Mamod Disco!

mc_mc · Mamod Disco!

Inspired by IndianaRog's fantastic dynamo project built from a stepper motor with a rectification circuit I thought I would have a go myself.

I thought I would try something a bit simpler to start with, just a bog standard DC motor powering a few LEDs. The motor came from a old CDROM drive and was the CD tray eject motor which used a simple belt drive so the motor was already fitted with a plastic pully to make life eaiser.

I ordered some LEDs online and got these: http://www.ledshoppe.com/Product/led/LE4005.htm 20 multi colour flashing LEDs for $7 (£3.50) including free shipping. They take approx 3v to light up and I just guessed that would be about right.

When the LEDs arrived I attached one to the motor leads and span the pully with my fingers and was pleased to see a flash from the LED so I was lucky with my volatage selection.

The next test was to fire up an engine and attach an elastic band between the engine pully and motor pully and see what happened at this point I was just holding the motor in my hand to maintain tension on the band. This all worked fine too but it was a bit awkward to hold the motor and do things like oiling the engine so the next step was to mount it on a proper base.

I stole a bit of chip board from a skip at work to use as my base, not pretty but should do the job well enough I thought. Since the motor is round it's slightly more tricky to mount than Rog's square stepper motor. In the end I cut a strip from a 7-Up soft drinks can (but any brand should do!), drilled two holes in the end and screwed it to my base wrapped round the motor, I refined the design by cutting a bit of leather to go between the motor and the metal strip to hold things nice and firm.

Next step was to attach more LEDs to the motor leads making sure they all have the same polarity (one of the leads is longer to indicate the positive side of the LED, if you connect them up the wrong way they don't light to you just swap them round or just spin the motor in the oposite direction). For the test you see on the Video I attached 6 of the LEDs but I've now tried it with 9 was good results.

I also decided to use a proper mamod metal band as the elasic band was a bit too springy.

Here are a couple of videos of my efforts:

Next job is to run it in the dark and see what it looks like and see how many LEDS I can get it to light. I think this setup would work well for converting a traction engine into a showman's engine, the multicolour flashing LEDs would look very pretty!

It is quite amusing to think what's happening: Chemical energy is realsed from the meths by the burner converting it into heat energy. The heat energy is converted by the boiler into mechanical steam pressure. The steam pressure energy is converted by the cylinder into mechanical energy which is then transmitted along the drive band to the dynamo which converts it into electrical energy. The electrical energy is then finally converted into light energy by the LEDs. It's amazing it works at all really and is probably a good scientific instructional tool for a child.

tmuir

Nice one, you could probably get quiet a lot of LEDs connected to that as they draw next to no current.

So when is the Showman's conversion going to take place?

Sandman

Magic mate.

I've got a few old cd roms lying about that will suffice nicely.

Great idea.

Mister Occlusion

Spiffy!

I'm playing with LEDs myself, because one thing I notice (other than getting more lamps lit per generator), is that they don't slow down the engine like an incandescent bulb will.

One thing: for some reason you're supposed to have a current-limiting resistor in the circuit to provide a load. Something around 330ohm for low voltage. Reason being that otherwise it is essentially a short circuit that you have there, since LEDs themselves do not count as a load since they are fully conductive in the direction of current flow. The ultrabright LEDs I just bought even specify this on the package (though I had to get the resistance values elsewhere).

I have no idea if this applies for generators. I've only seen it referenced for building "LED Light Bulbs" to put into flash lights, etc (running from batteries). I can see why you don't want to short circuit a battery.

...I hadn't thought about using a CD-ROM motor. Here I am, trying to find a busted old printer to pull a stepper from when I've got piles of CD-ROMs and floppy drives laying about!
CD-ROM should have a stepper motor in it as well, attached to a worm gear that drives the lens assembly. Same for the head positioning motor in a floppy drive.

Thanks for getting my brain going

seven.mpd

Most illuminating post !

IndianaRog

MC....great to see what you have coming together there...quite sparkly as well. Glad to see you and others experimenting with this stuff...it is quite enjoyable to makes something out of discards etc.

cheers,
Rog

oldstuff

Great to see it all come about like that, Mike. Funny how things sometimes go in
cycles, as I just pulled a little motor from a VCR a few days ago to experiment with!

Good to know you can get several leds going from one motor!

mc_mc

Get down with it man...

James

LMFAO!!

Great video!

My MM1 definately went to a good home

Badger

That is so funny!! Made my day that has

Get down you funky steamer

IndianaRog

Mike, I could swear those LED's were blinking to the tune...very neat effect...the Bee Gees could have used you and your MM1 !!!

Wallace

Great stuff mc

Nice videos

Sandman

Brilliant Vid.

Mamodman123

Brilliant!

Badger

On second thoughts....I've had the bloody Bee Gees stuck in my head all day!!

tmuir

LMAO!

That was brill!

May I suggest for MkII you go to your local discount shop and buy one of the 1 or 2 inch mirror balls and have that driven off a line shaft and get that disco vibe really happening.

Graham-Jilly

great vid well done

flywheel61

Lots of fun with a bit of lateral thinking thrown in, good one.

Cheers

Chris

mc_mc

Thanks for all the kind comments, glad you enjoyed it. The BeeGees were dubbed on afterwards so the lights weren't flashing in time to the music just randomly.

But adding some glitter balls is a good idea.

I've now managed to light up 12 LEDs using my SE1a. If I add any more the back EMF causes the dynamo to stall as it's too difficult for the driveband overcome the rotor's torque.

Measuring with a volt meter it seems the the voltage produced by the dynamo is about 2.5v but constantly fluctuates between about 2.3v and 2.7v. I hope to see if I can use this to power a small radio and so maybe get the engine to produce music!

I need to measure the resistance of my LEDs then I can work out what current is being delivered. V=IR

Mamodman123

rangerssteamtoys

Now mount the lights overtop the steam engine thats powering them and make it look cool, like a steam disco.

Titan

That is absolutely fantastic!! Sometime in the I want to build LED lamps for the station on the portable layout and have them powered by steam. Might give the flashing LEDs a miss mind !!

rangerssteamtoys

I decided to try your idea and it worked. I got out my old computer and hacked it to bits to get the motor from the CD eject system. I hooked it up to one of my engines and got instantly 2.5 volts. I amy going to keep working with this system and see what I get.

Titan

I really must get Titans dynamo sorted, trouble is finding a decent motor that is small enough. I have a micro-scalextric motor which is about the right size, but it is open frame and square and a bit long so somewhat less dynamo looking. I do have one or two old disk drives that might yield something - will have to get digging!!

Cranko

Hi, Brilliant idea, Will any small motor work as a generator or do they they have to meet a criteria? Hope someone can help a not very electrical person here

Mister Occlusion

IndianaRog

Any small motor such as a 2 wire Meccano DC motor will become a generator when spun at sufficient speed.

With the stepper motors taken from computers, printers and similar...there are often more wires to deal with. Mine had 6 total, two of which were joined to become one lead and the other 4 had to be wired thru 4 diodes and then combined together into the other lead.

I do NOT understand WHAT I did, but I was good at following directions and documented it on my website. Such motors work very, very well as DC generators!!

Dauntless

top job mate! that song goes great with the flashing lights too

mc_mc

rangerssteamtoys

I hooked my generator to my midwest and ran it on a little air and got a high of 6.2 volts. I was realy amazed and thought I could run a small light on it. BUT it doesnt have near the amps to light a small 1.5 volt light taken from a flashlight. I did however get a small motor from the computer to run and put a prop on it and it ran fine. And I did get a small led to light up.