DIY adjustable timers - electronics guru required

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NS775

Member

• Dec 2, 2009

• #1

Am i missing something here? Why are companies charging $75+ for sub 15 min timers??? Couldn't you construct an adjustable timer for about $15? for example...

Using a 125v relay such as this...
http://www.radioshack.com/product/index.jsp?productId=2049721

and a basic 555 timer circuit similar to this...
[Link]
http://www.zen22142.zen.co.uk/Circuits/Timing/5_30timer.gif

would it not be fairly straightforward to build a simple timer for something like an aeroponic pump timer?

 

W

watson540

Member

• Dec 2, 2009

• #2

or you could be like me and go to walmart and buy one that works in one minute increments, has 9 different time settings you can use (Though I dunno why), two 3 prong outlets, and a 15amp load (I think), for about 16-19$USD..seriously, who pays over 20 bucks for a difital timer?!

mine even has a li-ion backup battery in it..it's a "brinks" brand..pretty sure its just a little microcontroller in there(has random funtion as well)..but expensive they are not

 

supermanlives

Active member

Veteran

• Dec 2, 2009

• #3

i paid over a hundred for mine.

 

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watson540

Member

• Dec 2, 2009

• #4

WOW! a hundred eh??

Mine works fine for me, but in my case everything is on the same schedule. What I would love to do is be able to control both individual outlets on mine..individually

I mean it's cool that you can program like 9 times in, it does me little good (maybe for a flood pump it would be good), but it would be great if those 9 times could be split exclusively between the two outlets..

On the original subject, I would guess you could for sure build on on the cheap..I have experience in electronics but its been a while, and never used those 555 timers though I do see them to be quite common

 

grow1620

Member

• Dec 2, 2009

• #5

I would love to see a diy type thing to make a recycle timer....the 1 minute on 5 off type..or adjustable.

 

M

Me2

Member

• Dec 3, 2009

• #6

grow1620
This one will fit the bill for most low pressure aero applications.
http://www.icmag.com/ic/showthread.php?t=131719&highlight=cycle+timer

NS755
I have a couple of timers that use series resistors on 12 way rotary switches. Its a good design as the settings are more repeatable than using a pot which can be hit and miss finding the same timing twice