Archive for March, 2009


Tweeting a Water Rocket Launch Day

The last couple of days has been spent testing the technology to provide updates and pictures live from a launch day.

Good news is that we have the technology working now, we send updates to our twitter account as well as the updates appearing on this website. You can see from the left that the last tweet has a URL for a photo that was taken with the Nokia N95 camera and uploaded using Vodaphone’s 3G wireless network.

Even more interesting is that I can receive tweets on my mobile as replies to the messages and photos I upload from the launch day. If you are following on the twitter web site or on your phone … This means a live interactive launch day :)

Just need to get the wrocket ready to launch. The pic I have uploaded is a pic of our first 3 bottle wrocket.

Now for more rocket updates :)

Posted by on March 12th, 2009 4 Comments

Webserver update + Twitter !!

I have been doing a few things to the website today, not so much wrocket stuff, but in preparation for a unique water rocket event . more below.

This website runs on a webserver that’s in my garage, its runs WordPress using Apache and MySQL on Linux which is a virtual machine on a VMWare server. I added another 1GB of RAM to the VMWare server tonight to give the web server virtual machine more RAM. In English that all means that the web server performance is better :) which is good.

We get about 100 page views a day when Im not writing posts and 200+ when I do, so this should be good for everyone.

Another thing I have added, which admittedly I have been slow to take up on is twitter. Twitter is basically a way of getting real time updates to people via the web or mobile phone SMS’s. I thought I would trial this technology for the first time in the water rocket community and Tweet (send messages) from a launch day. This way you will be able to get updates in real time as to how its going.

I plan on using my Nokia N95 to send the updates and you can follow along on my website (the sidebar now has the twitter updates) or directly on my twitter page

or if you are a regular twitter user, you can get SMS updates to your mobile phone …

It seem interesting technology and while this is probably just a proof of concept of the technology (in our community anyway), it is interesting none the less. I will give quite a bit of warning before a launch day … but keep a watch on this blog and the twitter feed at the bottom of the sidebar

—> over there …

Posted by on March 11th, 2009 3 Comments

Flight Computer

Ive had a bit of a break from Water rockets since December, but my other projects are getting to be finished so I can put some time back to water rocketry.

One of the decisions I came to over the break was that I needed to increase my recovery percentages. While I put a lot of work into the tomy timer design it just didn’t give a high percentage of recovery. I calculated I was running around 50 – 60% of a successful recovery. I also deduced that it was the releasing of the elastic band from the timer that was the trouble. I could get it 95% of the time to release while testing it on the ground, but in the air with the force of the air rushing by was a different story. It was hard to test in this scenario. So I ended up loosing a lot of wrockets disappointingly only getting to fly a wrocket once after building one.

I have had my eye on George from Aircommands computer deployment system, and when he had a new batch ready I jumped at the chance to get one. I used trusty paypal that evening and george shipped it the next day.

I got the model with the onboard gravity switch for launch detect

Aircommand Water rocket Flight Computer v1.6 with launch detect

Aircommand Water rocket Flight Computer v1.6 with launch detect

I also had to get some micro servos to use with the computer. There are many available from Hong Kong on Ebay, but I ended up getting 4 from an Australian ebayer for a few dollars more, but had it within 2 days.

The specs of the servos I got are

* Nylon gears
* 3 pole wire
* Weight: 8 grams
* Torque: 1.4kg/cm@ 4.8V and 1.9kg/cm@ 6.0V
* Speed: 0.1 sec / 60o at no load
* Operating Voltage: 3.0V – 7.2 V
* Dimensions: L 23mm x W 12mm x D 26mm
* Universal RX plug

Micro Servos with battery for scale

Micro Servos with battery for scale

I had a little issue with the servo motors running for 2 seconds after the servos had swung its full arc. George was great and gave me advise of which setting to change in order to get this right. ALl is working well now. Here is a video

Posted by on March 10th, 2009 5 Comments