• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Designing a POV Clock

Status
Not open for further replies.

ThreadAbort

New Member
Hello,

I am very strong in digital electronics, but have a few weaknesses in analog. So, my question could be simple for some of you.

I am designing a Persistance of Vision clock that spins on a motor. This clock needs to have power on the spinning circuit board. I see 3 options on doing this.

1. Battery (won't last long)
2. Brushes (I don't know how reliable and long that would last)
3. Magnets on the main board with a circular pcb board that has small inductors on the bottom of it. A generator of sorts.

I am really interested in trying option 3. But, I don't know if it even worth trying. The pcb requires about 500 ma at 3.3 volts. So, I am beginning to think the best option might be 2.

Any other ideas would be much appreciated.

Thanks for your time,
Chris
 

dougy83

Well-Known Member
I've seen option 2 used for this application before. You'll want a moderate-sized supply-bypassing cap on the spinning board as the brushes may not be in constant contact. The use of multiple brush fingers will also improve reliability.

Another option is using a transformer-coupled supply. e.g. 2 halves of a pot core with the rotation axle through the centre. 1 half on the rotor pcb, 1 on the stator. Switch the stationary coil at a high frequency.
 

marcbarker

New Member
spring-loaded pencil lead makes good brushes on a circular PCB.
hall sensors are handy too
 
Last edited:

dougy83

Well-Known Member
hall sensors are handy too
Ah, yes, to detect the position of the spinning pcb. Another solution for this (if you're using brushes), is to put an intentional break the pcb brush ring which can be detected (from the supply line) by the micro.
 

Mr RB

Well-Known Member
Get a head assembly from any junked video recorder. It contains a highly efficient rotary transformer which if i remember correctly was good for transfer of about about 100mA (wasn't me that tested it). And it's got a low power brushless motor on the bottom to spin it.
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top