#101  
Old 17-07-2016, 03:21 PM
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By the way, I made a quick draft of the front 3D-printed plastic part, based on Faddy's images.

Dimensions are just a guess as nothing is know yet but I have to print it first, figure out the printed dimension for the sensor step and adjust the model for the plastic shrinkage.

I will need to get my sensor out of my D40 soon...
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  #102  
Old 17-07-2016, 03:53 PM
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Normally when building stuff like this I would use a female connector on the cable as it carries power and it is more difficult to short compared to pin connector......
Yep totally agree. If we wanted we could use a breakout sub-PCB like Faddy. This would allow us to use a DB9 on the rear of the camera that mates with another DB9 (opposite gender) outside the case, connected to USB/Power connectors etc. Mount it all in a small plastic case. This will allow use to seal the case yet route proper USB/Power to the camera with proper connectors.

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Off-topic question, have you "freed" your sensor from the aluminium holder yet? I just noticed on Martin Raabe's page (your link few posts up) that he machined the aluminium to get the sensor out.
I have another D70 coming, I'll do them both at once. I'll have to get some DMSO. I did laugh at Martin Raabes method of getting the alloy holder off. I was thinking...no way...but...he's obviously not only practical he's damn 1st class at everything he touches, so the laugh is definitely on me. I also noted he included a sensor PCB jackscrew arrangement for sensor orthogonality, but I also guess he had micrometer dial gauges to set this all up.

Gary asked ..."why Faddy used the plastic sensor cover"...really I had to say...I'm not sure!
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  #103  
Old 17-07-2016, 04:05 PM
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Are you still following the CN thread? Filip Lolic is another person of great skill, see his build here. No plastic in front of the sensor.
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  #104  
Old 17-07-2016, 04:29 PM
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One use of the plastic in front of the sensor would be to locate the sensor in the centre of the window. But the PCB should already be doing that.
Another use I can think of is to keep it parallel with the window. The sensor is socketed so keeping it "flat" by pushing it all the way in may not work too well.
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  #105  
Old 17-07-2016, 06:45 PM
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Are you still following the CN thread? Filip Lolic is another person of great skill, see his build here. No plastic in front of the sensor.
Sure am...gazed upon his case with envy eyes. Which I had lather and mill...errr and skills to operate them!

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One use of the plastic in front of the sensor would be to locate the sensor in the centre of the window. But the PCB should already be doing that.
Another use I can think of is to keep it parallel with the window. The sensor is socketed so keeping it "flat" by pushing it all the way in may not work too well.
Yes this is what I was thinking. The PCB keeps the sensor at centre. Would be nice to have PCB metal standoffs near this to keep the sensor absolutely still and square.
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  #106  
Old 17-07-2016, 09:07 PM
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Have you seen this already?
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  #107  
Old 18-07-2016, 09:54 AM
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Unfortunately yes... with desire.

Flolics machining is excellent. Doesn't look like he sealed the sensor area...probably impossible with the sensor pins and socket. His case is designed to accommodate connectors, silica gel plug etc.

edit:
looks like he has some youtube vids of making his enclosure.

Last edited by wasyoungonce; 18-07-2016 at 10:50 AM.
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  #108  
Old 18-07-2016, 11:29 AM
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Lesson of the day: don't type a reply in a window that you left open the whole night... you will get "token expired" and have to retype everything.

Anyway, the main reason I mentioned Filip's latest images is that I believe that his sensor holder will be spring loaded and not for us to start drooling over it

Faddy's design relies on accurate distance between the PCB and the 3D printed piece, also including how deep the sensor goes into the socket.

Spring loaded sounds like a better idea and that piece should be easily printable. Not sure how Filip is dealing with the sensor alignment though...
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  #109  
Old 18-07-2016, 02:33 PM
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I think he spring loaded the sensor cap to allow contraction, expansion. He probably should have use qty 3 or 4 spring mounts. Maybe even and adjustable spring load...that also adj's camera tilt? Like a spring loaded jackscrew
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  #110  
Old 18-07-2016, 11:15 PM
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You probably already knew but I just found out that the source code of the Ascom drivers for the Cam8x builds is actually available. Not sure if we want to play with that...
The microcontroller firmware does not seem to be available.
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  #111  
Old 20-07-2016, 05:54 PM
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Hi Luka

ASCOM driver (object interface) is all open development ...to make it compatible. Gotta love how ASCOM has swept to popular use since inception.

I noted how grim has his cam86 up and running. He reversed the PCB case/lid so the sensor faces the lid. No images of the TEC or TEC HSF but you can see he routed wires to the TEC. Also out the crystal on the bottom PCB layer...so he is still "fiddling".

It appears he used a microphone type connector on the camera base, with what looks like a plate and seal.

I'm still doing the Cam86 PCB. Had an error on my schematic that wouldn't let me open it today...I managed to open one of the backups, thankfully. Only lost 2 hrs work. The Schematic and PCB do have differences. No idea how it got this way, the PCB appears to be correct, not the schematic.

I'll be around another week on this at least before it's close.

Oh received my 2nd D70 so I'll be pulling them apart for the sensors soon. I have a D70s and D70.
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  #112  
Old 20-07-2016, 06:09 PM
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Altronics/Jaycar have a whole bunch of waterproof connectors that would fit inside the case on the side, like Grim did.
Something like this? 2A per pin only though.

edit:
Probably even something like this would fit. 5A per pin, 6 pins. Quite big.

On the other hand, this D-sub connector has 5A rating, according to the data sheet. I assume per pin???

Last edited by luka; 20-07-2016 at 06:23 PM.
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  #113  
Old 20-07-2016, 07:00 PM
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Yes that current rating will be per pin. Probably over optimistic though. The only issue is we need to take this plug to a breakout board like Faddys as there is no such thing as sealed USB sockets, as we know.

Interesting in that Flolic on CN didn't seal his sensor area more like left vents. I wonder what's his thinking on this.

The Cam86 board is coming along slowly. There are a few errors or parts not numbered or miss-numbered. Still its a much better iteration of the original.
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  #114  
Old 20-07-2016, 09:00 PM
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We can always use multiple pins to get more current into the box if needed. D sub connector will have quite a few spare pins.

There exists one completely sealed USB socket at Altronics that I know of but it is quite bulky. It would probably fit... just... with the latest inverse PCB orientation.

I can see a possible problem with the new inverted PCB design and the alignment of the sensor. Unless the lid is tightened metal-to-metal the alignment will change every time the camera is opened. I don't have any diecast boxes here to check, do you know if the lids get tightened all the way?

I keep thinking if it would be possible to use the 4 screws which hold the PCB to change the PCB and hence the sensor alignment. Drill the holes through, and then spring-load the PCB somehow... not sure how... but the idea was to turn the screws from the outside to change the alignment of the PCB and hence the sensor.

Looking at Filip's design, I think he will seal the sensor area. The red plate that the peltier sits on has only cutouts for the posts for the feet from the sensor to go through. A bit of silastic around the posts will seal this nicely. I think I saw somewhere that he is using multiple stacked posts to gain height (and reduce heat transfer?). This way he will even be able to leave one row of posts glued in while being able to separate the PCB from them.
Then there is something that looks like an orange seal around the Peltier.

Here is a question. If the whole box is sealed and moisture inside controlled carefully (dry gas and desiccant and possibly a humidity sensor), is there any need to keep the sensor in a separate dry chamber?

This is an interesting post about the sensor temperatures, in particular see Richard's comments and PDF. HQY8 has the same sensor as we are using.
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  #115  
Old 21-07-2016, 06:03 AM
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Hi all, Filip from "the other" forum here
I just want to clear few things regarding design of my camera housing. First, sensor will be sealed in it's own chamber. This is not the easiest thing to do, but it is certainly the best thing to do if we think about moisture control and possible condensation problems. Air volume in that chamber is quite small (comparing to other design possibility to seal complete electronics). Plus I will fill the chamber with dry Argon gas and include some small piece of desiccant sheet.
Connection between CCD and PCB is via few stacked sockets, with one of them glued to aluminium bracket that will provide mechanical support and sealing (with additional O-ring).

Ok, let me just include few images for you to see what I am talking about

CCD socket (with sealing)
https://dl.dropboxusercontent.com/u/...ccd_socket.jpg

https://dl.dropboxusercontent.com/u/...cd_socket1.jpg

This is how CCD will be connected, with individual pins to reduce thermal transfer. Plastic cup over the sensor will keep it pressed onto the TEC module and centered in the chamber.
(please ignore the greasy fingerprints )
https://dl.dropboxusercontent.com/u/...cd_socket2.jpg
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  #116  
Old 21-07-2016, 08:27 AM
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Hi Filip, welcome to "this" forum
I hope we will see more of your posts in the future

Last edited by bojan; 21-07-2016 at 11:43 AM.
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  #117  
Old 21-07-2016, 09:59 AM
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Hi Filip,

a warm welcome to "downunder". We have been admiring your work but couldn't completely understand "sealing" until you posted the above images. Now we get it "a picture tells all"! Good idea, pot SIL connectors in a sensor mount housing. Double stack them for TEC clearance! Wish I could think of things like this.

You then only have to worry about moisture in the sensor chamber! This is the problem with us atm. Using the enclosure the grim and others used. Its really not the best solution.

I suspect we will stay with this till we get some cameras "running" then push ahead to a different housing. I say this with eyes of envy towards your set-up!

Keep up the good work.

Luka, I can add stand-offs to my PCB board drawing, easy as. But I think it would be difficult to hve this as a jackscrew arrangement to adjust from outside the box. Impossible to seal this.

If the box is sealed and flushed with gas then this enough for the sensor. No separate chamber needed. This is the beauty of Filips' enclosure. A small sealed chamber is easier to control than a bigger volume. I have some doubts the case we are using is fit for this (sealing). Sorry to say.

On another note....my eagle PCB files got corrupted late last night. Wouldn't open, gave errors ..."not consistent" and "wrong technology... at line xxx" blah blah. After hrs and hrs...and a sleep..found Eagle has an editor I can use to goto the line, delete the "technology" field save...voliÓ. It lives and re-linked back to the board!
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  #118  
Old 21-07-2016, 11:39 AM
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Hi Filip

I have seen your name crop up on several forums and I was always impressed with your work
Thank you for the explanation, ideas and photos


Brendan, as I said, I keep thinking about the jackscrew arrangement but cannot figure out how to do it. Anyway, good work with Eagle, but don't forget to keep making backups.

How will we actually mount our Peltier? One side to sensor and the other to enclosure (with copper inbetween to fill the space)?

When you say the box will not seal, are you talking about the seal between the lid and the base? We could run a thin layer of silastic on the outside after everything is screwed down. Not the best look but it will do the job
Or even squeeze some into the gap where the rubber seal is. It will look nicer but it will be more difficult to take the camera apart.


Regarding the moisture control, what if we keep everything (sensor + electronics) in one chamber, fill it with Argon and silica gel packs. The moisture levels will be quite low. Then we could add a humidity sensor inside the box with one wire going outside to a small display which shows the humidity inside the box. This will show when refills are needed.

Or we could copy Filip's approach, get a piece 3D printed (or milled) that screws into the existing PCB posts and has a large rubber o-ring which will seal the sensor enclosure. We could also glue the extension sensor posts, just like Filip did.
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  #119  
Old 21-07-2016, 12:11 PM
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Quote:
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How will we actually mount our Peltier? One side to sensor and the other to enclosure (with copper inbetween to fill the space)?
Gary has this covered, a slug of copper between the rear HSF and TEC. The rear HSF mounted on rear case and sealed to it. Of course the distances to Sensor etc have to be reasonably precise.

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When you say the box will not seal, are you talking about the seal between the lid and the base? We could run a thin layer of silastic on the outside after everything is screwed down.
Just a little dubious of sealing capabilities of the box. Its not exactly machined quality! I've seen air leaks thru pins of connectors ...tiny very slow bubbles but more than enough wreak havoc. A perfect seal is probably not achievable with the case IMHO. We can probably get it well sealed but intrinsically its not something ever designed for sealing like this. This doesn't mean it won't work...obviously it does, proof seen in other builds.

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We could run a thin layer of silastic on the outside after everything is screwed down. Or even squeeze some into the gap where the rubber seal is. It will look nicer but it will be more difficult to take the camera apart.
Yes some silastics seal ok when run in thin beads, especially between mating surfaces screwed down. The case comes with a seal, neoprene or such like.

Quote:
Originally Posted by luka View Post
Regarding the moisture control, what if we keep everything (sensor + electronics) in one chamber, fill it with Argon and silica gel packs. The moisture levels will be quite low. Then we could add a humidity sensor inside the box with one wire going outside to a small display which shows the humidity inside the box. This will show when refills are needed..
Yes this is the plan, seal it all, as discussed we might run into issues as we need a purge port (which we looked at with silica gel), which is probably right on the limit of fitting the case.

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Or we could copy Filip's approach, get a piece 3D printed (or milled) that screws into the existing PCB posts and has a large rubber o-ring which will seal the sensor enclosure. We could also glue the extension sensor posts, just like Filip did.
I think the original designers looked at this and decided its much cheaper and easier to try a "sealed case". Which is what we need, a cheap easy approach. Thus sticking with a case approach, with a purge port and sealed connector is out best bet. Seal the rear HSF and front nose piece to the case with a thin silastic bead. The connector is sealed, the purge port can be the silica gel ports we looked at.

We assemble the unit, leave open the purge port, soak it in Argon in a plastic bag, open bag seal the port...done. When you open the plastic bag keep its opening upright (Argon being denser than air) we can keep the item reasonably filled with Argon as we screw in the port. Of course we can leave the port in the bag and probably start screwing it in wile still sealed.
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Old 21-07-2016, 05:49 PM
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Slowly getting the board done...one bugger up at a time. Finally now doing trace laying...the difficult part! Manual routing FTW!
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