Backyard Aquaponics
A place to discuss aquaponics

Look at figure 9 on that datasheet.
That is how I would do it.



Where they have the motor is where you would put your coil in the air pump.
For your application:
Logic supply voltage is 5V
Supply voltage is 12V
The C and D inputs would be your control lines from the PIC, no need to use PWM imo.
1 - Take C high for n milliseconds.
2 - Take C low
3 - Short delay
4 - Take D high for n milliseconds
5 - Take D low
6 - Short delay
7 - goto 1

The ground pins are arranged like that so you can put a heat sink over the top of the chip or a big ground plane on the PCB.

As DuiNui said, for heatsinking. Many chips also have many grounds and power pins because they need more power than one pic can provide. Also the chip might need lots of power in 2 different areas of the chip and instead of putting the wires inside they might just add extra power pins. High frequency processors might have 10-20 power pins, some might be 5v some 3v and some 2.5 v. Each pin needs a capacitor within a mm or 2 of the pin as well,... I digress..

5v and 3.3 v are almost always the voltage of logic. This powers all the internal circuitry used to control the output.
The Supply Voltage pin is so you can have a different voltage to drive the motor. This chip is kind of a whole circuit board inside one block.

5v...................................12v
|.....................................|
Logic ->controls -> motor switching

Think of it like there are 2 totally seperate parts inside the chip (which there kinda is)

PS dont forget the diodes. Any old power diodes will be fine. Schottkys will use less power but no biggy...

No front end made for it yet, so input is strictly 0-3.3V.

Oh Ao.
I made this today too.
I think you might recognise the PCB.
Thanks again for sending those, I made this and wrote the software in about an hour, thanks to your PCB

It's good to know that my PCB can help, dui.

You seem to be very active, make thing all the time.
I loose my enthusiasm when getting older.

btw
so your scope can mesure volt less than 5v right?

I do too, but only for some things


Right now it measures 0-3.3V (PIC24F are 3.6V absolute max)

I will add an Op-Amp front end and some sort of resistor network, possibly a programmable one.

Hmmm... I like Opamp, can do many function, analog IC.

The secret is hanging out with young people.



I once asked my two year old friend Sarah where wind comes from.

She told me the trees make it by waving from side to side.

Obvious really when you think about it.

I like that., BW.

Interestingly, one day when I was looking after my grandmother, I asked her the same question. She made an "Oh" sound like the first syllable in the word "Otter" for around an hour and a half.

Because I erroneously thought I was onto something, I asked my mum's man the same question, and he gestured towards the north west.

My own answer involved complicated, abstract concepts involving butterflies.

Clearly, two year old girls know way more than everyone else.

The best part was how much time Sarah put aside to explain it to me.

Really important, the putting aside time to explain stuff.

That's another worthwhile lesson Sarah did really well.

Sarah's was the first nappy I ever changed.

Baby [I cant believe the forum software didn't edit this] really stinks.

When go to the sea beach my daughter eager to swim and play. While adults worried about safety, strong sun light, cleaning.
The adults sit on the beach, eat, talk, sleep... Sometime their foot didn't touch the sea water.

I remember when I was young sea water is the must.

Buddha teach that everything has 3 common characteristic.
1 Uncertainty, nothing is sure.
2 Everything must be changed.
3 No thing really exist. Everything composed of something else.(What is your car? engine? wheel?...)

In this case myself(a boy in the past) and myself(a man now) is changed and is not the same thing.

Hmm... that concerning 12v topic