Archive for the ‘DMX’ Category

Now we’re dimming!

Tuesday, February 24th, 2009

My DMX dongle PCBs arrived today. I was rather excited to get one soldered up so I could test out my DMX Grinch Controller. It only took about an hour to solder it up, quite a testament to RJ’s design. Anyhow, I plugged it in, fiddled around with some settings and voila, I had [smoothly] dimming lights. I guess now I’ve got blinky, flashy, dimmy. They definately look a lot better when dimming. I’m so glad I went with the renards so that my whole display can dim. When I signed up for the renard coop, I had very little knowledge about what I was getting myself into, but I think they will end up being a good decision. I kind of wish I had gone with something that spoke DMX natively, but the renards are supposed to speak DMX with different firmware, so I might have my cake and eat it too!

My whole Grinch setup minus the SSRs

More dimming than last time, but still not quite there.

Thursday, February 19th, 2009

As promised, I threw a MAX485 on a bread board and hooked it up to my Arduino. You can use the USB driver on the Arduino board and hook the TX pin into the Arduino, combined with the Entec Open USB DMX driver, you can easily and cheaply spit out DMX. Anyhoo, I hooked that circuit up to my Grinch DMX Dimmer and fired up Vixen and started spitting out some dimming channels. Indeed I had some dimming Christmas lights, but it was very jumpy and there was some random flashing going on. It surely wasn’t smooth, but at least it proved that my DMX Dimmer was getting a signal. I’ve been reading that the Open DMX (which has no “brains”) has a hard time keeping up with the timing for the DMX signal (like .4us) because the computer is doing all the work. I’m hoping that when my DMX Dongle PCB gets here and I get it built up, I will have much better results. It will have a dedicated controller for keeping the timing just right and the computer will just have to say “hey you, turn on channel 1 at 50%”, and it’ll politely do so.

I put together another SSR, and had much better success this time, maybe I’m actually getting the hang of this soldering thing. I had two of the triac joints bridged, but that was easy enough to fix and at least I didn’t fry anything this time. I still have 14 more to build, but I’m not in a huge hurry. The Grinch and SSRs will probably end up at the store anyhow, as I should have enough channels (for this year) with my Ren24’s. Speaking of which, the PCB’s are supposed to be arriving Friday, so hopefully I’ll have mine next week. The heat sinks are due in March 2nd, so by mid march I would imagine I would have at least one running and in its enclosure that I can post some pics. I found a bigger enclosure than the 9×9 ones I was going to use, it should let me have more room to play with for putting a grounding bar in and some strain reliefs in.

Most of this week so far I’ve been trying to teach myself Assembler on the PIC so I can use one as a standalone show controller, (and perhaps for other projects… cough… cough… wireless barcode scanner). I have been able to send data to my ShiftBrites for now, but am trying to figure out the best way to put a “show” on there. At least it’s progress I suppose. I’ve also been trying to find music that I like and that will be appropriate for my show. I’m also trying to get a feel for the beats and what would look good with it. I probably won’t start sequencing until I nail down the layout of everything, and that won’t happen until it warms up enough to measure out parts of the house. I hope to get going on sequencing soon though, because from what I have read, it takes most people 4 to 5 hours+ per song, and that’s if you know what you’re doing.

Dimming Grinch… Sortof

Monday, February 9th, 2009

I got my Dimming Grinch DMX board assembled last night. The backordered terminal blocks finally arrived from mouser last week. I got it all together and checked it over for bad joints and powered it up. Right off the bat, the LEDs were acting really flaky. They would come on and go off randomly. It also seemed that when I would touch certain places on the board they would react to that. I thought great, I’ve got a bad joint somewhere or a broken trace. I couldn’t find anything. Turns out that because they are connected to the AVR and it hasn’t been programed yet, the pins are set as inputs as the default. Being inputs, they were just turning the LEDs on willy-nilly and can be influenced by outside electrical noise, which apparently is what my body was inducing when I would touch the board.

Anyhow, when I tried to program the chip with my usbtinyisp, I got nothing. I screwed around with it for a while, and eventually built up a programming circuit on a breadboard to try it out outside of the PCB. Sure enough, first try, the programmer found the chip. OK great, I went to set the fuses and got the lower fuse set fine. When I tried to set the higher fuse, nothing. I couldn’t find the chip again. Well since I had set the chip to use an external clock when setting the lower fuse, it was expecting an external clock and my circuit didn’t have one. So back to the PCB I went, because it has an external clock. I screwed around with it for a while and ultimately gave up. Today after reading the schematic, I realized that pin two of the ICSP header wasn’t connected to anything and since pin two is where the chip gets Vcc from the programmer, I knew I wasn’t going to fry anything if I left the programmer’s self powered jumper on. I tried it and BAM! it worked.

I’m thinking that when I removed the header, neither Vcc nor ground was getting connected, and the grounds needed tied together to make the circuit and the programmer “become one”. So, I got the fuses reprogrammed and flashed the program onto it and we appear to have one working dimming grinch DMX board thingy. Only missing part is the DMX. I’m planning tomorrow night to hook a max485 to my arduino to make a pseudo DMX dongle that I can at least test my dimmer with.

I might just have dimming Christmas lights tomorrow night and my Ren24’s aren’t even here yet!

Robert Martin's Dimming Grinch DMX Controller