Untitled Document

The Diary of an IVARC Project

(Flashing LED badges for FLAME 2006)

What comes first ? The chicken or the egg, or in this case, the blue flashing LED or the plastic badge frame ?

“You won’t believe how many photos I had to take of the badge

to get one with both lights on !! ”

Often good ideas are born through pure serendipity, the right things happening at the right time. So it was with this project. I (Brian G0UKB) had previously bought a job lot of LEDs off a dealer (Christian Slater of Slatec Electronics) in Yorkshire and was delighted with the product and price. So when Chris e-mailed me with a special offer of some new LEDs he'd got for sale I thought it worthwhile taking a look. He'd got ultra-white and ultra-blue LEDs, blue flashing LEDs, RGB LEDs with a built in device to cycle the colours, violet and ultra violet LEDs – an impressive collection. What's more the special prices were good – about 30% of his normal retail price, so, naturally I ordered 10 of each just to see how useful they might be.

At the same time Liz, M0ACL, was wading through a new craft catalogue looking for ideas for Girl Guides when she discovered some lovely acrylic badges: 2 part that popped open to allow you to put your design inside. So she ordered a sample too.

The badges arrived and looked ideal for a children's project – but what ? I think it was Liz that suggested the possibility of a flashing LED if only we could find a battery suitable. It looked like a 16mm CR2016 might be a good fit, but would 3v be enough to flash an LED with built in current limiter and flash mechanism ? The answer was ‘yes’, but the old flashing red LEDs just didn't look anything special – until Brian remembered the order from Slatec with its blue flashing LED. My goodness was it bright ! All Liz had to do was design a badge logo to incorporate one or two of the LEDs and we had the 2006 Flame electronics project.

Well not quite all – first there was the simple matter of stocking the project. CR2016s are £1.99 in Maplins, the LEDs were 35p each and the badge was 35p too, so we were looking at nearly £3 – way too much for a badge. I immediately set an aggressive target of £1 and went Internet searching.

The badges seemed to be unique to the London Badge company (curiously enough based in Fareham) so there was little we could do to reduce the price except hope for bulk discount – the plan was to kit 300 badges each with two LEDs and a battery. That many LEDs would work out at 30p each, but Hong Kong suppliers on Ebay seemed to suggest we could halve that cost, so I ordered 10 of 3 different types from different suppliers. To my surprise none worked off a 3v CR2016 ! Actually one of the 3mm red/blue flashing ones was on the edge of working – about 30% of the stock worked and the rest just wouldn't fire up. So back to Slatec with a grovel and an order of 600 driving the price down to 25p each.

Just the batteries left, and here Hong Kong and Ebay did come up trumps – pricing around we managed to get Chinese CR2016s for the princely sum of 11p each ! Of course these weren't Duracell, but a test sample (hint – never buy 600 batteries off Ebay without having bought a sample of 10 or so first) proved they would drive the blue flashing LEDs for approx 8 days – well enough for our needs. Just to be sure of getting a full week out of the badge we decided on one battery per LED rather than running both LEDs from a single battery.

So all sorted – total cost: Badge 31p, 2 LEDs 50p, 2 CR2016s 22p – just 3p over a somewhat crazy target.Well not quite all sorted. Now we get to the stage where the real strength of IVARC comes in. It's easy for Liz and I to have an idea and source all the components but at this stage that's all we had – an idea and a heap of components.

In comes the final pair of the group that puts together all of the Scout and Guide projects – Mike, G0WIL and Sheila, G0VNI. Mike never gets phased – we say we have this idea and no matter what it is he makes it work. In this case the project involved accurately drilling 600 holes in a brittle acrylic that cracked if it was in the same room as a drill bit. To be honest I expected about a 20-30% fail rate with cracked and broken badges – the fact that Mike had 4 failures in 300 was absolutely amazing. I saw the jig that Mike had made to support the plastic casing and also provide the template to ensure the hole positions were consistent – a nice piece of engineering.

Sheila is the process manager. She takes the idea and the components and optimises construction. A bend of an LED leg just so or positioning sticky tape just a few mm differently makes a complete difference to just how easy the construction will be for young hands, and Sheila has a rare talent of being able to tune and optimise any project – our Flame 2002 amplifiers would never have been built in the allotted time had she not intervened and completely revised the assembly process.

Now we were ready ! And what a hit the badges were – we sold all 300 at £1 each and had queues in the radio room for people wanting to make them. A casual stroll through the Foxlease campsite after dark revealed just how many flashing blue lights there were – it was amazing planes didn't attempt to land there. So the success of nearly 3 months planning and buying equipment and the month that Mike spent drilling 600 holes and the final project tuning sessions was obvious in the delight of all the youngsters who actually built something exciting that they could brag to parents and friends.

So if you are planning a project, even one as simple as just pressing LED legs against a battery, don't underestimate just how long it takes from idea to kitted end result and don't underestimate the talents required to really polish the project.

A final note – it took several months kitting out just 300 simple badges. Spare a thought and a note of thanks for folk like Tony KB9YIG who is running the Softrock projects. Single handedly he has kitted at least 5 kits with runs of 1000+ including printed circuit board and SM components. An outstanding feat and it's folk like Tony who are keeping the hobby and spirit of amateur radio alive today. My hat comes of to him.

Brian G0UKB