DIY Dew Controller

[trogre]

Hi All. I have just started buying the parts needed for 2 channel controller following Blackwaterskies instructions. I have most of parts needed but got a question about the power socket that attaches to box. I see you can buy 2 sizes (at least), 2.5 x 5.5 mm single hole fixing socket or a 2.1 mm x 5.5mm.

Not sure what size I need to buy, not having seen any of them my gut feeling is the bigger 2.5mm? Once the controller is made I am then turning my attention to a dew strap. As yet not decided to make my own or buy a heated strap but once I do that it is the power source.

I know I need to work out the dew strap power requirement before I purchase a battery. Ideally a rechargeable lithium battery would be best only as this can be strapped to telescope mount and do away with the wire wrap that will happen with a battery on the floor. I only observe for about 2 hours at a time so do not need a battery to run heater all night. The scope is a 8” nexstar evolution so plenty of places to strap battery to. Some searching of forums needed on battery advice before I commit to buying one.

Any help on power socket size to buy for controller would be appreciated.

[MarkyD]

For the power socket it doesn't really matter as both sizes will handle the current.  I went for these instead as they won't fall out

http://www.maplin.co.uk/p/maplin-2-way-audio-locking-connector-chassis-plug-fm50e

Also on the Blackwater skies site beware that the schematic is wrong.  The short lead of an LED is the negative and NOT the positive.  Also the fuse should really be in the positive side of the circuit.

This is my DIY job

 

[trogre]

Hi Mark. Thanks for the link to Maplin power socket and the heads up on led wiring round the wrong way + having the fuse on the positive side which makes sense really.

Had a look at your controller and was expecting something similar but man was I wrong,a work of art, Very neat layout,excellent.

[RichLD]

If you're set on using the standard DC power sockets you've mentioned I'd go for the 2.1mm variant. The majority of 12v dc power supplies I've used have this size of  plug and you never know when you might need to use one in an emergency - using the 2.1mm keeps things a bit more "standard" - hope that makes sense (I'm typing in a rush on my mobile)

Cheers

 

Rich

[RichLD]

Forgot to mention in my last post - the all metal version featured here are really good for this type of project. I find the ones made of metal and plastic are prone to melting when soldering the thick wire sometimes needed for power applications due to the extra heat required, although that could just be that I'm rubbish at soldering 

[Tonk]

You can get 2.1 to 2.5 adapters (and other way round) so you don't have to worry about choices. The 3rd party gear I'm using on my rig (focus controllers, LAN switches etc.) uses both sorts but I'd standardised my power harness with 2.1 plugs. I just added the adapters for the couple of devices that needed it.

Example here: http://www.allelectronics.com/item/dca-7/dc-power-plug-converter-converts-2.1mm-to-2.5mm/1.html - I got mine by walking into a Maplin store