Pages: [1]   Go Down
Author Topic: Powering an Arduino from 110 AC and Relays Project  (Read 437 times)
0 Members and 1 Guest are viewing this topic.
Offline Offline
Newbie
*
Karma: 0
Posts: 7
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Hi folks,

I'm planning to control wirelessly the lights of my house using attiny85 and relays. Since I'm already connecting some part of the circuit (i.e., the relay) to the main power line, i'd like to know if is there any way to power the mc without using an external wall wart adapter. The key point in this project is that I need things to be small, so I can fit them inside the wall switch.
Logged

United Kingdom
Offline Offline
Tesla Member
***
Karma: 224
Posts: 6616
Hofstadter's Law: It always takes longer than you expect, even when you take into account Hofstadter's Law.
View Profile
WWW
 Bigger Bigger  Smaller Smaller  Reset Reset

If the power requirement is just a few mA and you are able to insulate the electronics from the user, then it's possible to use a capacitor-rectifier-zener diode arrangement. But as you will be powering relays, you probably need more current than that, unless you can replace the relays by opto triacs. The smallest 5V power supply I found (without trying very hard) was http://uk.farnell.com/myrra/47122/power-supply-2-75w-5vdc-reg/dp/1825773.
Logged

Formal verification of safety-critical software, software development, and electronic design and prototyping. See http://www.eschertech.com. Please do not ask for unpaid help via PM, use the forum.

Left Coast, CA (USA)
Offline Offline
Brattain Member
*****
Karma: 361
Posts: 17294
Measurement changes behavior
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Hi folks,

I'm planning to control wirelessly the lights of my house using attiny85 and relays. Since I'm already connecting some part of the circuit (i.e., the relay) to the main power line, i'd like to know if is there any way to power the mc without using an external wall wart adapter. The key point in this project is that I need things to be small, so I can fit them inside the wall switch.

In theory, yes there are and there is such circuitry methods published on the web. But I would fall back on the 'if you have to ask you probably shouldn't be messing with it' line. There is always risks of fire and human safety when DIY methods are applied to household power circuits and I try not to encourage such projects but rather suggest you always use fully UL approved components and assemblies for such applications.

Lefty
Logged

Offline Offline
Newbie
*
Karma: 0
Posts: 7
View Profile
 Bigger Bigger  Smaller Smaller  Reset Reset

Thanks for the replies. Probably I will go for the solution posted by dc42.
Logged

Pages: [1]   Go Up
Jump to: