gyro_gearloose

Hi I've had a look at the photos and its completely clear where the original lamp fits. It looks like the two motors under the red connector might get in the way of an LED and its heatsink. Where is the lamps reflector? Also, I can see what looks like the ballast and ignitor for the lamp, but where is the power supply for the electronics? Could you take some more more photos of the lights, especially where the original lamp sits? Thanks

Hmmm.... I haven't seen a 1016 before. Any chance you could pop the covers off and take a few photos? It'll help me determine how much space there will be for the LED and it power supply.

Which Roboscans have you got? I thought they only used 250 and 575 Watt lamps? Whichever they are it shouldn't be too hard to convert them to LED, there's just more space in the bigger 918. The only tricky bit will be the lack of condensing optics in the Roboscans. My Miniscans had an aspheric and a convex lens next to the lamp, which I kept when I converted to LED. These lenses collect more of the light than a simple reflector will, especially from an LED as all of the light gets projected forwards. I can certainly have a look at converting your Roboscans to LED. Let me know which model you have (812, 518, or 918) and how bright you'd like to go and we can go from there.

.....or the OP could just buy or hire a few Selecon Pacifics and print their own multicolour gobos on a desktop printer. Much cheaper and nowhere near as messy as etching your own gobos.

Actually its a little more complicated than that. Have a look here

Not yet, but I'll be converting another of my Miniscans soon and running that at 1000mA, so I'll be able to compare it to the first Miniscan that I converted. If its significantly brighter and doesn't get noticeably warmer then I'll change the first one I built to 1000mA instead of 800mA.

The 90W LED is just a scaled up version of the 40W LED that I'm using. The 90W version uses four strings of LEDs at around 20-ish volts per string. You'd need four separate LED drivers, and a 24V 100W power supply. I use these LED dynamics drivers as they are fairly cheap and do what I need them to do. I wouldn't use the cool white LED though as its a bit too blue. The neutral or warm white LEDs might be a bit better. Edit: Even though I'm using two 1A drivers, I have used their control pins to throttle the LED current back to just under 800mA. Its not really recommended to run the LEDEngin LEDs at 1000mA unless you can keep their junction temperatures down. Since my LED doesn't even get warm, I may try running it at 1000mA to see what happens.

Fitting the 90W LED would be straight forward enough, but what would really get heads turning would be the 90W LED in something like a Coemar Prospot 250 or Robe 250 (which use condenser optics so would be easy to convert) or a Mac 250 (which doesn't use condenser optics so I would have to make my own). Watch this space.......( but also don't hold your breath :) )

I ended up using conductive epoxy as I was wary of cooking the LED if I tried to solder it by hand. I only have a 25W iron and it couldn't heat the LED fast enough for the solder to melt! To be honest the epoxy wasn't particularly easy to use either. It takes 24 hours to set, and even then I had to keep it above 25 degrees or it wouldn't have set at all. Not an easy task in the middle of winter. In the end I pointed a pair of birdies at the LED to keep it warm. Once it had set I then encapsulated the conductive epoxy in regular epoxy to give it some strength as it would have been too brittle without it. As for how the LED is powered, I simply wired the LEDs power supply so that it comes on as soon as the unit is switched on. The dimming is mechanical using the original shutters, and the lamp stays constantly at full. However the drivers I am using have the option to attach a switch so I could fit some microswitches that are activated when the shutters are closed. This would turn the LED off when the shutters are closed and help reduce power consumption still further. There wouldn't be any problem with doing this as LEDs turn on and off instantly without the 5-10 minutes warm-up time that discharge lamps need. I removed the interlock as the plate it is attached to gets in the way of the heatsink. I don't need it anyway as there is now no need to open the hatch. The thumb bolt can be replaced with a regular bolt to prevent people from gaining access to any live parts.

I've turned the fan around so that it is pushing air directly over the heatsink rather than relying on the airflow through the unit to cool the LED. I'm not worried at all about the motors heating themselves up as the greatest source of heat in the original Miniscan was the HMI lamp. The lamp alone puts out so much heat that it gets the entire metal body of the unit quite warm, and this in turn gently cooks the stepper motors. Heres a pic showing the LED and heatsink mounted in the Miniscan. The big silver box next to the LED is the power supply. http://i157.photobucket.com/albums/t41/gyro_gearloose/ledcloseup.jpg If anyone is interested in converting their Miniscans let me know. I can supply the plastic and metal parts, and put together a guide on how to do it yourself. You would then need to supply the LED, LED drivers, heatsink, and power supply. You would also need to wire up the LED. This might be a bit tricky as it is impossible to solder anything to the LEDs metal clad PCB with a soldering iron. I ended up using conductive epoxy, which is quite expensive and time consuming to use. Because of this I could wire up the LED for you if you wanted. Anyway, let me know if any of you are interested.

The LED heatsink still needs a fan as without one it does get warm. Since I don't know that much about design cooling systems I have erred on the side of caution by using such a large heatsink, though I could probably slow the fan down quite a bit. According to the datasheet for the LED, the total thermal resistance for the LED and its metal clad PCB is 1.3 degrees per Watt. So, as I understand it, since the LED is 40 Watts the LED will reach 40*1.3=52 degrees above ambient temperature. The LED is actually made up from two strings of six LEDs, so while the LED as a whole needs around 42V I only need to supply two 20-ish volt supplies. I've done it this way because LED drivers are more readily available for 24V supplies than 42V supplies.

I've taken the larger of the two fans out (the one that sits under the lamp/lens holder) as it isn't really needed. I've kept the smaller fan, but had to turn it round so that it sucks air into the fixture rather than pulls it out. Its still a little noisy, though that could be solved by cutting out the grill which is cast into the body of the unit and replacing it with a wire fan grill. I'm not sure why Clay Paky didn't do this themselves as the holes they've left strangle the fans performance and create a lot of the noise by causing turbulence.

Well the LED should last for 100,000 hours until the light output has dropped to 70% of its initial brightness. If we set a realistic life of around 50,000 hours to maintain brightness levels, then I would need 50 HMI 300 lamps. Assuming they are £75 pounds each, 50 lamps would cost around £3750. Now I know what I'm doing it would cost me around £120 in parts to make myself another complete LED unit consisting of the LED, the plastic body, power supply, LED drivers, heatsink, and nuts, bolts, and wiring. And power requirements are reduced to around 90W instead of 900W per unit.

Having braved the cold out in my garage, I've finally managed to finish my Miniscan LED conversion and I must say I am very pleased with the results. Here's a few photos showing the output of my LED miniscan alongside an HMI300 Miniscan. Can you guess which ones which? White: http://i157.photobucket.com/albums/t41/gyro_gearloose/miniscanswhite.jpg Red: http://i157.photobucket.com/albums/t41/gyro_gearloose/miniscansred.jpg Green (apparently): http://i157.photobucket.com/albums/t41/gyro_gearloose/miniscansgreen.jpg Blue: http://i157.photobucket.com/albums/t41/gyro_gearloose/miniscansblue.jpg http://i157.photobucket.com/albums/t41/gyro_gearloose/miniscansgobos.jpg The LED Miniscan is on the right in each of the photos. Sorry for the poor quality. I'm not sure why the colours didn't quite come out as well as they should have. They are much more saturated in real life than in the photos. It might be my cameras white balance. The gobos were both focussed as sharply as I could get them, and most of the bluriness is down to the simplicity of the Miniscans single lens projection system. I think that tweaking the position of the LED in relation to the condensor lenses may help though. The LED is noticeably bluer than the HMI lamp, which surprised me. I chose a cool white LED so I expected a certain amount of blue-ness to the beam, but not as much as I appear to be getting. Playing with the Miniscans in-built warm filter brought the LEDs apparent colour temperature down closer to that of the uncorrected HMI. I'm not using the warm filter in the photos. Without the aid of light meter (which I understand can be quite innacurate when measuring LEDs anyway) I can't give accurate figures for the light output of my LED conversion. However the brightness of the red and blue are on a par with the HMI lamp, the green is about as bright but slightly less vibrant, and the white is noticeably bluer and slightly dimmer. Obviously I get no output at all from the UV filter :) Even though I removed one of the fans leaving the fan that sits under the ballast, my converted Miniscan is still a bit noisy. However I may be able to slow the fan down a bit as my LED runs practically stone-cold with the heatsink I'm using. While taking the photos I had both the HMI and LED minscans running for over half an hour. After turning them off the body of the HMI scanner was quite warm to the touch as you'd expect, but the heatsink on the LED wasn't even warm! I'm thinking that I may have over-specced the heatsink... The process of converting to LED obviously means that I can remove quite a lot of parts which in turn means that my LED Miniscan ends up being around 2-3kg lighter than the original Miniscan. The conversion to LED means I'm using around one tenth of the power that an HMI Miniscan uses. Result!

Thanks for all the nice comments. Progress has slowed a little bit as its far too cold to work out in the garage at the moment. I can get most of the wiring done today though as I can bring that into the house. The power supply still needs to find a home as it is slightly too big to fit under the lens/LED holder where the fan used to be. It may have to sit on its side next to the lenses. About 0mm :) Its a Roland PNC2300 desktop engraving/milling machine. While it would cut Aluminium, it will take until the end of time for it to complete anything. Its really meant for engraving/cutting foam, wood, modelling wax, and plastic. It will engrave onto Aluminium and Brass, but because its recommended engraving pitch (how deep it cuts on each pass) for metal is only 0.08mm and the cutting speed is 8mm/second, I wouldn't want to cut through a couple of millimetres of metal. As it is the plastic parts for my LED holder took about 5 hours to cut out, and the cutting pitch and speed are 0.2mm and 15mm/sec. respectively. If you want your own machine you could always buy either this Roland PNC 300 or this Roland PNC 2100 from G and M tools who are based in West Sussex. I bought my machine from them last year, and I keep half an eye on their website in case another machine comes up. I am tempted by the PNC 300 but I don't have the space, the money or, if I'm honest, the need at the moment for another CNC machine. If you wanted a machine to cut Aluminium then the PNC 300 is the best bet as its much stronger, although the cutting area is much smaller than my machine. The cheaper PNC2100 is the little brother to my machine. It will struggle to cut metal, but is perfect for plastic or milling your own PCBs.

Last week I mentioned that I was in the middle of building an LED conversion for my Clay Paky Miniscans. It isn't quite finished yet, but I thought I'd put a couple of photos so I can whet your appetites a bit and show you my progress so far. The idea to attempt this project came about when I tried fitting an old 100 Lumen Lamina LED into a broken Geni scanner to see what effect its condenser optics would have on the light output. I had previously tried the same LED in a simple 3 lens projection system I'd made, but the only thing I managed to project was an image of the individual LEDs within its die. When I tried the LED in the Geni I was expecting the same thing to happen, but I was pleasantly surprised to see that I got a nice even beam out of the fixture. Even gobo projection was nice and sharp. Encouraged by this, I found a 40 Watt LED on the Farnell website so I bought one to try in my Miniscan. I chose it because unlike other high-power LEDs, it can be run off a 24 volt power supply. Like a lot of other LEDs the one I chose is made up of several emitters on the same die, but they are wired up in two sets of six so each set of six needs 20-ish volts at 1 Amp. This does mean that I need two LED drivers, but I can use off-the-shelf drivers which makes things a bit easier. To hold it all together, rather than try to modify the lens mount in my Miniscans I decided to make a new replacement lens holder which would incorporate the LED, its heatsink, and the drivers. Heres a photo of all the parts for the holder after I'd cut them out on my CNC mill : http://i157.photobucket.com/albums/t41/gyro_gearloose/inthemill.jpg Once all the bits are bolted together they look something like this: http://i157.photobucket.com/albums/t41/gyro_gearloose/lensandheatsink.jpg The LED and drivers are missing from this photo as I need to buy a few more bits and pieces before I can wire it all up. The heatsink is a Thermalright CPU cooler. It doesn't have a fan of its own, partly because it sits directly over one already fitted to the Miniscan, and partly because if it did have its own fan I would need to find 12 volts to power it. The holder is designed to be a drop-in replacement for the Clay Paky lens holder so no modification is required. This means that if it doesn't work out at least I will be able to convert back to a discharge lamp.