Backyard Aquaponics
A place to discuss aquaponics

You could use an interval timer micro or other wise to trigger 2 pulse generators. If you have one detect a negative edge and one detecting a positive edge coming from the interval timer they could drive a h bridge.

I could also adjust the program on the interval timer I suggested to do it. I would drop the time adjustment down to 65 min and use 2 ports to drive the h bridge just pulse them instead of keeping them on. So the relay would pulse to open then wait the open period and pulse to close then wait the close period etc. If we went to a larger pic we could make it selectable between pulsed or continuous operation, it would not cost much more.

This is the type of ideas I was suggesting for developing a general purpose unit. So others please feel free to chip in with desired features.

An over-riding open closed switch for each growbed would be nice.
Its a pain having to cycle timers when you are doing testing or want to shut a growbed off for repairs, maintenance etc.
John

Now my ignorance shows through even more. I need to look up pulse generators and how to have them detect the negative and positive edges. And what is an h bridge?


Yes, these ideas sound good to me.


definitely shaping up with some good ideas here guys. I wish I knew just a little more about this kind of electronics. I'm mainly good at the signal flow or as I like to call it, the "plumbing" side of electronics (basically finding the bad cables and replacing them before the show starts.)

Anyone know how much shipping small electronics like this would be between Au and USA?

I just copied this over from the Sequential thread so all the information is here



You can't use these actuators to actually hold the valve open or closed - design the valve so the water flow or a detent of some sort holds the open or closed position and the actuator just shifts between the two positions - click the door lock on your car and you will get the idea. The lock flicks over from open to closed mechanically, the actuator just kicks it over the middle hump.

John

I think many people are interested in one timer controlling the pump, for those like myself that are using sequenced growbeds because the system has an overflow you can just manually open or close the valves.

or unplug the cable to the actuator

Well I'm finally done with this past week's gig and have some time to look at the electronics bits I ordered.

Arg!!!!!
Well the instructions without the diagrams are pretty pointless. I got parts but the instructions only tell which pins to pick for time but not what other pins need to be plugged to what to make it all operate!

I did get a little timer kit that is bassed on a 555 chip and I was able to get that to work but it only does on cycles from .5 to 5 seconds and off times from 2-60 seconds so that doesn't really help me much for a timer that needs longer periods.

Is the offer to program chips still open? How would that work with shipping from AU to USA? You would still need to diagram how to wire up the rest of the circuit to make the actuator controller.

I've been asking questions on some electronics forums but their general answer to newbies is to tell you to go google it. I'm having trouble even getting them to recommend what search phrases I should be using to find what I'm searching for.

Hi TC,

I've been developing a programmable on/off timer that should do the trick. It has a USB port so you can plug it into a PC and send it a couple of commands to set the on/off timing. The only problem is that it's a bit expensive for the low-powered relay. The entire thing is run on 3 AA batteries so I had to be careful with the power consumption. I'm hoping to keep the parts for the prototype unit below $50. I should be done with it in the next month....but my real job keeps getting in the way!

i found this guy on ebay for 15 bucks and was thinking it would work well enough? keep in mind its for a small pump and for less than 15 amps. anyone have any luck with a small timer similar to this?

It only gives you 20 on/offs - quite often not fine enough for us.

I want a timer to run for say 10 minutes, have 1 minute off, then run for 10 minutes again. This is to run the indexing valves like what Rupe is building eventuallly.

As I'm doing this for interest and the greater good, more than for my own use, I've been getting a little slack.
But here is the latest design


and also a layout for standard veroboard.



Blue tracks are the existing tracks on veroboard that need to be cut,
red tracks are wire links on the top side of the board.



This is a list of parts and prices (shipping needs to be added).

Now I just have to get around to puttin gin an order so I can make sure this actually works.

So Kuda, what will this timer be able to do? Can it drive a 240v relay?

OB, there is a relay on the schematic, far right hand swith thingi...
there is also a 5V coil 5A @ 277V relay in the parts list.
This will do 5A at 240, yes...

5A @ 240VAC is 1200VA or about 1.2kW
I think that covers all the pumps we'll ever want to use.
If you want it for a 12V pump, it'll work for that too, but still only 5A so about 60W Max.