Gina

Cutting pattern for the plywood.

Filament spool in bottom of box. It will be supported on a centre spindle running on ball bearings and central axle.

Drive belts and bed.

I'm going to try a smaller box and see how that goes. This is using the length of round rods I have on order which can be attached to the sliders with 3D printed brackets.

I've ordered the other 5 for my Mini printer - 2 each for X, Y and Z. I'm having "fun" designing it all in CAD software - big job! Blog.

Sliders for X and Y rails added. So far this is just a small number of the many parts involved in this 3D printer but I think a CAD model is worth drawing to fit all the parts together.

Assembly top view showing box, X and Y rails plus crossed rods that carry the extruder and hotend etc.

The linear rail and runner seem excellent so I've ordered 5 more, making 2 each X, Y and Z rails. I also have X and Y drive rods and the crossed extruder and hotend rails on order. See Blog for my Mk2 Mini 3D Printer.

The piece of hardwood ply I bought for the job is 900mm x 900mm x 18mm. To allow room for motors, brackets etc. I reckon to add 50mm at each end of the XY rails. So that makes 400mm x 400mm inside and about 440mm x 440mm outside. This is the sort of box I'm thinking of with a height of just under 450mm. This should give a print volume of 190mm x 190mm x 220mm approximately using 6 off 300mm MGN12 rails. The bottom front rail will come from the bottom panel and the top a piece of ply left over from my Concorde printer box.

Yes, they are suspiciously cheap but if they last a couple of years they won't cost much to replace.

The rails come with just a cable tie in the end holes so not really. I shall put a protruding screw in each end to prevent the block sliding off when I build the printer.

Amazon delivery - Mini linear rail for 3D printer. Seems excellent.

If you don't polar align properly your images won't be clear - they will suffer from star trails unless your exposures are very short .

I certainly enjoyed building mine and in fact I'm still adding refinements. My comment was rather "tongue in cheek" as I didn't really care what the total cost has been - it's a hobby and as long as I have enough money to feed myself, keep myself warm and pay the bills, the expenditure doesn't matter. Life is to be enjoyed.

I never dared tot up all I spent on my observatory!!

I've just ordered a 300mm one of those linear rails to examine - arriving tomorrow. This will be long enough for one of the Y rails on my new Mini printer.

For greatest benefit I think all axes need upgrading particularly the X axis. I think the Z axis may be less critical. I'm wondering if a single slider on the X rail would be sufficient to hold the extruder and hotend plus fans etc. Is there any adjustment in the sliders to take up slack?

WOW!! That is a wonderfully flat bed. My Concorde bed seems to curl up on one corner by a few tenths of a mm! Are you using the new linear rails for all three axes now?

The way the RPi will drive the Arduino using the control buttons above means some small changes are required in the Arduino sketch. The three buttons and hence the three data states will be mutually exclusive - 1 of 3 on. In fact the number of control lines could be reduced but since the hardware is already built I shan't bother. Th upshot is that the sketch will need to detect the rising edge of the GPIO line and then ignore the high level once detected. The motor drive will be terminated by the appropriate limit switch, timeout or the STOP/ABORT signal from either push button or RPi. The Ekos button will retain it's state from operator action with the Light indicating the result of the roof operation.

None too good for the observatory floor though!!

Working on the RPi INDI driver code. The standard Astroberry Board driver simply turns relays on and off with two buttons for each. For this project I need something slightly different. The ROR motor electronic relay has three states OFF, OPENING, CLOSING. The ROR control could be implemented in a few ways :- One light and 3 buttons in a row. Buttons for CLOSE, OPEN, STOP/ABORT - Light :- Closed, Open, Moving, Fault Three rows of lights each with one button. My original idea. Three rows of lights each with two buttons. (3 of the 4 standard Astroberry Board relay controls) Two rows of lights each with two buttons. Option 1. would work but in the event of a fault there is no indication of whether the roof was opening or closing when the fault occurred. OTOH a fault would need human intervention in the observatory and the LEDs on the control panel would show which way the roof was moving. Also, if I had just operated the remote control I would know whether I was opening or closing the roof. If the Ekos Control panel works as I think with this setup, I think it would be quite adequate as well as nice and simple. (Less is more.)

Delivered by DPD from FLO

Yes indeed, adequate drainage is very important - I "speak" from experience!!

My ground slopes too and I dug it out rather than building up. It was a mistake as the hole fills with water in heavy rain and I need a sump pump to clear it out. I too didn't want the observatory too high but for my own benefit in the view from my living room rather than neighbours which are cattle. With neighbour's fields on three sides the height made little difference to the astronomy. Nigella, I guess it depends on what trees you can clear and hence the view from the pier.

Note to self - Astroberry Files are off Documents,