All Sky Camera Revisited

[Gina]

Latest version of the reservoir.

[Gina]

Wasn't getting very good results with the 0.8mm nozzle and 2.85mm filament so swapped hotends to the 0.4mm nozzle and 1.75mm filament version.  Then for better interlayer adhesion to ensure a watertight reservoir, I went for PETG.  The reservoir is now printing nicely though taking a while.  Interchangeable hotends certainly helps.  My thanks to @Chriske for that idea.

Edited October 27, 2019 by Gina

[Gina]

Finished and cooling.

[tekkydave]

When I was using both 3mm and 1.75mm filaments I did interchangeability by swapping the front of the Titan Aero. You need 2 fronts and complete heatbreak, block, heater, thermistor & nozzle assemblies. All the wires need inline connectors too but it can be switched in a couple of minutes.

[Gina]

My interchangeable hot ends consist of Precision Piezo Z probe unit, cooler, heater block with heater and thermistor plus 4 wire connections.  To swap I remove the 4 screws from the front of the E3D Titan extruder and swap hotend plus filament guide.  Not quite as easy as Chris's system but best I could manage with what I have.

[Chriske]

So Dave you did about the same as we do.
In my case it takes me about one minute to swap hotends and/or filament.

These are only a few of what I made.
They all E3D-V6 clones. Except for the silicone socks, I make all the parts of all hotends myself. Only for the bigger nozzles(above 1.5mm) I make my own silicone socks.

 

This is a Volcano with a 1.5mm nozzle. I used this one for my 2meter high SaturnV rockets.
All hotends always use the same cooling fan, that is why the external connector. The cooling-fan clicks over the heatsink.

 

Connection of heater, PT100 and partscooling-fan is done internally with small selfmade PCB's/connectors. To be on the save side I use two connectors(right side) for the heater only.
Just two M3 bolts are needed to hold all well centered and connected. All hotends are exact copies. So all hotends for all my printers (and friends who have built the same printer) are interchangeable very handy. On the PCB is marked NTC, but we all use PT100 instead.

Edited October 28, 2019 by Chriske

[Gina]

Now have the water cooling system set up on the table and running a test.  Ambient temperature 18°C.

[Gina]

Camera sensor temperature now 1°C.  Peltier TEC is drawing 2.6A at 13.8v.

Edited October 28, 2019 by Gina

[tekkydave]

2 hours ago, Gina said:

My interchangeable hot ends consist of Precision Piezo Z probe unit, cooler, heater block with heater and thermistor plus 4 wire connections.  To swap I remove the 4 screws from the front of the E3D Titan extruder and swap hotend plus filament guide.  Not quite as easy as Chris's system but best I could manage with what I have.

My piezo is embedded in the motor mount so I didn't have to worry about that bit fortunately. I use 1.75mm exclusively now so no more swapping about

 

[Gina]

Yes, I plan to go for 1.75mm filament except for my Giant printer which will be using 2.85mm.  Next colorFabb sale I shall buy more 1.75mm filament, PLA and PETG white.

The other reason for interchangeable nozzles is to be able to change nozzle size without messing about with a hot block to change nozzles.

Edited October 28, 2019 by Gina

[Gina]

Returning to camera cooling, the water cooling is not working as well as the fan and Artic big heatsink but with nearly 20°C below ambient of cooling I think it should be adequate and no need to cut a big hole in the side of the ROR.

[Gina]

The water in the reservoir is tepid so several degrees above ambient and I could make the cooling better with a 120mm radiator and fan.  I have both but the smaller radiator is easier to fit inside the ROR.  I'll try that and upgrade to the bigger one if wanted.

[Gina]

Water cooling might seem OTT but it's much easier that blowing air out of the observatory up to the ASC.  Just a couple of small pipes to go from inside to outside and there's already a gap under the barge boards where they can go.  Also, it makes the enclosure much easier to seal to keep damp out.

[Gina]

I think I'm going to have to change my mind about putting the ASC on the south side of the roof due to lack of accessibility.  (Ladder on soft mud!!)  Think I shall have to go back to the aluminium pipe on the north side attached to the wall of the observatory.  In other words, ASC on top of mast which can be lifted up from the ground without needing a ladder.

[Gina]

I have been experimenting again with 3D printing a waterproof housing and have succeeded.

[Gina]

I've ordered a smaller acrylic dome (80mm) which I think will be easier to fit.  I also have a more suitable waterblock for the cooling.  With the possibility of DSO imaging seemingly improving I could do with the ASC back in action.

Edited January 14, 2020 by Gina

[Gina]

Update.  Case with camera assembly and thermal jacket.  Lid with hole for lens and dew heater in position.  The space on the left will take the RPi with HAT and buck converter for the 5v RPi power.

Dome placed on lid.

Bottom view with waterblock.

[Gina]

Still haven't quite decided to go for a mono or colour camera.  The colour camera will need the broken USB connector replaced or bypassed.

[Gina]

I've managed to get the colour camera apart by destroying the ST4 connector.  I can do he same mod I did on the ASI120 that had a broken USB connector - solder on a USB cable to the USB2 connections inside the camera, running the cable out through the hole where the ST4 connector was. 

I think I would prefer a colour image from the ASC.  Colour seems to be the consensus of opinion amongst ASC users.

[Gina]

Screenshot of the relevant parts of datasheet for a USB3 PCB connector as used in the camera.  I only need to connect to the USB2 part as the RPi 3B is USB2 only.

USB2 wire colours.

[Gina]

The job in pictures :-

This is the broken USB3 connector.  The centre spigot on the connector has broken off leaving the USB2 connections floating.

A USB2 cable cut and stripped and the wires fed through one of the holes where the removed ST4 connector was fixed.  Fixed in placed with hot-melt glue.

Wires stripped and soldered to the USB2 connections.

Main PCB fitted back in case.

Sensor PCB and Main PCB screwed back into case and sensor reconnected.

[DaveL59]

nicely done Gina

Could you perhaps not fit a strain relief grommet on the cable too, so as not to have a future mishap? No idea on the size of the ST4 socket but perhaps one like this:

https://www.amazon.co.uk/sourcingmap-Strain-Relief-Grommet-Diameter/dp/B078HM4ZB8/ref=sr_1_fkmr2_1?dchild=1&keywords=split+cable+grommet+strain&qid=1588686176&sr=8-1-fkmr2

 

[Gina]

Now the "nail biting" part - testing...

[Gina]

Hmmm...  Not working.  I'll investigate.

[DaveL59]

fingers crossed for NO magic smoke escaping