Continue to Site

Welcome to

Welcome to our site! is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

"Propeller Clock" Mechanically Scanned LED Clock

Not open for further replies.


Full Member level 5
Sep 23, 2002
Reaction score
Trophy points
Activity points
propeller clock avr

hi all

this is nice clock


s 8O krat

propeller clock

ummm, *what* is a nice clock ? There's no link or anything in your post ...

avr propeller clock

i 'm so sorry :oops: :oops: :oops:

this is link

**broken link removed**

have fun




propeller clock circuit

Elektuur (elektor)
Mentioned it last month or so.. looks intresting.
Just wondering Will it make lot's of noice?
I mean, what if I'm watching TV or reading the forrum. not to be disturbed... :lol:
Anyone build it?

mechanically scanned led clock

Hello All ,

I´m new on this forum so this reply is a little bit late but anyway.

I just finished with building such a clock based on 80c51 microcontroller instead of a pic microcontroller . The biggest problem is to provide power on the electronic part that is spinning around .
i used a dc ventilator like it was described on the website of henk soubry
(see link in elektor) but a 24V one instead of a 12V ventilator .

The noise production depends on the size of the propellor PCB and the balance of the PCB.

At the moment i´m looking for a cover for safety reasons and believe that it will also reduce the noise .


led propeller clock

DC ventilator ? You mean transformer ? Can you show your circuit and maybe pics of your setup ? I have played a bit with the transformer idea without much luck, and it appears others have had trouble as well.

This is Henk's site. Very nice looking clock, and doesn't seem too loud in the video.

**broken link removed**

henk soubry clock

Hello Panalog,

Actually i did use a DC ventilator (brushless) to build the transformer .
The secundairy winding is wraped around the permanent magnet of the dc ventilator . The primairy lays on a cardboard cylinder or anything else that fits over the turning part of dc ventilator .Please nottice that the secondary may not lay over a metalic part(See explanation further) . Instead of cardboard i made a plastic kind of mall where the dc ventilator fits into it . Please find in the attachment some pictures of my setup and my clock .I have a schematic but it is made in protel. at the moment i can not print it out in pdf but if you want to i can do this later on this week .

I tried to use a VCR drum instead of the ventilator but with no results .

Some words about the transformer.

The principal of this transformer is based on the flyback topology.
In a normal transformer current is flowing into the prim. and sec. at the same time . The core material of the transformer is iron like material.There is no possibility to store energy in the coils due to the magnetic core.

A flyback transformer is in fact a boost converter . the primairy winding is connected to a switch (N-MOSFET). Current is flowing in one winding at the same time. When the switch is closed , current flows through the primairy winding and energy is stored in the coil .This is the reason why the primairy winding may not lay around something metalic. The energy will be dispated as heat in the metalic core .When the switch opens the energy from the primairy winding is transfered to the seconduary winding through an air gap . The air gap is coupled with a permanent magnet where the secundairy lays on .On this way you get energy in the secundairy .Below are some usefull links where i find the discribed information


I hope this will help you a little bit forward

Kind Regards,

propeller clock mechanically scanned led clock

Here is an AVR based propeller clock:
**broken link removed**

pic propeller clock

gandalf -

Thank you very much for the description. That is pretty much how I was testing it. I use Pr0tel 99SE, so should be able to open your sch.

The cup that holds the magnet for the fan (ventilator ! aha !) has the secondary winding around it. If it is metal, the metal will short-circuit the field from the primary, and no power will go across.

This is what I've seen myself. Secondary around a metal cup - I see good voltage at the secondary, but not enough current to light LEDs.

Yet Henk does exactly that - secondary around a metal cup. His forum describes this, and he doesn't know why it *does* work for him. Strange.

What frequency did you find to work best ?

Cheers -

henk soubry

Why don't you just use the solution posted in my earlier post for transferring power to the circuit. This solution is much easier I think.

Look at these two pictures:

**broken link removed****broken link removed**

avr clock propeller

Hello ,

Sorry but i missed your links . Probabbly the replys where crossing each other i suppose .
I was wondering what the noise is that the brushes generated .
This was the reason why i looked for an alternative.

In my case 9 Khz with a duty cycle of 50 % was ok . I tested it with a function generator with variabel duty cycle . Just one detail the phase of the coils must be in oposit direction .

To panalog i can only say this .

If you look at one of the links in my previous post you can find that the secundary must be coupled through a magnet in order to have a flyback

In the attachment you can find the schematic

Regards and good luck ,


propeller clock pcb

I don't think ther will be any noise problem from the brushes, if you use a charge capacitor and decoupling caps.

propeller clock using 8051 microcontroller

Hello again ,

I forgot something in my previous posting.

My clock is working with power supply of 12 V .
and the frequency depends on the amount of windings.

In general how lower the windings how lower the frequency that you can use .
This is something that you have to find out by yourself through trial and error . In my case i used 100/170


propellor clock

Hello ,

I think there is a misunderstanding concerning the noise item
i mean the hearable noise that it will produce .

Sorry for this


brushless propeller clock

Sorry for the misunderstanding.
I don't think you will be able to hear it at all.
Remeber that the motor itself contains brushes inside anyway, and you can't hear them. You just add another set of brushes. I think the motor will make more noise than the brushes.

I think you should just send an email to the maker of this AVR clock, to ask about the brushes and other questions regarding the design.
I'm sure he is willing to answer your questions.
His email address can be found here: **broken link removed**

propeller clock with avr

I built Henk Soubry clock and the transformer works great. Some say the transformer gets hot but mine runs fine and does not get too hot. This tranformer is the way to go...

Re: "Propeller Clock" Use AT89S52

Hello all,
I used 89s52, too
Please help me about program for my propeller. If you can, you're write Asembly because i just learn it.
I very enjoy if my text have many effect exam: up, down, run to left, run to right.
my mail:

Re: "Propeller Clock" Mechanically Scanned LED Clo

I'm trying to make a propeller clock with 22 LEDs and was wondering if I can help with handcuffs programming ...:confused:... in part to pass the information that the PCF8583 fornesi my PIC (16F877) and passes it to the LEDs ... was shackled to help me say something ... thanks;)

ps.: I'm working with miKroC

Not open for further replies.

Part and Inventory Search

Welcome to