Sonsivri
 
*
Welcome, Guest. Please login or register.
Did you miss your activation email?
June 21, 2018, 01:45:30 01:45


Login with username, password and session length


Pages: [1]
Print
Author Topic: Cheap 1 hour timer for 220v suggestions  (Read 909 times)
0 Members and 1 Guest are viewing this topic.
snowman
Junior Member
**
Offline Offline

Posts: 70

Thank You
-Given: 147
-Receive: 50


« on: June 03, 2018, 06:26:32 06:26 »

Hi folks,

I need a timer circuit to light a 220v small bulb for 15 minutes on every 1 hour. duration does not need to be accurate. instead of 15 minutes it can be 20 etc.

I looked into 555 solutions, arduino solutions, 4060 solutions. Looks like 220v-12v or 220v-5v adapter is more expensive than circuit itself.

I had problem with 555 solution because every online 555 calculator calculates frequency and period from given capacitor and resistance values, but I need it backwards. a calculator that gives resistor and capacitor values from given frequency. Also they are not clear about on-off times. If I needed square ware that would be fine but that's no the case.

I need ideas about power supply of this device. It should be small and should not generate heat. Needed current is very small, relay is small one like arduino relay modules. There are transformerless power supply schematics online but they don't mention about heat (this device will be in closed box forever)

Basically I could not decide.

Can anyone point me a direction with ideas please.

best.
Logged
Sideshow Bob
Cracking Team
Hero Member
****
Offline Offline

Posts: 584

Thank You
-Given: 195
-Receive: 619



« Reply #1 on: June 03, 2018, 07:16:54 07:16 »

This is not meant to be disrespectful. But this is in the same alley as building your own heatsink using scrap metal plates in order to save money. Programable digital timers that you put into the mains socket are dirt cheap and they often do have a battery for backup. Non digital like this one as an example https://www.ebay.com/itm/Digital-Electronic-EU-US-UK-AU-Plug-in-Programmable-24-Hour-Timer-Switch-Socket/322553113078 is even cheaper. Look for them on EBAY, Alibaba Express etc
Logged

I really am ruggedly handsome, aren't I?
CocaCola
Senior Member
****
Offline Offline

Posts: 452

Thank You
-Given: 129
-Receive: 209



« Reply #2 on: June 03, 2018, 12:58:07 12:58 »

As Sideshow said, don't re-invent the wheel unless you need to...

Not a product endorsement, just another example of how cheap these things can be sourced vs built...

https://www.ebay.com/itm/Cycle-Delay-Timing-Timer-Relay-Switch-Turn-ON-OFF-Module-AC-110V-120V-220V-230V/263430643827
Logged
Wizpic
Global Moderator
Hero Member
*****
Offline Offline

Posts: 1048

Thank You
-Given: 273
-Receive: 369



« Reply #3 on: June 03, 2018, 03:00:42 15:00 »

I would use and Arduino mini a 5v relay module all cheap enough from e-bay and one of these for for the power supply 240v to 5v dc all in one no need for rectifier
[urlhttps://uk.rs-online.com/web/p/pcb-transformers/8695025/][/url]

I did a fish tank pump controller the same way it ran left pump for 5 minutes and then the right wave pump plus added a button to turn them off for 15 minutes while feeding work very well
Logged

When you think, "I can't do anymore. I need a break," that is the time to challenge yourself to keep going another five minutes. Those who persevere for even an extra five minutes will win in life..
snowman
Junior Member
**
Offline Offline

Posts: 70

Thank You
-Given: 147
-Receive: 50


« Reply #4 on: June 03, 2018, 03:20:41 15:20 »

Hi,
To answer Slideshow Bob, I have one of these. Their interval not suits my needs. Also I have one of electronic ones. they cannot turn on and off 1 hour/15 minutes intervals. Mechanical ones work half an hour/half an hour.

To Wizpic; the product you offer is 11 pounds. Not acceptable for me. Aliexpress has cheaper ones but still expensive comparing to timer device itself.

CocaCola got the point. the device he offers is about 5 dollars. I believe including power supply. That was what I needed. I could not find that kind of product with my research, maybe because ebay is not usable in the damn country I live.

thanks.

Logged
Sideshow Bob
Cracking Team
Hero Member
****
Offline Offline

Posts: 584

Thank You
-Given: 195
-Receive: 619



« Reply #5 on: June 04, 2018, 05:14:39 05:14 »

Hi,
To answer Slideshow Bob, I have one of these. Their interval not suits my needs. Also I have one of electronic ones. they cannot turn on and off 1 hour/15 minutes intervals. Mechanical ones work half an hour/half an hour.
Actually those digital week timers are just made for such a task. Once I did a setup very simlar to your project. I had to run a pump regulary  monday to friday but it could not run dry. As that would damage the pump. So I set a digital week timer run for 10 minutes every hour monday to friday. For that job I found a chap timer with 96 programable on/off. More than enough to do the task 
Logged

I really am ruggedly handsome, aren't I?
Parmin
Hero Member
*****
Offline Offline

Posts: 559

Thank You
-Given: 378
-Receive: 130


Very Wise (and grouchy) Old Man


« Reply #6 on: June 04, 2018, 06:04:11 18:04 »

If you have to make one yourself, I suggest to see Microchip's transformerless power supply and design with a PIC - you will end up with a lot less components and quite cheap system.
OTOH, like most above, I would suggest to use commercially available system.
Logged

If I have said something that offends you, please let me know, so I can say it again later.
Wizpic
Global Moderator
Hero Member
*****
Offline Offline

Posts: 1048

Thank You
-Given: 273
-Receive: 369



« Reply #7 on: June 05, 2018, 12:14:10 00:14 »

Cheap and custom designs do not go together  Grin, If I was you I would stick with the commercially available system  Smiley. You could use  transformerless power supply but then safety come into mind, I looked down this route but then decided against for that reason, I value my house  Shocked
Logged

When you think, "I can't do anymore. I need a break," that is the time to challenge yourself to keep going another five minutes. Those who persevere for even an extra five minutes will win in life..
Sideshow Bob
Cracking Team
Hero Member
****
Offline Offline

Posts: 584

Thank You
-Given: 195
-Receive: 619



« Reply #8 on: June 05, 2018, 01:49:21 01:49 »

If you have to make one yourself, I suggest to see Microchip's transformerless power supply and design with a PIC - you will end up with a lot less components and quite cheap system.
OTOH, like most above, I would suggest to use commercially available system.
If on a budget, I would have asked around if sombody could donate an old cellphone charger. As this solution is more safe for the hobbyist. At least if a an orginal charger is used. The aftermarked ones should in theory also be safe. But many of those are cheap products from China, not complying with regulations even if they are labled as such
« Last Edit: June 05, 2018, 03:29:40 03:29 by Sideshow Bob » Logged

I really am ruggedly handsome, aren't I?
snowman
Junior Member
**
Offline Offline

Posts: 70

Thank You
-Given: 147
-Receive: 50


« Reply #9 on: June 05, 2018, 10:25:03 10:25 »

As I said before I have mechanical programmable timer plug. My intention was remove the internals and insert a power supply, pic, 555 or arduino nano or maybe esp8266 and a small 5v relay. This device have great compact 2 way plug. I also have a koogeek plug and case is so small and compact that I wonder how they fit all electronics there. Power supply, mcu, bluetooth, wifi, relay, leds... But its too far expensive for disassembling.
Logged
ero
Newbie
*
Offline Offline

Posts: 27

Thank You
-Given: 1
-Receive: 18


« Reply #10 on: June 06, 2018, 04:33:15 04:33 »

The cheapest system is to use one microcontroller with a relay powered by simple (unisolated) power supply.
It is very easy to make this but the main problem is to microcontroller. You need to program it by using a programmer.

Project files are enclosed.
When yo give the power to the system it is counting first one hour. Later drive the relay for 15 min than close the relay and counting again one hour and continuing so on.

If you are not able to work with un isolated circuit do not make this project it canbe dangerous. If you want a safety system you should use 3w / 0-6V transformer for power supply

Ete

Logged
Pages: [1]
Print
Jump to:  


DISCLAIMER
WE DONT HOST ANY ILLEGAL FILES ON THE SERVER
USE CONTACT US TO REPORT ILLEGAL FILES
ADMINISTRATORS CANNOT BE HELD RESPONSIBLE FOR USERS POSTS AND LINKS

... Copyright 2003-2999 Sonsivri.to ...
Powered by SMF 1.1.18 | SMF © 2006-2009, Simple Machines LLC | HarzeM Dilber MC