Christmas in Brewster

Today I drilled out the holes on one of the heat sinks with a 5/32 bit. I also enlarged the holes on the bottom of it to accept a #10 screw. When I got home, I test fit the board back in the heat sink. The 6-32 x 3/8 screws with 1 #6 washer on the outside work great. All of the holes line up perfectly also. I’ll have to take pictures of my method of aligning the traics when I build the next board to post on here.

After the board was resting in the heat sink, I determined that I had 6mm between the PCB and the aluminum. While at the hardware today, I picked up a foot of 5/16″ OD, 3/16″ ID poly tubing with the intention of cutting it into standoffs. It fits snugly around #10 screws, which I thought I was going to use to attach the PCB to the heat sink, however the top holes on the Ren24 are too small for a #10 screw. I’ll have to pick up some #8 screws tomorrow, it seems like 1/2″ will work, but I might get some 3/4″ just in case. I can probably trim them if I have to. At any rate, I cut some 6mm pieces of the tubing and it looks like its going to work well as standoffs, at least for between the PCB and the aluminum. I’m not so sure how well it will work for between the heat sink and the enclosure, but I’ll deal with that when I get there.

I mentioned that I drilled out the holes on the bottom of the heat sink to accept #10 screws, but I don’t think I’m going to use them. I’ve got about 12mm to play with on both the top and bottom of the aluminum, so I think I’m going to put the mounting holes on the edges, so that I can attach the PCB, then insert the whole assembly into the enclosure and attach the assembly separately. If I use the supplied holes, I won’t be able to get to the holes once the PCB is in.

The plan for right now is to put screws right through the enclosure and into the heat sink to hold it down tight. I just have a feeling that if I tried to glue or epoxy something into the enclosure that it wouldn’t hold. I’m planning on putting silicone on the screw before I insert it into the enclosure on the outside to keep the water out, and I may put some epoxy on the inside to help keep it in place while the PCB/heat sink assembly isn’t in there. Probably should silicone over the screw too just to be safe. I haven’t figured out how I’m going to mount the enclosure yet, but I’m leaning towards using the knockouts that allow it to be mounted to a post using hose clamps. I haven’t quite figured out the water proofing part of that yet though.

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My Ren24 heat sinks arrived today. They look great! Only problem is that I ordered 6-32 stainless steel screws to attach it to the triacs, and the holes on the heat sink are made for smaller screws. My first thought was to go order smaller screws, it was recommended that I get 2-56 from here, so that there was some slop to play with. However, having spent as much as I already have, I couldn’t justify to myself spending another $30 (that includes shipping) on screws when I already have some. So, I will be drilling out the holes on the heat sinks. I tried a few test holes tonight, and already see I’ll have to file down where the bit tears out, or else the triac won’t make good contact with the aluminum.

Now that they’re here I can see the footprint they will utilize in the enclosures and I’m definitely glad I’m going with the 12×12 ones. I just wish I hadn’t ordered the 9×9 ones in the first place. I’m sure I can use them for something in the display though.

Next step is getting all the holes drilled out and then try and figure out a way to mount it in the enclosure. So far I’ve only assembled the one PCB because I wanted to make sure there wasn’t anything I needed to do different once I got the heat sinks and test fit it in an enclosure. It looks good so far, but I think I want to get an entire enclosure assembled before I continue.

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I’ve been anxiously awaiting my Pixel boards and in the mean time have been trying to figure out how to use them in my show. Isn’t that how you’re supposed to do it, buy first, figure out later. I’m leaning towards putting them in white buckets and putting them out like luminaries. I was originally wanting to do something like a PIC that JEC was using to create a stand alone show. I was hoping I could feed a DMX signal to the PIC and when it was getting a signal, it would just pass it on to the pixels. This way I could include the luminaries in the show, but when the DMX signal was absent (i.e. the show was over), the PIC aka standalone show, would take over and control the luminaries. One of the things I wanted them to do was flicker like a candle in a real luminary. So I set about trying to write assembler code that would do what I wanted. It wasn’t long before I determined it was going to be harder to do what I wanted. I still want to learn assembler and do stuff with the PIC, but this project seemed a bit big to take on right off the bat, especially considering I didn’t even have any Pixels to work with.

It dawned on me the other day when I was reading a blurb about Vixen’s background sequences and scripted sequences that I could probably do what I wanted from right within vixen. I found some code here and modified it to C# and to work with Vixen’s constraints (I wish vixen used 256 levels of dimming in scripts and not 100, perhaps I’ll post a feature request). I hooked it up to a string of multicolor LEDs and it doesn’t look bad. I will probably need to tweak it a bit once I get an actual pixel running off of it, but the concept seems to be there. I will also need to modify it to keep state for all the pixels, not just one. Anyhow, here is the code I’m working with right now.
[csharp]void Start() {
Random r = new Random();
int level = 0;
while(true) {
On(Channels(Channel_1), At(level), For(50).Milliseconds, Wait);
level += r.Next(-15, 16);
if (level > 90) {
level = 90;
}
if (level < 10) {
level = 10;
}
}
}[/csharp]

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So I’ve been promising pictures, and I finally thought I would spend some time trying to figure out why I haven’t been able to get things working the way I want using Picasa Web Albums to store my pics and just display them here. It turns out it has absolutely nothing to do with Picasa. It also has nothing to do with the WordPress plugin I’m using to generate the html to display the pictures, nor does it have anything to do with the plugin I’m using to display the pictures using lightbox (slimbox).

The problem I was having (I thought) was that when I added multiple pictures to a post, I would get into a redirect loop when trying to view that post. At the time I started trying to post pictures, I had just finished my DMX Dongle, so that was one picture I was trying to include, and every time since, I’ve also tried including this picture. Well tonight, I just randomly selected two pictures from an album and having two pictures worked. I thought that was odd, and created a post with just the DMX Dongle picture and I got the same looping behavior. So that narrowed the problem down to that picture which made no sense. I started examining the HTML that was being generated for that picture and found nothing out of the ordinary. So I just started removing parameter values from the HTML code until the loop went away.

I eventually narrowed it down to removing the title of the picture (which was also the img alt text) and the picture worked fine. Very odd, since the title was only “Lynx DMX Dongle” (I’m using HTML character codes to display that text, you’ll see why shortly). I started changing the text and found that all those words worked fine on their own, but Lynx[space] did not work. I then tried creating a post with just the text “Lynx[space]” and sure enough, got the redirect loop. It happens if the L is lowercase also.

So there must be some funky juju regexp somewhere that is picking up that text and causing the redirect loop. I plan on digging into the code sometime, but I’m not sure when I’ll get around to it.

Anyhow, I should have pictures available soon!!!

EDIT:
Just tried to add a picture with the title “The Lynx DMX Dongle PCB in its case”, sure enough… redirect loop! Took out the Lynx[space], no problems!

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Well I started out the day by taking my Ren24 to work with me to verify that the problems weren’t limited to my USB->RS232 Adapter. So I plugged it into my work machine with a built in serial port and I was still getting the framing errors. So I knew it wasn’t the port. After the kids and April went to bed, I made a new DB9->RJ45 Adapter, no dice. I lowered the baud rate in the firmware and recompiled, changed all my settings and I still got framing errors. Just out of a whim I tried plugging my Hexin RS232->RS485 adapter in and made a quick cable and low and behold, I had communication with NO FRAMING ERRORS!!! So I thought I was home free. I flashed the pics with the actual firmware and tried it with a sequence one last time before I put the optos in. The LEDs weren’t lighting up and that’s when I realized I forgot to turn on the PWM flag in the firmware. So off to turn that on, recompile and pull the PICS and reflash them. So I put them back in and this time, LEDs lighting up like they were supposed to. So I popped all the optos in and hooked up channel 1, fired it up and…. nothing. Tried channel 2… still nothing. Ok, so the LEDs were lighting but not firing the optos or the triacs. I looked the board over again and caught glimse of the notch on the silkscreen for the optos on channels 1-12…. here it is opposite of 13-24. I put all the sockets in the same way, so channels 1-12 were all backwards. Fortunately I could just reverse the optos and no damage was done. Fired it up again, and… success We have dimming lights!!! Now if I can remember that the sockets are backwards if I ever have to replace an opto.

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I got my first Ren24 built up tonight (well last night since its past midnight… again!). I powered it up with no problems, and then I programmed one of the PICs with the diagnostic code. The heartbeat and zero crossing indicators were functioning as intended, but when I tried to send a sequence to the board, both the COMM OK (which is supposed to indicate no framing errors) and the Framing Error indicators were lighting up. I’m not quite sure what to make of that. I posted a question to the group and I’m going to bed before I undo all of my hard work.

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My Ren24 boards did arrive today. After we got home from my Cousin’s wedding, I spent some time on the first one. I got all the resistors, diodes and sockets soldered in. I spent some time trying to figure out which diodes to put in, because WakeFan gave us both options, the 2 5239B’s on the BOM, or 1 5239 and 1 5229 which was spec’ed out for when you are using the board with RS232. While there was some talk that the boards would be fine with the 2 5239′s, it seemed that the safest way was to go with the 1 5239 and 1 5229, because, while I won’t be running RS232 during the display, I will be using it to test the board and to make sure the RS485 converter is working, should I have any problems with it. I went ahead and put the 120 ohm terminating resistor in also. It says to leave it out if you are using the DMX firmware, which I ultimately want to, but for now I will leave it as is and see if I can just get the thing working.

I would love to keep going, but I’m going to call it a night though, which is probably for the better because my eyes are starting to hurt and I’ll probably make some silly mistake if I keep on going. Hopefully tomorrow I’ll have some time to finish populating it.

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