Earthshine Design Blog

Sorry it’s been a while since I lasted posted on the Blog. The orders for November and December have gone through the roof and trying to keep up with demand has been tricky to say the least. This has meant any projects such as the High Altitude Balloon Project have most definitely been put on hold until things calm down in the New Year.

So, have a great Christmas and all the best for 2010 and hopefully things can get back to normal in a few weeks time.

Since my last post have found out that GPRS/GSM modules or mobile phones won’t work above around 2500 metres so the idea to Twitter from the balloon is out of the window. Also, doing a bit of research found out that the RF Modules I purchased are not suitable for HAB. So, have replaced the RF Modules with an NTX2 from RadioMetrix. This is a 10mW FM transmitter on 434.65MHz and with a sensitive enough transmitter will get a range of several hundred miles. So, have purchased a second hand HAM Radio transceiver, a Yaesu FT-790R, which picks up the 70cm HAM Radio band (430-440MHz). This will be used to pick up the signals from the balloon.

The radio part of the project I was expecting to be difficult, but James Coxon from the UK High Altitude Society gave me a one-on-one workshop on using the RF Modules, transmitting data, receiving the data and decoding it, etc. at London Hackspace about 2 weeks ago. This was a very useful and informative workshop and it was this that made me realise that the radio part of the project is actually going to be very simple. So I will soon be carrying out some tests of the NTX2 to send GPS data to the receiver.

Also, have replaced the cameras with a Canon A560. The reason for this is a) I got one cheap on eBay (brand new) and b) they can be used with the Canon CHDK which is a non-permanent firmware that allows you to get extra functionality out of a Canon Powershot camera. The CHDK allows scripts to be uploaded to the camera, so for the flight, the camera can have a script uploaded to it to make it turn itself on, take some still shots, take a minute or two of video, then shut down and repeat evert 5 mins, or something like that. This means there is no need to hack the camera controls and no need for the microcontroller to waste power controlling the camera as the camera can be programmed separately to take the images. Plus the A560 has a higher resolution than the Ixus 400 (S400).

So hopefully this weekend, if I have time, I will be connecting up the NTX2 transmitter and carrying out some data transmission tests. Once I have that working the next stage is to connect up the GPS module, successfully get data from it, then connect it up to the NTX2 to transmit the GPS data to the receiver.

Further updates to the Arduino based HAB Project. Been frantically bidding on eBay for cheap parts. Managed to get hold of a Canon Ixus 400, which is a nice hackable camera. Also got an old Nokia 5110 phone which can be hacked to send data to and from the GSM module on board to enable sending of SMS messages. So, camera sorted and phone sorted.

Had a brainwave yesterday and decided that I will be getting the balloon to send Twitter updates every few minutes giving it’s position, altitude, speed, etc. Anyone can send a Twitter update from their phone by sending an SMS to the Twitter number so the balloon will be set up with an account to enable it to Tweet flight information.

Have found out that the GPS Unit I got from Maplins is no good for a HAB Project as it does not correctly implement the COCOM Limits. From Wikipedia – “In GPS technology, the phrasing “COCOM Limits” is also used to refer to a limit placed to GPS tracking devices that should disable tracking when the device realizes to be moving faster than 1,000 knots (approximately 515 m/s or 1,852 km/h) at an altitude higher than 60,000 ft (approximately 18,000 m). This was intended to avoid the use of GPS in ICBM-like applications.”. Unfortunately the manufacturer of this GPS module, the same as most of them, has interpreted this incorrectly and made the unit shutdown if EITHER of those conditions are met (Yeah how many ICBM’s can travel at over 60,000 feet but at only 5 m/s? Come on!).

Fortunately, there is a GPS module company called Trimble whose modules implement the correct COCOM logic and I have therefore obtained a Trimble Lassen IQ GPS module for the project.

Trimble Lassen IQ GPS Module

Also, arrived in the post recently are the various RF Modules I am going to try out. I have two types of 433MHz modules and one 173MHz module. All are licence exempt and will give a range, with the correct receiver equipment, of hundreds of miles, despite being only 10mW in power.

433MHz RF Modules

I will be experimenting with the GPS Module and the RF Modules over the next few weeks.

One of my hobbies is astronomy and I am the Observing Officer for the Orpington Astronomical Society. At our last monthly meeting the Chairman’s presentation included a brief section on the kids from MIT that sent a camera to the edge of space in a balloon for less than £100. The story can be read HERE.

This story, coupled with a recent find of a cheap GPS module from Maplins (Special Offer of £14.99 – Thanks Ian T for the heads up) has inspired me to think about doing a High Altitude Balloon Flight myself. This has lead to lots and lots of research lately about GPS units, radio modules, balloons, parachutes, cameras, etc. Obviously, the brain of the unit will be an Atmega328 loaded with an Arduino bootloader. What I want to do is relatively easily achievable, the tricky bit is making sure the payload returns to earth safely and is able to be recovered. This means very careful thought and planning about what kind of equipment goes into the payload, what backup systems are used and how the unit is tracked and recovered. So far 95% of the Project has been just research, apart from obtaining the GPS Unit and figuring out how to read the NMEA data from it. So far this has been a simple serial read off the module and the following video shows you how I did that. I will post up more details as the project progresses.

Now i’ve obtained a new camcorder (cheap standard definition one for now) I have finally got around to making a video of the BlokClok concept. So now you can see what it is all about.

Arduino driven clock concept. Unique and abstract concept using an 8×8 RGB Dot Matrix Display. The time is indicated using blocks of colour. The central 6×6 grid is split into 4 x (3×3) grids and each 3×3 block is a different colour. The number of LED’s per 3×3 grid indicate the digit. i.e. if the first 3×3 grid has 1 LED lit then the first digit is 1, the second has 7 then the 2nd digit is 7, etc. The top two grids are the hour digits and the bottom 2 the minutes. Around the edge the unused LED’s have a moving light that shows the approximate position of the seconds.

The display is driven by 4 x 74HC595 Shift Registers controlled from the Arduino. Each register controls a colour (r, g & B) with the final register multiplexing the rows. The time is obtained from an DS1307 Real Time Clock chip with battery backup so that the device can be powered down and will resume at the correct time when powered back up again.

The blues and purples look the same on the video which was done using only a cheap standard definition camcorder. To the human eye they are very clearly different colours.

Stage 2 will be to make a PCB for this with the same footprint as the Dot Matrix Display so it can be made small and light. Then maybe make some kits. I will post some schematics and code on the website soon – www.earthshinedesign.co.uk

Enjoy…..

There has been some minor changes to the Starter Kit. Firstly the power supply is now a 12v one instead of 9v. This unit is smaller and lighter than the 9v version. Secondly, the Roboduino Duemilanove boards now all come with the Atmega328P chip as standard. The 168 chip is slowly being phased out by the manufacturer so all boards from now on will include the 328 chip.

Sorry for no posts for a while. You would not believe how busy it has been recently. We are taking orders from training centres and colleges and it has been breakneck pace to keep up with the orders and to keep components in stock. Plus i’ve had a few personal events that have taken up time also, including a 45 mile bike ride on Sunday to raise money for Bowel Cancer UK. If you would like to donate something, no matter how small, please go to http://www.justgiving.com/matts-mates2009/. Thanks in advance

I’ve really been wanting to get on with some Arduino projects recently but have just not had the time. There are some old projects I need to post pictures and other details of online too. Sorry for the Blog neglect. Once things die down a bit i’ll catch up with the Blog posts and project details. It’s great business is booming but at the same time I wish there was more time for projects and other ‘cool stuff’.

As some of you may know, I’ve been working on a clock design over the last few months. It made a brief appearance on the BBC News magazine page in an article on the London Hackspace (I took the project to work on that night). The BlokClok is a new clock design that, as far as I can tell, has not been done before. It’s a bit of fun really and was a nice project to work on. I will post up a video very soon so you can see how it works.

We are currently working on some different ‘flavours’ of the Arduino Starter Kits. The kit we do at the moment will become a Standard kit. We will then introduce a Basic kit and an Advanced Kit. The Basic kit will have less components than the standard kit, but be enough to understand basic input and output with an Arduino. The Standard Kit will remain as is at present. The Advanced Kit will also include an LCD Module, an LED Driver IC and some 7-Segment Displays.

We hope to have these in teh store in about 2 weeks time. Watch this space.