After noticing Exfso's artificial star I thought some IISers might be interested in a cheapo dew heater controller. I bought my dew strap from scopestuff in the US to save the hassle of making one as they were only $35 US. Dew controllers however are much more expensive so I opted (for power efficiency reasons) to make a simple PWM controller which I found on the following website.
http://www.backyard-astro.com/equipm...l#Anchor-49575
For those interested on the site there is also a simple (and elegant) dew heater using nichrome wire and a piece of silicone tube. I used veroboard rather than making a PCB and put together the beasty in a couple of hours. The unit switches slowly to minimise interference with tracking electronics and is about as simple as it gets. I'm not really sure of the exact cost as I already had the jiffy box, knob and power socket, but it cost me well under $10 for the bits I had to buy. I used a 2.2 microfarad cap in lieu of the 1.5 and a BD681 in lieu of the TIP120....Next project is a multi port model.....
