Power Supply Designing for Arduino Project

[andrea05256]

Hi,

We have designed an Arduino Project which we have completed perfectly, its a biomedical device. Now, we want to design its power supply, as we can't keep the battery in it, want to keep it light-weight.

So, we need to design a 240VAC to 5VDC and it shouldn't be based on transformer, as its quite heavy.

We have searched onlien and found this: https://www.pcbway.com/blog/technol...rless_Power_Supply_Using_LNK304_5b2e2d7d.html we are looking for similar design as its small in size and quite light weight.

Can someone please confirm that this circuit is good to start working on.

If someone could provide us the pcb design, it would be really helpful.

Thanks.

 

[For The Popcorn]

A medical device connected to the body has strigent power supply requirements to prevent any possibility of shock. A transformerless supply is never safe where a person can come into contact with any part of it – this type of supply clearly does not meet medical device requirements.

 

[andrea05256]

it will be like a laptop's power supply, long wire and we will make sure to keep it safe from any electrical hazard. It's a college project so they give such requirements.

 

[For The Popcorn]

Same comment. A transformerless power supply is not safe for human contact with any part of the circuit.

Even a standard 5 volt USB power supply will have about half-supply voltage on the output.

 

[Pommie]

In the 80s a friend of mine designed a portable, battery powered ECG. Due to regulations, it had to be impossible to use it whilst it was charging. Medically approved power supplies are extremely expensive.

Mike.

 

[Nigel Goodwin]

I agree with everyone else - battery only - and if it's rechargeable, it MUST be disabled during charging.

 

[danadak]

Medical standard -

IEC 60601 :​

IEC 60601 - Wikipedia

en.wikipedia.org

Regards, Dana.

 

[rjenkinsgb]

it will be like a laptop's power supply, long wire and we will make sure to keep it safe from any electrical hazard. It's a college project so they give such requirements.

Just to bluntly make clear what others are saying:

A transformerless supply leaves the device it is connected to "Live" to the AC power.
Long wires do not change that!

Touching anything connected to it is likely to cause a serious electric shock, or death.

 

[For The Popcorn]

The original poster has been here since all of these warnings have been posted. And not made any reply. Let's hope that he's taken them to heart and not continued with "it's only a college project, so it doesn't matter." Or that his professor sees the problem before anyone is hurt.

 

[Nigel Goodwin]

The original poster has been here since all of these warnings have been posted. And not made any reply. Let's hope that he's taken them to heart and not continued with "it's only a college project, so it doesn't matter." Or that his professor sees the problem before anyone is hurt.

Needless to say, it's from the usual part of the world where there seems a complete lack of safety among college instructors - even as a purely theoretical exercise, it should never be assigned.

 

[tepalia02]

Shouldn't there be a regulator IC too? What do you say, friends?

 

[atferrari]

Shouldn't there be a regulator IC too? What do you say, friends?

That you did not understand all replies provided.
Are you a troll?

 

[tepalia02]

That you did not understand all replies provided.
Are you a troll?

No. I am just new here and I admit that I know less than almost everyone here. I saw the posted design. I was expecting to see an LM7805 at the output part. Yes, I saw the replies too. To the best of my knowledge, I didn't see any discussion here regarding a regulator. This is why I asked. Thank you.

 

[Pommie]

Posters were worried that medical procedures were not being followed and therefore gave advice rather than a schematic.

Powering any device that attaches to a human (or, presumably, animal) should never be connected to mains power - or anything that could prove lethal.

Mike.

 

[rjenkinsgb]

I saw the posted design.

What, where??

The only schematic in the thread, unless I'm cracking up, was the original posters dangerous live-to mains PSU.
And that did have a 7805 (well, 78M05) for output regulation.

 

[Nigel Goodwin]

What, where??

The only schematic in the thread, unless I'm cracking up, was the original posters dangerous live-to mains PSU.
And that did have a 7805 (well, 78M05) for output regulation.

He seems to be posting random rubbish to old threads?. rather bizarre

I suspect all the mods are keeping an eye on him.