NickLee Posted July 18, 2003 Share Posted July 18, 2003 http://ele.tut.fi:/~viikari/http://users.skynet.be/kristofnys/ Link to comment Share on other sites More sharing options...
Brian Posted July 18, 2003 Share Posted July 18, 2003 A couple of people asked me for a copy of the 480 channel interface, to save my e-mail bandwidth (the file is 2.5 megs) it can now be found here... Click here for DMX interface you can, of course, use right click to save it to your PC. Link to comment Share on other sites More sharing options...
Ketil B Posted July 18, 2003 Share Posted July 18, 2003 [WARNING] - possible commercial post coming upthis woud be good if you can do USB to DMX on a Mac runing OS X (10.2) Link to comment Share on other sites More sharing options...
Brian Posted July 19, 2003 Share Posted July 19, 2003 this woud be good if you can do USB to DMX on a Mac runing OS X (10.2) It should be possible. The USB interface chips I use have manufacturer supplied drivers for...Win98/98SE/2000/ME/XPMac OS-8/OS-9/OS-XLinux/Open BSD/Free BSD though only being a windows type I haven't tested the others. I was going to implement a simple ASCII protocol so the 'dongle' could be controlled from something as hyperterminal for testing and driven from Visual Basic/C/Whatever if anyone wanted to write their own code. Link to comment Share on other sites More sharing options...
techwsussex Posted July 27, 2003 Share Posted July 27, 2003 I think the Maplin blurb says it all: "Control disco lighting equipment from your PC" since when were we into controlling disco lights? Owen Link to comment Share on other sites More sharing options...
simon-carter Posted August 28, 2003 Share Posted August 28, 2003 Brian wrote:Not anymore. 1 chip and free drivers on the PC which makes the far end look like a serial port which will run at up to 3 Mbps (DMX is only 250kbps).Can you give details of the chip / PC driver - this would be really helpful to me in a completely different project requiring USB. Thanks Simon Link to comment Share on other sites More sharing options...
martinw Posted August 28, 2003 Share Posted August 28, 2003 I think these are the devices Brian is refering to: FTDI They look like they will do DMX without too much trouble, although I've not actually tried them. Dontronics in Australia make cheap development boards with the chips mounted, so you don't have to do any surface mount stuff, and they ship to the UK. Martin Link to comment Share on other sites More sharing options...
Brian Posted August 28, 2003 Share Posted August 28, 2003 FTDI are the chips I use, though it's not easy to make DMX with them. The tricky bit with DMX is making the start of frame 'break' signal. You can get them mounted up on modules here in the UK at £25 each excl VAT from FTDIs UK distributor. Link to comment Share on other sites More sharing options...
martinw Posted August 28, 2003 Share Posted August 28, 2003 FTDI are the chips I use, though it's not easy to make DMX with them. The tricky bit with DMX is making the start of frame 'break' signal. Can you make them do this internally or did you end up gating the output with one of the IO pins, I've had to do this on a few microcontroller UARTs I've implemented DMX on. Did you write your own driver for DMX or use the FTDI virtual com port or the direct driver ? Do they let you add an interbyte time (or extra stop bits beyond the normal 2) when using the transmit fifo? I frequently come across cheap fixtures that can't accept DMX at the maximum transmission rate, and need something a bit more mellow.... Did you do DMX input as well as output? Martin Link to comment Share on other sites More sharing options...
Brian Posted August 29, 2003 Share Posted August 29, 2003 Hi Martin check your e-mail. Link to comment Share on other sites More sharing options...
Tomo Posted September 3, 2003 Share Posted September 3, 2003 FTDI are the chips I use, though it's not easy to make DMX with them. The tricky bit with DMX is making the start of frame 'break' signal. Can you make them do this internally or did you end up gating the output with one of the IO pins, I've had to do this on a few microcontroller UARTs I've implemented DMX on. You can do this internally using the Microchip PIC series of microcontrollers.(Please note - I've never actually done this, just worked out the theory) Several PICs have built-in UARTs, which you can use to send the DMX signal at the correct baud etc. However, the pins they use can also be used as normal input/output pins, so all you do is turn the UART off internally and set the pin to the BREAK level. The more interesting bit is that the PIC UARTs all work at logic level, and DMX 512 is a differential protocol (like RS232 and RS485) so you'll also need a line driver. The MAX23x series will probably do the trick. Link to comment Share on other sites More sharing options...
martinw Posted September 4, 2003 Share Posted September 4, 2003 The more interesting bit is that the PIC UARTs all work at logic level, and DMX 512 is a differential protocol (like RS232 and RS485) so you'll also need a line driver. The MAX23x series will probably do the trick. RS232 is not a differential protocol, unlike RS485 on which DMX is based. Most DMX transmitters/receivers use a device such as MAX485 or SN75176 as a line interface. You can do this internally using the Microchip PIC series of microcontrollers. I've done several DMX transmitters and receivers using PICs, and they are pretty easy to use for this task, once you get used to their architecture. Their biggest strength is their availability in small quantities from many different sources. Martin Link to comment Share on other sites More sharing options...
Tomo Posted September 4, 2003 Share Posted September 4, 2003 Whoops, you are indeed correct.Just checked, and RS232 uses -5 to -15v for data '1' and +5 to +15v for data '0'Not actually differential, but sounds like it. Link to comment Share on other sites More sharing options...
TomLyall Posted February 19, 2004 Share Posted February 19, 2004 If anyones interested... the datasheet for the maplin DMX interface is here... http://www.milinst.com/gemodules/1_463.pdf you can also find the freeware control softwear on their website, obviously doesnt do anything without the interface but its good for seeing what your gonna be able to do, of course it comes with the source code so you can adapt it anyway It does 112 channels out from a serial interface, or 4 from the analogue inputs (start address can be from 1 to 118) not too sure on its recieving capabilities (didnt read it, doesnt interest me), but I think it'll do four analogue 0-5v outputs. im thinking of buying one, probs butchering it and putting it in a rack mount chassis, at least then I can put 5 pin XLRs on it then! :** laughs out loud **: might build a power supply into it too *begins muttering to self* Tom --Edit--- Also might be worth knowing, if you gonna buy the one from maplin, you can save yourself about £15 by buying direct from the company that makes them.http://www.milinst.com Link to comment Share on other sites More sharing options...
Brian Posted February 19, 2004 Share Posted February 19, 2004 im thinking of buying one, probs butchering it and putting it in a rack mount chassis, at least then I can put 5 pin XLRs on it then! might build a power supply into it too *begins muttering to self*You may as well buy one like this for £130. Link to comment Share on other sites More sharing options...
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