Timer and Switch for Off-Grid Projects

This post will show you how to schedule an off-grid lighting (or a fan, pump etc) to come on and off on a daily schedule without the hassle of programming an Arduino or other micro-controller.

We pair a Drok relay board (real-time-clock, and relay module to be more specific) as the timer and switch in our off-grid grow-light system. The light will run from an always-on IoT Battery Pack like our V50 and the battery will charge from a Voltaic solar panel.

You will be able to use this template to design your own unique projects.

Applications Where a Timer is Useful

Chicken coop lighting
Grow lights
Small water pumps
Animal feeders
Fans

Equipment for Power and Switch

The Drok board requires no code so it is quick and easy to program. It has a nifty on-board battery, so that it never loses memory of our set schedule and it has a 24hr clock which even keeps track of the day of the year.

Assuming your project is off-grid you will need an Always On battery, solar panel, and USB Touchlight (or any combination of our USB power banks and 6V solar panels which are all available on our website). The Always On battery is extremely important as most power banks will shut off if there isn’t anything drawing power. Our batteries are designed to stay “Always On” and are ideal for long term, low power applications.

You will also need a few specific wires and connectors to complete the setup (linked below). We also have waterproof cases and mounting brackets for a full solution.

Voltaic components and Drok board prior to assembly.

Deciding on a Timer Schedule

In our case we want the relay to open from 4am to 6am and 6pm to 8pm, to give our plant some extra light in the long New York winters.

The Drok board can set up to 5 daily time periods.

The time periods are designated PE-1 to PE-5.

So we will be using PE-1 for 4am-6am and PE-2 for 6pm to 8pm.

The Drok board also has 5 distinct modes, P1 to P5, to chose from. We will only use the daily timer mode, P1, which is probably the most useful. It will switch the relay at a specific time everyday.

To interact with the board you need to supply it 5V via the Micro USB port. After the inital setup, you do not need the Micro USB connected if you setup the wiring as indicated below.

Step By Step Setup

Firstly set the time and date for the board (detailed instructions here).

Then follow the instructions below using the SET and the UP and DOWN buttons (detailed instructions here):

Enter the PE-1 time period
Set the P1 mode
Set OPE to 4am (or whatever times you need for your project)
Set CLE to 6am
Confirm the PE-1 time period
Enter the PE-2 time period
Set the P1 mode
Set OPE to 6pm
Set CLE to 8pm
Confirm the PE-2 time period
Done! And you could add up to three more daily time periods.

Read about the other modes on the Drok website. They include turning the relay on and off on specific days in each month, or for a certain time period on a certain day, or to even pulse the relay on and off. There is also an on-board buzzer that may come in handy.

Wiring Diagrams

Voila!

That’s it. You now have an off grid solar-system set on a timer.

Now you could swap out the light for a small water pump and turn this from a grow-light system into an off-grid aquarium if you had the inclination. Or perhaps an ultrasonic transducer for your next camping tent humidifier!

Getting Creative with the Drok Board

Since the sunrise and sunset times change so dramatically over the course of the year you will need to reprogram your Drok board every so often for a grow-light system. There doesn’t seem to be a way to program a shifting daily schedule.

However we thought about this and came up with a clever way to essentially use your solar panel as a light sensor:

Ensure relay is set to Normally Closed
Set your PE-1, P-1 to be open all day. OPE: 00:01 and CLE: 23:59
Wire your panel to the Input + and Input –
Wire your panel to the battery as well (you will need a splitter)
Wire your load just as before

Now when the sun sets the light will come on automatically.

So as you have seen the Drok relay board is a simple but useful tool with tons of real world applications.