How to Make a Low Tech Timer Switch.





Introduction: How to Make a Low Tech Timer Switch.

This is an Instructable to make a very low tech timer switch. mine goes off once every 12 hours for about 3 minutes. I made this because i not really that good with electronics but still wanted a cheap timer. This is just the prototype and i hope to make a much more permanent one when i have the time, the plan is to use it to automatically turn on my solar powered irrigation system in my greenhouse. That might be my next instructable.
Oh and by the way, this is my first instructable so any comments would be welcome.

Step 1: Tools and Parts.

The tools and parts I used where what I had lying around. This made this project free and also green as i recycled some parts

Tools -
soldering iron
soldering iron holder
electricians tape
solder sucky thing (don't know what its called)
third hand
multi-meter (although i don't actually think i used it but thought i might so took a photo of it)

Parts -
Paddle lever switch or something similar
clock movement
c.d. or d.v.d
battery holder
breadboard connecters
motor or LED

Step 2: Remove the Switch From Circuit

The idea of this timer is for the hour hand of the clock to hit the switch as it passes and completes the circuit. The switch i used was from an old cd player. This meant i had to take it off the circuit board. To do this i heated up the solder with an soldering iron and sucked it away with the sucking tool. The the switch would just fall out. After i got the switch out i then sanded a tiny aounf off one of the corners.

Step 3: Lining Up the Switch and the Clock.

Glue the c.d to the clock movement. I had to put a rubber washer in between them to make the hands at the same height as the switch so this might be something to check before gluing. Then stick the switch inline with the hour hand. Alliteratively if you want the timer to go off every minute then put the switch inline with the second hand, or every hour put it inline with the minute hand. On the picture you can see that i have put the sanded corner of the switch near to the clock hand to make it press it easier. At first i only used tape to secure the switch as i wanted to make sure the it all worked.

Step 4: Make a Test Circuit

Make a very simple circuit. I used a small motor but an LED would just work as good. Any electronic device would work so long as its easy to see when the circuit is completed. This is just to test the switch to see how long the circuit is completed. Mine is about 3 minutes but different switches and clock movements may have different times. On the picture below you can see the 2 wires that are to be connected to the switch on the cd.

Step 5: Solder the Wires and Test.

Solder the wires to the switch and then set the hand just before the switch. Hopefully in the next few minutes the clock hand should turn on the circuit. If it does not then the position of the switch may just need to be adjusted. If it all works then just glue the switch into place and then find a use for this timer.
This is probably not the best way of making a timer as i'm sure a pic chip could do all this and take up a fraction of the size. But for a really cheap easy timer i found this to be just fine. If you do use this idea of a timer i would love to hear what you used it for or any improvements you may have.
Thanks for reading. :)



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    38 Discussions

    your timer reminded me of the alarming paddle clock That I constructed when I was a boy. Nice

    if you want a more permanent and compact switch go ahead with some electric components like a RC circuit in which you will have to select value of resistance and capacitance according to what time gap you want, to make a nice time switch which will switch on and off after fixed period of time(same for on and off delay)

    Nobody has yet mentioned that mechanical clocks like this are not so common anymore. You can still buy battery operated ones at hobby stores for making your own clock, but you never see any but digital at goodwill or yardsales.

    I'm just wondering people. Would the paddle lever of the paddle lever switch not prevent the hour hand from continuing its motion.

    whats a "Paddle level switch"?

    Thank you for posting this. It is very well done. We will be looking for many fine Instructables from you as time goes by!

    By the way, before the advent of digital watches with alarms, what you describe is the way many bombmakers set off their explosive devices. An even less sophisticated procedure used during World War II in a failed attempt to assassinate Adolph Hitler was to break the neck on a vial of acid so that it dripped onto a steel wire. The time delay was in the time needed for the acid to eat through the wire. When that happened, a spring held in tension by the wire released a detonating mechanism. I read about it in Shirer's The Rise and Fall of the Third Reich. When this bomb failed, those who had placed it had to retrieve it unnoticed, lest their plot be discovered. They did.

    12 replies

    wow i have allway though of doing some hing like this but you should try and find a hot gule gun it will look better and last longer and where do you live 'cuz you have a 240v soldering iron...

    "and where do you live 'cuz you have a 240v soldering iron..." My guess would be any other country with sense in electrical engineering.

    usa...i want to move out maybe to the brits they have free health care yea a about what you said the 240v @50hz i heard it is alot better i think the usa or 'boma dont care i did like this though

    cool i like the free health care that cuba and most other places havewhen you think about it cuba is a very firendly place

    Preface: I'm a socialist in the proper sense of the word. Cuba is not a good place in terms of authoritarianism which regrettably seems to go hand in hand with communism on a state-wide scale. Political prisoners and such what. What they've done developing permaculture and health care, because of the US blockade blocking many medicines and things like fertilizer etc however is pretty admirable.

    Or you could come to Australia, we allways help newbie around the place - except the chaser.

    free public education exists in the US too (but it gats paid by taxes soooooo I guess it isn't really free. :)

    I live in the U.K. The soldering iron used to be my dad's so its quite old, but still works so i'm happy.

    oh i was wondering why it was so big i have never seen one like it