# I just cant get enough of autodosers



## VadimShevchuk (Sep 19, 2009)

that is a great idea. You should do a write up on how to make one. We have one of those automatic air fresheners laying around too!


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## Jaggedfury (Sep 11, 2010)

Nice! I actually have 6 of those automatic air wicks all around the house. Cool little DIY you got there.roud:

I noticed that, once your battery is low, the motor will become weak which will still depress the air scent nozzle, but enough to just barely spray any out. I threw in 2 rechargeable 2500mAH batteries, and what a big difference in the power of the motor depressing the nozzle. Its shoots 4 feet long mist.

Would that be a problem as the battery gets low? I'm assuming you did run it on the standard battery setup.


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## majstor76 (Jun 11, 2010)

Jaggedfury said:


> Nice! I actually have 6 of those automatic air wicks all around the house. Cool little DIY you got there.roud:
> 
> I noticed that, once your battery is low, the motor will become weak which will still depress the air scent nozzle, but enough to just barely spray any out. I threw in 2 rechargeable 2500mAH batteries, and what a big difference in the power of the motor depressing the nozzle. Its shoots 4 feet long mist.
> 
> Would that be a problem as the battery gets low? I'm assuming you did run it on the standard battery setup.


Yes, i did run it on pair of 2300 mAh Duracell nimh batteries. Dont know how long would last, didnt manage to test it but i was thinking of connecting spray thing to some 2.5V DC dc power adapter or something (but didnt have one so low at hand). Tried some cellular chargers, led is blinking but motor wont work


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## majstor76 (Jun 11, 2010)

Ok, here is short guide how to do it.

First we need to shave off excess plastic from head of pump so wed have to cut less on device. 
Next, since output of head is wide and usual air hose wont fit i found some bigger hose which connected output of pump with normal air hose (blue) which goes into aquarium. Some silicon is used to plug eventual holes and you can burn hose a bit for better fit (rhyme!).












Now see if head of pump fits in hole in device. Probaby it wont, so take a soldering gun and make it wider. Not TOO wide, it must not have much left-right movement.











Cut bottom of bottle so it can fit in device. Carefull not to cut too much or bottle will be too low and moving part wont push head. Cut little by little till it fits. After that connect hose with pump intake , that hose goes into fert container










Take some tape or piece of rubber and wrap it around bottle in device so it doesnt flip out when moving part presses head. Test device and see how much is in one squirt, mine was about 1ml. 
If 40ml a day is too much for you (which is lowest i got) , you can maybe try to lower bottle so moving part wont fully press head and there will be less liquid in one pump action. 
Alternatively, when buying bottle , look for one that have thinest piston in pump (spring is inside). The thinner piston, the less should be in one squirt


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## DarkCobra (Jun 22, 2004)

That is an awesome idea!



majstor76 said:


> Yes, i did run it on pair of 2300 mAh Duracell nimh batteries. Dont know how long would last, didnt manage to test it but i was thinking of connecting spray thing to some 2.5V DC dc power adapter or something (but didnt have one so low at hand). Tried some cellular chargers, led is blinking but motor wont work


Yep, cell charger current is too low.

I doubt the Airwick has any voltage regulation built-in. But 3.3V is a common max voltage for microcontrollers, so it can _probably_ handle that voltage without a problem; and that opens up a few possibilities. Plus you'd get more motor torque too.


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## Azrie (Jan 5, 2011)

majstor76 said:


> Test device and see how much is in one squirt, mine was about 1ml.
> If 40ml a day is too much for you (which is lowest i got) , you can maybe try to lower bottle so moving part wont fully press head and there will be less liquid in one pump action.
> Alternatively, when buying bottle , look for one that have thinest piston in pump (spring is inside). The thinner piston, the less should be in one squirt


Instead of modifying the doser you could also just dilute your fert mixture. Twice as much water would allow you to keep the 40ml per day but only put in 20ml worth of ferts. Use whatever calculation you need to get the right amount without the hassle of fiddling around with the mechanism. 

By the way this sounds great and I'm in the process of whipping up one myself. Great idea!


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## majstor76 (Jun 11, 2010)

Azrie said:


> Instead of modifying the doser you could also just dilute your fert mixture. Twice as much water would allow you to keep the 40ml per day but only put in 20ml worth of ferts. Use whatever calculation you need to get the right amount without the hassle of fiddling around with the mechanism.


Yea, im doing that with my two peristaltics which dose ppspro. I wrote a calculator which calculates dosing if we give volume of aqaurium, volume of fert and amount of dosing. I know mix for mine aquarium but people come and beg 



Azrie said:


> By the way this sounds great and I'm in the process of whipping up one myself. Great idea!


Thanks all, this is just a something in return to community


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## majstor76 (Jun 11, 2010)

This is somewhat updated version, with bits here and there


Melt a hole in body of bottle and pull trough it hose for fert container












Melt edge of plastic bottle sits on and make a rim to make it harder for bottle to slip off...











... and close the hatch










I have put full batteries on 9 min setting to see how much it can last.

Now all we need is some DC power adapter or something. Can anyone handle this, im bad at electronics?


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## majstor76 (Jun 11, 2010)

DarkCobra said:


> That is an awesome idea!
> 
> Yep, cell charger current is too low.
> 
> I doubt the Airwick has any voltage regulation built-in. But 3.3V is a common max voltage for microcontrollers, so it can _probably_ handle that voltage without a problem; and that opens up a few possibilities. Plus you'd get more motor torque too.


Yes it can handle 6V, the cellular charger i tried is 5.6V / 380mA . But, like i said motor wont work, it makes some faint buzz but it wont move


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## majstor76 (Jun 11, 2010)

I did a 24h test on 9 minutes setting and result is 170ml divided on 160 squirts, that means that one squirt is about 1,0625 ml with this particular bottle.


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## DarkCobra (Jun 22, 2004)

majstor76 said:


> Yes it can handle 6V, the cellular charger i tried is 5.6V / 380mA . But, like i said motor wont work, it makes some faint buzz but it wont move


Odd, I wouldn't have expected that.

But also good, because 5V regulated power supplies with ratings up 1A and higher are fairly common.


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## majstor76 (Jun 11, 2010)

DarkCobra said:


> Odd, I wouldn't have expected that.
> 
> But also good, because 5V regulated power supplies with ratings up 1A and higher are fairly common.


Whats the difference between regulated and unregulated power supply? And what is switching power supply?


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## DarkCobra (Jun 22, 2004)

*Unregulated power supply*

The most frequently encountered species is the "wall wart". Here we see one grazing in its natural habitat:










This contains a transformer to convert 120VAC to lower voltage AC, a bridge rectifier to convert that to massively fluctuating DC, and a capacitor to smooth out and average the DC to some usable value.

The actual voltage out depends on the load it's powering. Around it's intended load, it will be around the voltage marked on the case, more or less. Load it too much and the voltage drops, load it very lightly (or not at all) and the voltage can go 30% or more _higher_ than its rated output.

Consequently, equipment powered by this often has a regulator, which steps the power from the "wall wart" down to an even lower, but much more constant voltage. See below.

*Regulated Power Supply*

There are two main species: linear and switching.

*Linear power supplies* reduce a higher and possibly fluctuating DC voltage to a lower and constant DC voltage. This is what I mentioned above. It functions by turning all the excess voltage to heat, which must be dissipated, and isn't very efficient - especially if the voltage differential is large. But they can be very simple and cheap, even consisting of just a single electronic component; like this one, which is about 0.3" wide:










*Switching power supplies* are a much more complicated beast, with many subspecies. Depending on design, they may be powered from AC or DC.

From a non-electronics standpoint, think of trying to maintain a constant speed on a bicycle. When you go too slow, you pedal; if you reach or exceed your desired speed, you stop pedaling and flywheel.

The switching power supply performs a similar feat _tens of thousands_ of times a second by closing an electronic switch between the input and output to "pedal" and raise the output voltage, or closing it and letting the "flywheel" run to let the output voltage drop.

Switching power supplies can be very efficient, especially compared to linear ones. They produce little heat and waste little electricity.

They're everywhere. There's a big fancy one powering your computer. Many consumer electronic devices use external ones, and they typically look like this:










Though some of the newer ones have advanced in miniaturization to the point where they resemble unregulated wall warts.

That's the basics. Let me know if you need more specific details on anything.


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## majstor76 (Jun 11, 2010)

DarkCobra said:


> Though some of the newer ones have advanced in miniaturization to the point where they resemble unregulated wall warts.
> 
> That's the basics. Let me know if you need more specific details on anything.


Tnx man roud:, now im off to do some educated buy :biggrin:


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## DarkCobra (Jun 22, 2004)

Majstor76, congratulations! Your project has been featured on Hack A Day:

http://hackaday.com/2011/01/21/fertilizing-a-planted-aquarium-using-air-freshener-hardware/


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## majstor76 (Jun 11, 2010)

DarkCobra said:


> Majstor76, congratulations! Your project has been featured on Hack A Day:
> 
> http://hackaday.com/2011/01/21/fertilizing-a-planted-aquarium-using-air-freshener-hardware/


Yes! My genius has finnaly been recognised


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## gregjonesonline (Jan 22, 2011)

I saw your auto-doser on hackaday, watched the video on youtube, read your thread here, and decided this was exactly the type of project i wanted to do next, so thanks for the awesome idea!!!

I went to Walmart and found the AirWick Freshmatic Ultra: http://www.airwick.us/access/html/products/product_A000230.html

I also picked up a slim push pump soap, and probably the most exciting part of all, I found a Universal AC Adapter which has a voltage selector to emulate a wide range of batteries, from 3 - 12 volts DC / 600mA. I haven't had a chance to play with my supplies yet, but here is a picture of what the AC adapter looks like ... think it will work?

Front

Back

hope that helps!!


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## majstor76 (Jun 11, 2010)

gregjonesonline said:


> I also picked up a slim push pump soap, and probably the most exciting part of all, I found a Universal AC Adapter which has a voltage selector to emulate a wide range of batteries, from 3 - 12 volts DC / 600mA. I haven't had a chance to play with my supplies yet, but here is a picture of what the AC adapter looks like ... think it will work?
> 
> Front
> 
> ...


I was going to borrow similar adapter from frend to see if it works, do report your findings. I was trying before with cellular charger of 5-6V and about 400mA but motor wouldnt budge. 600mA seems still kinda low. I dont know whats the safe voltage which circuits can receive without damage but i think if on 6V it doesnt work that it needs more amps


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## gregjonesonline (Jan 22, 2011)

From what I have read and see, the AirWick Freshmatic takes 2 Alkaline AA batteries in Series. Here is a description of series vs parallel: http://www.zbattery.com/Connecting-Batteries-in-Series-or-Parallel

Each AA (Alkaline) is 1.5 volts, so 2 in parallel is 3.0 volts
Each AA (Alkaline) is 2700–2900 mAh or 2.7 - 2.9 Amps, and in parallel this remains the same.
At 2700 mAh the batteries can provide 2.7 Amps over 1 hour before they die, and we know that the motor lasts more than an hour because the packaging says "lasts up to 60 days"

The AC adapter i picked up is 3 - 12 volts, so i'll set it at 3 volts to emulate 2 AA batteries. It's also 600 mA, and i can't really change that, but lesser adapters are only 500 mA, so i think my current will be more than fine.


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## majstor76 (Jun 11, 2010)

gregjonesonline said:


> The AC adapter i picked up is 3 - 12 volts, so i'll set it at 3 volts to emulate 2 AA batteries. It's also 600 mA, and i can't really change that, but lesser adapters are only 500 mA, so i think my current will be more than fine.


Well , theres only one way to find out... In meantime, im testing how long rechargable batteries can hold. Iv set timer to 9 min and will see. If it holds long enough to not be a burden to change the too often then maybe adapters would not be needed at all.


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## marek (Jan 22, 2011)

Nice hack , but I have two questions:
1. AFAIK you used built-in airwick time-based (time selectable by a switch) mechanism. This devices have internal squirts counter for "detecting" empty spray, when counter reach programmed limit (is notified by fast led flashing) device stops "pushing" until you press manual release button (it just reset the counter). Did you had any problem with that?

2. Did you test it only when dispenser is at the same water level in the tank (or a bit above)? I wonder if that will work when device is located below the tank with long "out" hose (about 1.5 meters) to the tank. I guess when fluid will flow slowly backwards (becouse of pump's leak) to the pump between squirts it will be unable get strict doses...


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## majstor76 (Jun 11, 2010)

marek said:


> Nice hack , but I have two questions:
> 1. AFAIK you used built-in airwick time-based (time selectable by a switch) mechanism. This devices have internal squirts counter for "detecting" empty spray, when counter reach programmed limit (is notified by fast led flashing) device stops "pushing" until you press manual release button (it just reset the counter). Did you had any problem with that?


I have never encountered such behaviour and have emptied few cans of spray on it in the past. This device is old few years, maybe new versions of devices have such thing but not old ones? 



marek said:


> 2. Did you test it only when dispenser is at the same water level in the tank (or a bit above)? I wonder if that will work when device is located below the tank with long "out" hose (about 1.5 meters) to the tank. I guess when fluid will flow slowly backwards (becouse of pump's leak) to the pump between squirts it will be unable get strict doses...


I have tested only with a pump on same level as water, ill do the test with long hose tommorow


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## DarkCobra (Jun 22, 2004)

majstor76 said:


> I have never encountered such behaviour and have emptied few cans of spray on it in the past. This device is old few years, maybe new versions of devices have such thing but not old ones?


I did find what appeared to be two versions of this dispenser online, with different electronics.

If the counter is an issue, it may be just a matter of routing the output to the LED to the input for the reset button. Light goes on and it thinks the button's been pressed. Might need a simple transistor switch to reverse the polarity, I don't know.

I wish I had one to experiment on now. And I am kicking myself remembering all of these I've seen at garage sales for $1.00 or less. One had four for sale.


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## majstor76 (Jun 11, 2010)

And in the other news, it seems im just a copy cat 

http://www.wattreport.com/2008/12/diy-adapt-airwick-freshmatic-to-accept-cheap-aerosol-spraycans/

BTW, mine device looks just like that in the link (well , outer shell at least) so if anyone is buying maybe it should find device like that and maybe therse no advanced electronics in it.


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## majstor76 (Jun 11, 2010)

I have started a test with output container on 180cm up from pump. But i have put check valve maybe 20 cm downstream from pump


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## majstor76 (Jun 11, 2010)

One guy at croatian forum had also good idea to use IR battery soap dispenser










He cut wires for IR and instead of batteries he used 4.5 DC adapter connected to timer. Every powering on drops about 2.5 ml of liquid.
These dispensers can be found for 10$ on Bay


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## marek (Jan 22, 2011)

majstor76 said:


> I have started a test with output container on 180cm up from pump. But i have put check valve maybe 20 cm downstream from pump


So, what about the results?


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## majstor76 (Jun 11, 2010)

marek said:


> So, what about the results?


I had a leak between blue hose and pump noozle so i had to fix that. Ill start again with test soon


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## majstor76 (Jun 11, 2010)

Well, i tested capability of wickpump to pump water on higher level (1.5 meter) and its a no go. It cant pump so high , so pump must be about on level of end of hose. 
Currently im using wickpump for fertilizing hydroponics setup and its working nice. No AC/DC power, just batteries but dont feel i need power adapter


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## gregjonesonline (Jan 22, 2011)

http://youtu.be/o-LtG42MO1Y after having my airwick auto-doser kicking around for a while i decided to make an instructional video on how to create majstor76's creation, give it a watch! it should explain how to make them.


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