Isn’t it great when the Postman turns up with bulky looking package for you? Ok, perhaps some packages, especially those with official government looking crests on them may not be too welcome, but generally – eh? Anyway, I was certainly pleased to receive this particular packege. It contained the main component resin parts of the Stasis Tube model kit – and I had been trusted with it. Not sure that was necessarily a sensible thing to do, but it was too late now!
I carefully unpackaged the kit and dry assembled the four component parts to see for the first time “in the flesh” as it were, just how much room I had available for mounting the electronics and to check the fit of the main adapter board in the base component. What followed can only be described as a “Woohoo!” moment, when it became apparent that everything fitted and fitted well.
The next task was to position the magnetic sensor on the inside of the model in such a position so that it was operable from the outside. I found the best position to be on one side just below the top of the model. Now, I had been loaned the model with the strict instructions not to use glue or anything permanent to assemble it as the very same kit was to be built and painted by a real model maker – in other words someone who could build it without messing it up – charming!! Somebody has seen my modelling skills obviously! Not being able to use glue meant using clear adhesive tape, i.e. Sellotape. Wonderful stuff is Sellotape, provided you don’t stick it to itself or body parts.
After taping the sensor in place, it was now down to positioning the upper and lower external lights. Now, I say external, but they are actually mounted internally and there’s necessarily not a lot of room for the lower light. I had found a manufacturer and supplier of pre-wired SMD (that’s surface mount device) LEDs which I hoped were small enough. Certainly for this trial fit, they were more than adequate but I have since been in contact with the supplier to ask if he could possibly make them any smaller. In his own words he loves a challenge – so I think I’ve certainly given him what he loves! The upshot is that the production LEDs will be tiny and a lot easier to fit.
Right, all parts in position and sellotaped into place, time to plug in and view the result. This unit runs off just 5 volts so we’re powering it from a USB wall charger via USB charger cable. Due to using the three data lines of the USB unconventionally, it’s not feasible to power the model from a computer. Those three data lines have a planned use – later ( 😉 ). I powered up the unit and ran it through all the functions. The lighting looked pretty spot on to what I’d planned but there were couple of issues to be addressed. First the external lighting flashing rate during the Alert phase looked wrong to us, so I’ve since reprogrammed them to produce a more realistic tube failing effect.
The second issue could potentially have been a more serious issue. The test has proved that the strength of the neodymium magnet used to switch the magnetic switch wasn’t strong enough. Tripling up on the magnet gave us enough strength, and that’s what I used for the testing, but I had to make a few phone calls to make to the magnet supplier. Phew, panic over, they can supply us with a magnet that is slightly thicker and larger in diameter that was as strong as the three magnets I had used for the test, but reassuringly they will still be thin enough to use in the access card.
Encouraging test I think. I was able to finalise the length of interconnecting cables and the bulk order has been placed with the cable manufacturer in South Wales. All that remains now whilst I still have the kit is to compile a set of instructions on how to install the electronics kit into the resin model.
Until the next time….