Unlimited Dosing pumps using PWM

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JasonJohn
Posts: 3
Joined: Fri May 24, 2013 4:09 am

Unlimited Dosing pumps using PWM

Post by JasonJohn »

Hi all.

I'm new here but I have my RA+ for 1-1/2 year now and I was using it on a fresh water tank for all the basic stuff.
The setup was simple and straight forward, only ATO with float switches, heating, fans to cool down and lights on/off.
But since a week i'm moving to a reeftank and bought a couple of extras for my beloved RA+
RF module + wifi + extra temp probe + expansion hub.
And I also have 6 peristaltic pumps, 12V motor driven and would like to use them but not with the relay box as , for me, it seems to be unproductive and a waste to use these AC main relays for dosing pumps.


So as I'm using a Maxspect P with it's controler I dont use the PWM from the RA+.
The idea is to have a single cheap ATMEL uC associated with each dosing pump reading the PWM output of the RA+. So the PWM exit will be like a bus line and all the dosing pumps will be connected to it and reading the duty cycle. Having a specifc dutycycle for start / stop assigned to each dosing pump. Simple.

I am using the free version of Bascom AVR for programming some Attiny XX chips, and having a chip for each pump eliminates the need of complicated timers and IRQ/watchdogs and can even leave the real dosing out of the RA+ as it can simply send the start signal and the pumps will do XXX numbers of turns (using optical sensor like a phototransisor / light gate system) or time based, or even using a simple potmeter to define the dosing time/counts and add a push button to start manually a dosing cycle.

But I'm not confident with the RA+ coding........ :roll:

So what do you guru guys think of it ?
rimai
Posts: 12881
Joined: Fri Mar 18, 2011 6:47 pm

Re: Unlimited Dosing pumps using PWM

Post by rimai »

Wait until next week :)
I'll have a doing pump module released...
It will have 8x 12VDC ports for dosing pumps and you can control them individually just like any port of the relay box.
In fact it will use the same backend and it will act as if it were an expansion relay box, except it controls 12VDC ports instead of AC power ports.
I just got the shipping notice and it should be here end of next week.
Roberto.
JasonJohn
Posts: 3
Joined: Fri May 24, 2013 4:09 am

Re: Unlimited Dosing pumps using PWM

Post by JasonJohn »

Keep one for me then !!!!

That is good to have as we dont always need an AC main switch but a low voltage.
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