DIY Dew Controller

By: Vlad Fedosov


Having an evening of observing ruined by you objective dewing up is never fun. Unfortunately, spending over $100 on a dew controller is never fun either. After doing a bit of research online I was able to put together my own dew controller that works just as well as the commercial units costing over $100. This unit is compatible with any commercial dew heater straps. It is made to control two separate straps but this design can easily be adapted to do more straps.

DIY Guide:

To begin this project I did research online at a variety of websites and forums that gave me the basic info of how to get a working dew controller in a way that is not overly complicated and relatively inexpensive. The basic components needed to make this dew controller are outlined here:

The above does not include a project box as I own a 3d printer and I decided to make a box that is 100% customized for this applications and is ready to have all the electrical components installed. Here is a guide on the basic assembly of the dew controller:

1) Start by taking the dimmers apart. You will need to remove the know by pulling up on it. Remove the wire connector by pulling out on it. Remove the (4) Philips screws. The last thing holding the box together is the nut on the dimmer switch. At this point you can take the box cover off and remove the small Philips screw holding the circuit board in.

2) Assemble the bottom dew controller box: Install the (2) RCA plugs, DC plug, and the (2) dimmer controllers. You will also want to plug the LED's into the top of the dew controller.

3)Wire up all the components. Refer to the diagram on the left. It is a fairly straightforward circuit(note that I had the negative wires from the RCA plug running to the incorrect side dimmer plug in this picture). The positive wire goes to the inner pin on both the DC plug and RCA plugs. Once the wiring is done then screw the dimmer controls to the top panel and reinstall the dimmer switches. (note that you will want to use a fused power supply or add a fuse to this design)


It takes very basic electronics skills and a bit of tools to make one of these at home. If you enjoy a DIY project and/or cannot get yourself to spend over $100 on a commercial dew controller then this is the solution for you! If you would more info or have questions about the project feel free to email me. I also have a few sets of all the components needed to make one of these and can 3d print an enclosure if you want a really easy way of making one of these. Email: