters does it work with?

We've used it with our products, of course, but we've also tried it with altimeters from Missile Works, Perfect Flite, and Featherweight Rocketry.  We'll post connection diagrams up on the Support page as we get a chance to evaluate the WiFi Switch with other electronics... it's primarly the continuity hookups that's different between one device and the next.

How does it sense igniter continuity?

You connect a 2-conductor pigtail for each igniter from the WiFi Switch to your altimeter's power and/or igniter terminals.  WHICH terminals you use depends on the altimeter.  The idea is that it bridges the igniter's switched lead with whichever battery terminal is switched on by the deployment electronics, so a trickle current flows through the igniter and the detection circuitry.  If the igniter is open, no circuit so no continuity.  The resistance of the bridge is relatively high (over 10K ohms) so it's sending less than 1 mA through the igniter.

Most non-Eggtimer altimeters use FETs in the output circuit, so they generally switch on the "-" side of the battery.  Typically, you'll connect one lead to the "-" battery lead and the other to the igniter lead that is NOT "hot" (i.e. the one that's not connected directly to the "+" lead of the battery).  It's pretty easy to figure this out with a DVM, but we've done that for you with a number of common altimeters.

What is the range?

The range will vary depending on the terrain, construction of your ebay and rocket, and whatever other 2.4 MHz signals may be floating about.  We've tested it open-air to about 200', and flown it from the 100' center pads with good WiFi signal.   Carbon fiber tubing, metallic paint, or a lot of metal in your AV bay (beyond a few allthreads) will reduce the range, but it should still be plenty useable.

How hard is it to build?

Easier than most of our kits.  It's mostly surface-mount, but the passive parts are all 1206-size, which is very large by SMT standards, and the silicon is all at least .050"-pitch.  We DO recommend that you build it with a magnifier, but it's not hard... you should be able to build it in an hour or two.  We include special .020" low-temperature no-clean solder to make it easier.

What 802.11 protocol/band does it use?

The WiFi Switch uses 802.11g on 2.412 MHz, Channel 1.  This channel is available for non-licensed use anywhere in the world,  unlike the 315 MHz Eggtimer Remote Switch (which the WiFi Switch replaces).  We can ship this internationally with no restrictions.