Cheap Power

I am working on a temp controller for a kegerator (Temp Controller Thread) and I would like to loose the wall wort for something that could be mounted internally to power the arduino off the 120v power to the fridge. I am thinking of using this Cheap AC DC Converter but before I go down this road I wanted to ask if anyone has a suggestion on a better power supply that won’t cost too much.

Well, it's probably fairly safe but without a "UL" listing or similar I would

  • mount it in a relatively fireproof grounded metal case and
  • use a grounded power lead to ground the low voltage negative.

Thanks for the advice. What about this not quite as cheap AC DC converter? It looks a lot safer but is 6V enough? what is the voltage drop on the arduino power regulator?

Anyone used anything better or cheaper?

I would like to loose the wall wort for something that could be mounted internally to power the arduino off the 120v power to the fridge

Does mounted internally mean in the cooling chamber? You want to power the arduino from 120V, so why give up the wall wort? Cheap. You may just need to wire a plug for it inside the fridge.

Working with 120v can be dangerous, so if you may want to have an electrician do the wiring for you.

[quote author=jack wp date=1437491529 link=msg=2324376] I would like to loose the wall wort for something that could be mounted internally to power the arduino off the 120v power to the fridge

Does mounted internally mean in the cooling chamber? You want to power the arduino from 120V, so why give up the wall wort? Cheap. You may just need to wire a plug for it inside the fridge.

Working with 120v can be dangerous, so if you may want to have an electrician do the wiring for you.

[/quote]

Very good point and in no way will I consider high voltage in the cooling chamber with risk of condensation. The only reason I don't want to use a wall plug is that there is very limited space in the area where power comes into the compressor. I could probably make it fit but it wouldn't be fun.

Another Option I'm looking at

Also looks like 6v will not work based on what I have found Here

Paul__B: Well, it's probably fairly safe but without a "UL" listing or similar I would

  • mount it in a relatively fireproof grounded metal case and
  • use a grounded power lead to ground the low voltage negative.

Good advice Paul. The lack of safety approval is because it wouldn't comply with the standards as it has exposed live parts. It is considered a component, not a finished product.

Russell.

Which arduino are you using?

You want to provide 7v to 12V looks like.

Just curious, what is the application for. I could only guess 3. 1. the thermostat that was there went bad. 2. wine cooler. 3. store eggs before putting them in the incubator.

[quote author=jack wp link=msg=2324492 date=1437496989] Which arduino are you using?

You want to provide 7v to 12V looks like.

Just curious, what is the application for. I could only guess 3. 1. the thermostat that was there went bad. 2. wine cooler. 3. store eggs before putting them in the incubator.

[/quote]

I built a kegerator out of an old chest freezer and the existing thermostat could not operate in the range I needed for beer. I used an old johnson controls mercury bulb thermostat and it worked ok... kinda. I recorded the temp for a while and it was swinging between 15 degrees and about 48 degrees which doesn't mean the beer swings that much but I just wanted to do this for the heck of it. Next I will be adding load cells to measure how much beer is left when it starts pouring.

Project thread is here.

Oh and I'm using the Micro

[quote author=jack wp date=1437496989 link=msg=2324492] You want to provide 7v to 12V looks like. [/quote] Depends.

If you primarily want to power the Arduino at 5V and all associated components operate at 5V (or less), that you actually want a 5V regulated supply.

The regulator on the Arduino is only provided in case you do not have a 5V regulated supply. If you can choose a power supply to suit, then it would be 5V regulated.

Paul__B: Depends.

If you primarily want to power the Arduino at 5V and all associated components operate at 5V (or less), that you actually want a 5V regulated supply.

The regulator on the Arduino is only provided in case you do not have a 5V regulated supply. If you can choose a power supply to suit, then it would be 5V regulated.

How would you do that see the specs here for the uno. It states you need 7-12v input. If I need more 5v power than the board can supply then I would add a 5v supply but everything I have is fed of the Arduino.

Input Voltage (recommended) 7-12V Input Voltage (limits) 6-20V

I have provided 5v to the 5v pin without problems, but the documentation says it is not advisable

5V.This pin outputs a regulated 5V from the regulator on the board. The board can be supplied with power either from the DC power jack (7 - 12V), the USB connector (5V), or the VIN pin of the board (7-12V). Supplying voltage via the 5V or 3.3V pins bypasses the regulator, and can damage your board. We don't advise it.

if the ‘5v supply’ is not 5v you can/will destroy the Arduino.

You cannot feed the 3.3v input(with 3.3V) and expect 5v output. but feeding 5v into the 5V pin will produce 3.3v out the 3.3V pin.

They are just recommending you use the internal regulator to supply current for the Arduino. The Vin circuit has overcurrent, protection.

Chuck.

It is indeed, not advisable, if you do not understand what you are doing. :grinning:

It’s called the “standard disclaimer”. No user-serviceable parts inside.

(Like the human body?)

The first link brings to an Ac-Dc with a Voltage input of 240 V, pay attention!

@paofanello, I am not sure which link you are talking about. I noticed the second link spoke of input of 90-240v. Is that the one?

The OP first post said he wants to use 120 volts.

Maybe if you post the link? I am really trying to pay attention!

And what is the point of the link?

paofanello:
The first link brings to an Ac-Dc with a Voltage input of 240 V, pay attention!

The first link here is for a $1.99 AC-DC converter that is not UL listed.

The specs are as follows so it would work and is not 240V! However it not being UL listed means I might catch my house on fire if I don’t install it correctly and I am not an electrician. Luckily my friend is so I might give it a try and I can waste the $1.99. Really if anyone has done this before let me know if you have a better suggestion. The goal is to completely replace the existing freezer controls so that it is a kegerator (that also tells me how much beer is left by weighing the kegs) and still only have one plug not a plug for the kegerator plus a wall wort!

  • Input voltage : AC90~240V 50/60 HZ
  • Output voltage: DC9V (±0.1V)
  • Output current: 500MA
  • Power: 4.5 W
  • Size:302018(mm)