Right now I'm building a night vision kit. It's based upon an ex-military night vision image intensifier/converter tube that is responsive to deep infra-red light. By using an IR illuminator, a scene that cannot be seen in the dark normally can be observed via the screen of the night vision tube. The tube runs off approx 15 kV and also requires a focus voltage.
I bought the tube, including a small inverter-type power supply kit, object and eyepiece lenses from Oatley Electronics, however they have sold out of these tubes as of 3/4/99. They may offer other night vision tubes from time to time, however.
At present I have assembled and tested the EHT power supply, and have successfully powered the tube from it. I have also purchased some PVC plumbing fittings and pipe to house the tube and lenses in, and have used a separate ABS project box for the power supply. If time permits I will try to get some photos of the finished viewer on the site but I am very busy.
Well, after a hiatus of several months, I've finally found the time to start a new project. This one is an emergency/general purpose light based around the backlighting tube out of a surplus LCD display (see Electronics Australia April/May/June 1998 for more information or contact the designer of the kit, Oatley Electronics). It runs off a small inverter-type power supply and produces a very bright white-light output at a very low power consumption. For my application, I'm planning to mount the tube on a zippy box and run the inverter off a surplus 12V lead-acid cellular phone battery (which I bought from Oatley as well) so that it can be made completely portable. Stay tuned...
By the way, I did finish mounting the night viewer and testing its response with an IR remote control, with positive results. The next step is to provide some form of IR illumination so that it can be properly used in the dark. More on this at a later date (if time permits...)
The backlight inverter kit has been completed and provides a very impressive white light output. Using a 2.3 AH battery, I have been able to obtain run times of several hours without any noticable dimming. The only problem I have encountered is that the 9V CT to 240V step-up transformer makes a high-pitched whine when run at the frequencies the inverter module generates (around 9 kHz in this case). Although this is not surprising as these transformers are really designed for step-down operation at 50 Hz, I have read in Electronics Australia that this can be fixed by wrapping the core in felt (this helps to isolate the 9 kHz whine from the metal surround). Perhaps I'll do this in the future, otherwise I'll just have to put up with it...
Anyway, I've started another kit now: this one's a 300W DC/AC inverter of the type used to power mains equipment in remote situations. Again, I bought the kit from Oatley for about $90 (including the step-up transformer and a reservoir capacitor). I've just finished assembling the PCBs and have just bought a good metal case to house it in, so the next step is to mount everything, wire it up, and give it a trial run. More on this once I've got all my schoolwork out of the way :)
Well, the 300W inverter is finished and is running very nicely. I haven't been building much lately, although I did build a simple battery charger kit from Oatley a few months back. Most importantly, I've just finished building myself a decent power supply; something I have been planning to do for ages. I built it up from an Oatley kit, and put it in a large instrument case I bought from Dick Smith. It's rated at 3A continuous and can be set from about 1.7V - 14V... plus it has short circuit protection. To test it out, I hooked it up to a length of nichrome resistance wire that was supported at either end by a nut and bolt mounted on a baseboard.
Anyway, the next project is a powered cooler based around an old esky and a Peltier device I bought from Oatley (for more information, see Silicon Chip Sept 99 or visit the Oatley website). I bought the esky and a couple of large heatsinks for the Peltier at a garage sale for $4 all up... bargain!) Now it's just a matter of finding the time to put it all together...
Last updated 9/05/00
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