DIZZY DOUG TV

By 

Donald E. Fulton (Stoneham, MA USA) –

  

This joins the radiometer and 4″ prism as one of the vital sun toys that all must have. It’s a fun design with a transparent case, exposed motor, different painted gears, and deactivate rotating crystals. It looks to be quite well made, and I was pleased to find that its generous built-in suction cup does a excellent job. Up accurate you hear a modest whirring sound (not objectionable) from the motor and high alacrity gear, but from crosswise the room it runs silently. Its alacrity doesn’t vary with the intensity of the set alight, it either runs or it doesn’t run. Occasionally it will click for a few seconds as the shadow of the sun passes over it.

I saw one reviewer who said the release crystal unit worked fine, but the double unit was underpowered and would barely rotate in sharp sunlight. I don’t find that to be the case at all, mine rotates even when the sun is incomplete obscured by clouds. As I write, it is late on a winter day in New England with the sun low in the sky at 60 degrees off perpendicular, and my double unit is subdue running. I experimented and establish it would even run when the solar cells were illuminated from the back!

Minor negatives — Compared to the one huge sharp solar spectrum a 4″ prism will toss on the wall, the spectrums from this thing are sweet small and dim, even if the compensation is that here are many of them and they sweep nearly the room. When the sun is at the aptly angle, you have to expect that some of these ‘rainbows’ are vacant to pass over your eye, so you get a modest enthusiasm now and then. It’s more complicated than a prism or radiometer, so it’s doubtless not vacant to live as long.

For persons attracted technically its solar panel is 4 cm x 2.5 cm = 10^-3 m^2 and looks to be five (1/2 V) cells in run. In view of the fact that the power of sharp sunlight is 1,000 w/m^2, if inexpensive solar cells with efficiency in the 5% to 10% array are used, the productivity power available to handbook the DC motor would be 50 to 100 mw, or 20 to 40 ma @ 2.5V.

update — It’s now nine months in view of the fact that I place this on a dialogue box by the vacuum chump and it’s never fallen off! Subdue facility fine too.

update2 — Well after two being, it’s screening its age. One crystal broke off when it fell and the gears are now sticking. I just prearranged a substitution.

More technical— When my new one at home, I took away from each other my ancient one to look at the motor, which subdue facility. (I am a motor control persuade.) The motor is not a DC motor with brushes, which is excellent as brushes wear out. It is a brushless AC PM (permanent pull) motor that a fiddle with test shows will spin in either management (at unequally 200 RPM). The 2.5V from the solar cell is converted to AC by a tiny path board mounted higher than the coil. The board’s committed component(s) is enclosed by glop, but it is doubtless a release IC clocked by an external crystal, which seems like overkill.

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