By Request Let's take a look at an astronaut nebula projector. It seems a very popular thing on eBay these days and well, lots of selling platforms and it's being advertised everywhere. So what do you get? You get the little astronaut. The head is falling off the astronaut.

That's because it's held on by a magnet. Let's slap that on there. You get a sticky pad for sticking onto things. Is that velcro? No, it's actually.

it looks like you just stick it straight onto something. That's not a good idea. Uh, and you get a remote control and a Usb2 standard Jack connector for power. Let's power up and see what this looks like.

Here is a USB power supply. We'll plug it in and there are three very Anonymous buttons in the back. They are covered in the manual though the head has fallen off. Again, this isn't a good start.

I chose the one with the Star. By the way, you get a star or a guitar. uh which is the power button. The middle button is power that immediately starts shooting beams out and also activates the laser.

I'm not really thrilled about the fact that putting lasers willy-nilly in produ these days. The point of the magnetic head is you can spivel it to to se your requirements. he said shooting himself in the eye with a for mentioned laser. So we have the Nebula switch which lets you choose between the colors that are being projected by this and we'll take a look inside at that.

And you've also got the laser switch. and the odd thing about the laser is it ramps up and down now. I'll tell you what, Let me show you this. Let me turn the lights off and I'll show you what it looks like one moment please.

So here we go. It uses a standard system that it looks like it's got a rippled glass disc in front of LEDs that is ferociously bright bright. Let's see if we can tame that down a bit and the remote control gives you control over the nebula. You can turn it off completely if you want.

I Think if you press and hold it, it shuts it off and that just gives you the star field which is a fairly consistent pattern of dots and it fades in out. I Don't get the fade in out thing. let me, um, press the laser options. Oh, that's the intensity option.

laser on laser mode and the mode just seems to be different speeds of ramping up and down. There is a static one. if I can find static one, it lets you control the intensity to a degree. it does go Fairly Bright.

Um, always cautious about the use of these. Uh, in a place that you know people could get it in the eye so to speak. H but that is the static effect. It's the classic defraction grating going.

I'll turn the laser off now and we'll go back to the nebula mode. and uh, it lets you change the speed of the nebula. Auto Static as well and it also lets you change the brightness and also the colors of the nebula. I should hold it further away just so you get the more nebula effect.

it does spread across to quite a wide part across the ceiling. Okay, you've seen it working. Let's open it up right now. So the first thing I'm noticing here is that the little backpack here has the jack in and the cable out.

I Think all the electronics are in here I Could be wrong, but we find out in due course I shall unscrew that using whatever screwdriver actually fits that doesn't fit. This kind of fits. So we'll take the backpack. Well, we'll open the backpack and then we'll open the head.

I Could just pause while I do this. CU It's just taking screws out. One moment the screws are out. Let's zoom in to show that the little backpack really is just the power.

and uh, the three buttons and the B B They got two wires going up and then the three wirs for the for the power and then the three wires for the Uh buttons. So all the circuitry is on the top here. Let's get this off. There's the laser module which is hot milk glued in.

There is the optical assembly that we're interested in. Strange how it's got that little cup there. Um, is that just. oh.

it's just sitting in a little sort of bearing and it's got the motor driving from the side. Okay, right. Uh, I'll take more screws out then one moment, please. So now the screws are out.

I Have to say this is quite a novel approach quite often with these Edge driven effect feels and they're doing that for the maximum H coverage. They if they'd put this in a motor, then it would have limited the area that you could put in front of the LEDs. So by actually Edge driving it, it means that they've got the whole internal area. so the whole image, so to speak is rotating.

It's quite a Noel approach. And what's even more Noel is the fact they've just got it in this little receptacle like this so it can spin instead of having the usual Arrangement where you've got the contact there and then you've got another uh, supporting contct sort of triangulation approach. with uh bearings. this is a very cheap and easy way of doing it I Wonder how reliable it would be? although it does have a good long, large contact here.

The main circuit board has the motor in the back. there's the steel plate curved steel plate for the magnet uh in the actual the body of the unit so they can swivel about. It's nice enough approach and we've got an aluminium core PCB which is good for heat dissipation. Can this thing come off? Is this staked on? Oh, it's glued on, but we can probably tell there's going to be three LEDs under this right? Tell you what? I shall reverse engine in the circuit board and we'll explore the the circuitry I Don't think it's going to be too complicated, but well worth looking at one moment.

Please, Reverse engineering is complete. Let's explore and it's a very logical design. It's not too bad. I'll Zoom down this so we can just see a little bit more detail.

Here's the LED minus its lens. the lens Just Clips on it's got a bit of glue in the back to hold it in place and the LED is the three chips positive and it's got a resistor per LED 5.6 ohm for the red because it's got a lower voltage and then 3.3 ohm for the green and blue. Each of them has its own mosfet transistor with a 1K resistor to the gate and going straight to the microcontroller. The motor has a 4.7 Ohm resistor and uh, then it's got its own transistor which is a standard Npn style transistor, just a y1.

The laser over here has a 10 ohm resistor and it's got another mosfet in line with it. Uh, other things worth mentioning: the infrared sensor has a little rudimentary isolation power supply 4.7 ohm and a capacitor. The microcontroller has a diode and a capacitor and is just powered directly from the 5vt line. and the switches are all offboard, but just going straight to the microcontroller and use its internal pullup.

That is it. Let's take a look at the schematic: I shall zoom up just a little tiny bit more. Very typical stereotypical circuit. Here's the incoming Supply We' got the 5vt rail.

This bit is the offboard connector with its where is that little offboard connector? It is somewhere. it's it's just decided to hide. So anyway, there is that little offboard circuit board with the Uh main input connector and this of like the the switch connectors. there are two de covering capacitors on the input just just for filtering the 4.7 Ohm resistor for the infrared sensor with its little decover capacitor and that just provides a bit of uh noise filtering.

Oh, I've missed one value here. 1K The infrared sensor has the output via that 1K resistor to the microcontroller so it can just monitor for the data that is being received by the infrared receiver. There is a short key Diode Uh providing a Deced supply to this capacitor for the power supply for the microcontroller and then the microcontroller just has three switch Uh inputs and then switching to the Z volt. Rail And then it's got the Y1 transistor for the motor which is a 4.7 Ohm resistor in it to limit the maximum speed it can go.

Then the laser is treated like an LED it's got a 10 Ohm resistor. It is a three pin laser but they have just literally stuff this two pin connector on the two main pins. Oh, it's wobbling there. Oh, let just come out completely lovely.

The hot Nelt glue very effective and they've just disregarded the third pin and put a weed dot of glue in the back. Just hold it in place. They've actually kind of glued it to the third pin. That's unusual, but it is Switched by the classic A2shb mosfet and Chan mosfet with a 1K gate resistor.

Then we've got I've just missed these links out just to make it easier to see. We've got the red, green and blue, LEDs I shall draw little beams of light coming out of them and they have their own resistors. 5.6 ohm for the red, 3.3 ohm for the green and blue and just going to the mosfet. It is a very straightforward, minimalist design, but it's a fairly robust design.

Things it wins points for are that aluminium core circuit board which is going to provide good heat sinking for the LED array and uh, that is it. Again, the no. Most notable things here are this really nice sort of tray for the Distortion disc. this is what they used to call it in the old optokinetics days.

I Think optokinetics are still about but their uh effects Wheels They used to call this a distortion disc because it's got that of patterned glass. In this case, it's patterned plastic. the Ripple plastic and then that is focused through this. oh, I'm actually seeing the defraction grate in there for the Um Al so you can see the color reflecting off it for the laser.

H It's very straightforward. It's a very basic circuit. so there we have it. That is the nebula projecting Spaceman thing.

It's quite a nice package. still not comfortable. The laser here. There is something here I Don't know if this was designed to have a little speaker in it, maybe for Ambient sound or maybe it was going to be a microphone for sensing audio for just maybe pulsing to the beat of Music That's horrible when they do stuff like that.

But there we have it. A nice, simple, straightforward and functional design with a bit of hackability. The motor screws directly onto the back of this circuit board with two self tappers. It's got that longer shaft with the the small Drive Cog wheel in the end of it and that uh means that this whole module if you wanted.

If you were just looking for the ripple effect, you could just rip this out and just use that in its own. But there we have it. the Aurora nebula projecting Spaceman Not bad. Not bad at all.