# Timer for lights **URL:** \ **Category:** Uncategorized\ **Created:** [January 1, 2018, 11:38pm UTC](https://forum.xod.io/t/timer-for-lights/348 "2018-01-01T23:38:37Z")\ **Posts on this page:** 10\ **Page:** 1
**Author:** ![alessandrogiannini](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.xod.io/alessandrogiannini/32/931_2.png) [@alessandrogiannini](https://forum.xod.io/u/alessandrogiannini)\ **Post date:** [January 1, 2018, 11:38pm UTC](https://forum.xod.io/t/timer-for-lights/348/1 "2018-01-01T23:38:37Z")
Hi everyone! I need a light to be turned on for a certain amount of hours, and then off for another amount of hours, how can I achieve this? Thank you. ---
**Author:** ![nkrkv](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.xod.io/nkrkv/32/8_2.png) [@nkrkv](https://forum.xod.io/u/nkrkv)\ **Post date:** [January 2, 2018, 12:33pm UTC](https://forum.xod.io/t/timer-for-lights/348/2 "2018-01-02T12:33:51Z")
Hello and welcome! You can use a [`square-wave`](https://xod.io/libs/xod/core/square-wave/) node to cycle on and off phases. Use [`time-to-duty`](https://xod.io/libs/xod/core/time-to-duty/) to set up its `DUTY` value. In its turn, `Ton` will define light “on” time (in seconds) and `Toff` defines off-time. One hour is 3600 seconds 😉 If you still have questions, feel free to ask. ---
**Author:** ![alessandrogiannini](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.xod.io/alessandrogiannini/32/931_2.png) [@alessandrogiannini](https://forum.xod.io/u/alessandrogiannini)\ **Post date:** [January 2, 2018, 6:10pm UTC](https://forum.xod.io/t/timer-for-lights/348/3 "2018-01-02T18:10:13Z")
Thank you for the reply. Yes I have some other questions: - Because I am using a lot of digital pins I don’t have enough space for a classic lcd so I used a i2c module, if I put the wrong addr is it going to damage the i2c module? - I want to make a menu in the lcd that allows (when a button is pressed) to switch between views with different data, how do I do that? - If I use a 16x3 module how can I have access to the 3rd line? Thank you so much for helping me and sorry for all of these questions but I know only the basics of electronics. ---
**Author:** ![nkrkv](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.xod.io/nkrkv/32/8_2.png) [@nkrkv](https://forum.xod.io/u/nkrkv)\ **Post date:** [January 3, 2018, 1:45pm UTC](https://forum.xod.io/t/timer-for-lights/348/4 "2018-01-03T13:45:34Z")
> [@alessandrogiannini](#): > > if I put the wrong addr is it going to damage the i2c module? No, absolutely not. The worst thing going to happen is you will not see the text. > [@alessandrogiannini](#): > > I want to make a menu in the lcd that allows (when a button is pressed) to switch between views with different data, how do I do that? One possible way is to have [`if-else-string`](https://xod.io/libs/xod/core/if-else-string/) nodes right before the LCD node. Another solution is to have multiple LCD nodes that refer to the same display, but have [`gate-string`](https://xod.io/libs/xod/core/gate-string/) nodes before each one and keep only a single gate pair open. > [@alessandrogiannini](#): > > If I use a 16x3 module how can I have access to the 3rd line? 😮 Do they exist? Thats not directly possible with already existing nodes, but you can copy implementation of the 16×2 and make small adjustments (add an input and few lines in C++) to make your own `text-lcd-16x3-i2c` node. ---
**Author:** ![dox](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.xod.io/dox/32/424_2.png) [@dox](https://forum.xod.io/u/dox)\ **Post date:** [January 3, 2018, 4:49pm UTC](https://forum.xod.io/t/timer-for-lights/348/5 "2018-01-03T16:49:22Z")
@alessandrogiannini: You can try this: Add library --\> dox/lcd-i2c I found a 16x3 Display with SPLC780D Controller. This could be compatible to standard HD44780 controller. No guarantee that it will work. I am not a programmer. This is just a modification of the existing nodes. ---
**Author:** ![alessandrogiannini](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.xod.io/alessandrogiannini/32/931_2.png) [@alessandrogiannini](https://forum.xod.io/u/alessandrogiannini)\ **Post date:** [January 3, 2018, 6:28pm UTC](https://forum.xod.io/t/timer-for-lights/348/6 "2018-01-03T18:28:59Z")
Thank you for the detailed answers. Is it possible to have access to the serial monitor? ---
**Author:** ![nkrkv](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.xod.io/nkrkv/32/8_2.png) [@nkrkv](https://forum.xod.io/u/nkrkv)\ **Post date:** [January 3, 2018, 10:41pm UTC](https://forum.xod.io/t/timer-for-lights/348/7 "2018-01-03T22:41:17Z")
> [@alessandrogiannini](#): > > Is it possible to have access to the serial monitor? Sure. Use `console-log` node and upload with “Debug after upload” checkmark set. ---
**Author:** ![alessandrogiannini](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.xod.io/alessandrogiannini/32/931_2.png) [@alessandrogiannini](https://forum.xod.io/u/alessandrogiannini)\ **Post date:** [January 3, 2018, 11:05pm UTC](https://forum.xod.io/t/timer-for-lights/348/8 "2018-01-03T23:05:14Z")
How do I convert a analog signal in a string? ---
**Author:** ![nkrkv](https://yyz1.discourse-cdn.com/flex027/user_avatar/forum.xod.io/nkrkv/32/8_2.png) [@nkrkv](https://forum.xod.io/u/nkrkv)\ **Post date:** [January 4, 2018, 10:20pm UTC](https://forum.xod.io/t/timer-for-lights/348/9 "2018-01-04T22:20:49Z")
Simply link your number output (from an `analog-input`) to a string input (like `L1` on `text-lcd` or `if-else-string`) and magick will happen. If you’re not satisfied with the magick, use the [`format-number`](https://xod.io/libs/xod/core/format-number/) node. ---
**Author:** ![coradias](https://avatars.discourse-cdn.com/v4/letter/c/b4bc9f/32.png) [@coradias](https://forum.xod.io/u/coradias)\ **Post date:** [February 2, 2018, 12:52pm UTC](https://forum.xod.io/t/timer-for-lights/348/10 "2018-02-02T12:52:59Z")
Hi…if you have metal halide lights a cheap timer will fail at some point as the ballast draws a lot of current for a split second at start up. a heavy duty timer may be a consideration. Otherwise go for a cheap one. [heavy copper pcb](https://www.7pcb.com/blog/heavy-copper-pcb.php)