Tekkydave low-cost obsy build

[tekkydave]

In true sgl style this thread is to document the progress of my obsy build. Well its not really a proper obsy more a game of two halves. We have quite a small back garden - only about 7 by 7 metres so no room for a proper roll-off roof obsy anyway. So I decided to keep costs as low as possible and make the best of what I have. I have recently set up a new metal shed so I will be using that as my sitting/work area/warm room. I also plan to re-use an area which is currently a pond as an area to place a home-made pier. The pond is currently at the end of a stream which is fed by a waterfall at the top end. The pond will be relocated next to the waterfall as the stream is proving a bit of a maintenance nightmare and causes too much evaporation of the water.8

This shot shows the current situation.

This shows the pond from the other direction showing the shed in the background

The pond is quite deep as it acts as a reservoir for the waterfall and stream. The pier will be set in concrete and the area around it paved.

The pier itself will be made from wood to keep costs down. I'll probably use four 4 inch fence posts glued & bolted together giving an 8"X 8" solid pier.

I made a start today by panelling one side of the shed just inside the doorway and installing a power feed from an adjacent external power socket.

The internal wall prior to panelling

And after installing 2 panels. These are actually panels from an old wardrobe. Never throw anything away

Next I ran a cable from the external power socket using external grade rubber cable and 20mm cable glands.

I installed 3 cable glands to give me some more for future feeds out to the pier. I put a short length of offcut cable in each to keep it watertight.

Finally a 6-way switched adapter fixed at the top of the panels. This will be used to power the resident PC, power supply for the scope, monitor etc.

Next steps will be:

Build & install the pier. A top plate will be made from steel plate to mount the scope.

Set up a fold-down desk attached to the shed wall panels.

Install PC in a protective wooden sleeve.

Attach monitor to wall panel.

Install cables from shed to pier.

[tekkydave]

Started clearing the site for the pier today. Removed all the pebbles from the pond & filled 8 rubble sacks! Left a landing area in the pond for any wildlife that falls in to get out.

I have all the parts for the pier:

four 4"x4"x6' posts

10 bags of postfix

coach bolts, nuts, washers & waterproof wood glue to tie posts together.

two 200mm x 200mm x 10mm steel plates to make mount plates

four M12 x 300mm length studding, washers & nyloc nuts to separate mounting plates

four M12 coach bolts to bolt lower plate to top of pier

I have also been testing that my obsy pc "Saturn" can connect to my focuser, camera and scope. The focuser works ok and I can connect to and control the scope from CdC and also using the Celestron NexRemote utility. This is an old version and has not been updated for the latest StarSense hand controller but its ok for moving the scope around manually. I tried all the USB devices using 10 metre repeater cables including the ZWO ASI120MC. It wasn't happy plugged into a hub with lots of breakup. I think it needs its own repeater cable so I will use two - one for the camera and one for everything else.

[Owmuchonomy]

Good luck Dave. Are you happy a wooden pier will be rigid enough? I've just drawn up my plans in rough and asked a mate to help me with the base. I don't think I'll get around to it until the Autumn though.

[Mukv]

Greetings

it's amazing what can be achieved in small spaces, my garden is 7.5m X 6m and also had a small pond to remove but the finished shed / obsy is extremely satisfying when it gets dark.    

http://stargazerslounge.com/topic/205719-roof-roller-system/

Good luck with the adventure.

Andy

[tekkydave]

Good luck Dave. Are you happy a wooden pier will be rigid enough? I've just drawn up my plans in rough and asked a mate to help me with the base. I don't think I'll get around to it until the Autumn though.

It will be 8" by 8" so should be.

[tekkydave]

Made a start on the power box which will be mounted inside a waterproof box on the pier. It will provide various DC voltages: 12v for scope, 7.5v for canon dslr, 5v for USB hub. These will be generated from the 12v feed via DC-DC buck converters. There will also be two 12v PWM 12v feeds for dew control via LED dimmers. Ill be having a go at making some diy dew bands at some stage. I also have a 7-port USB hub to integrate into the box.

The xlrs mounted into the front panel. Five 5-pin for the various volts feeds (five leftmost), two 3-pin (two rightmost) for the dew control feeds

The power box inside the waterproof box

[tekkydave]

The buck converters are these http://www.amazon.co.uk/gp/product/B00EYT1DWW/ref=wms_ohs_product?ie=UTF8&psc=1

The LED dimmers are these http://www.ebay.co.uk/itm/4X-DC-12V-8A-Light-Dimmer-Brightness-Adjust-Control-For-Single-Color-LED-Strip-/360867901392?ssPageName=ADME:L:OC:GB:3160

[Mukv]

^Greetings

^{Look at these before you buy from ebay}

^{http://www.ebay.co.uk/itm/DC-12V-8A-LED-Light-Dimmer-Brightness-Adjustable-Bright-Controller-Single-Color-/191253745787?pt=UK_DIY_Material_Electrical_Fittings_MJ&hash=item2c879c907b}

^{I use these with no problems.}

^Andy

[tekkydave]

^Greetings

^{Look at these before you buy from ebay}

^{http://www.ebay.co.uk/itm/DC-12V-8A-LED-Light-Dimmer-Brightness-Adjustable-Bright-Controller-Single-Color-/191253745787?pt=UK_DIY_Material_Electrical_Fittings_MJ&hash=item2c879c907b}

^{I use these with no problems.}

8

^Andy

Thanks Andy. I think those are the same as the ones I have bought. Good price though. I paid £9.89 for 4 units not £58.95 as stated on the ebay link in my post.

[tekkydave]

Some more progress today. I have built the fold-down desk inside the shed. This is also made from a panel from the old wardrobe with hinges so it can be lifted up out of the way when not in use. The desk will protect the wall-mounted monitor - after all this is a working shed

The desk in its down position

And in its up position

The single leg is very sturdy and hinges out of the way when the table is lifted. The table will be vertical and leaves a 130mm gap which is room for a 19" monitor on a vesa wall mounting bracket. I need to find a catch of some kind to keep the table up. I will probably fit the PC below the table in some kind of protective wood sleeve.

[L8-Nite]

Did you put an " RCD " safety adapter somewhere in line on your electrical feed ?

[tekkydave]

Did you put an " RCD " safety adapter somewhere in line on your electrical feed ?

Good point - Yes I did. The mains feed comes from a dedicated external supply box in the garage. It has a 16A RCD for power and 6A regular breaker for lighting. I did consider putting an RCD in the shed but its not recommended to put 2 on the same circuit as they can interfere with each other. The power supply to the mount will be 12v anyway so it wouldn't have added anything.

[tekkydave]

Ordered a "counter flap latch" to keep table up when stored away http://www.ebay.co.uk/itm/151359286846

[L8-Nite]

Good point - Yes I did. The mains feed comes from a dedicated external supply box in the garage. It has a 16A RCD for power and 6A regular breaker for lighting. I did consider putting an RCD in the shed but its not recommended to put 2 on the same circuit as they can interfere with each other. The power supply to the mount will be 12v anyway so it wouldn't have added anything.

Here with the damp UK weather, a ground fault safety device is cheap life insurance for sure.     

[tekkydave]

Here with the damp UK weather, a ground fault safety device is cheap life insurance for sure.  

Yup

[wuthton]

If I could make a small suggestion....

The green stool certainly fits with low cost but I'd be tempted with investing a couple of quid more on the seating arrangements.

[tekkydave]

If I could make a small suggestion....

The green stool certainly fits with low cost but I'd be tempted with investing a couple of quid more on the seating arrangements.

Ha ha. I was using this to sit on whilst building the desk. I could do with something that swivels so I don't need to push in & out.

[tekkydave]

Raining cats & dogs here today so did some more work on the power box for the pier. I bought some 14 swg tinned wire to connect the xlrs in a bus style but it turned out to be too thick (2mm) to go into the 5-pin xlr hollow pins. I looked around for an alternative and found an offcut of 6mm twin & earth. This is usually used for cooker/shower circuits so is quite hefty. The earth core is about 16 or 17 swg and the L/N conductors are 7 x 19 swg. After stripping & unravelling the cable conductors I paralleled up the pins of the 5-pin xlrs and also the 2 pins of the 3-pin xlrs that will also carry 12v. I used the thicker wire for the ground and 12v lines and the thinner for the other voltages.

Not my neatest soldering ever but should be ok.

I'm also building a 12V 30A psu to live in the obsy (ahem shed) to supply the pier. It will also contain a small digital voltage/current indicator - more photos of that when all the parts have arrived.

[tekkydave]

Nice weather today so decided to put the wooden pier in the ground. This is made from four 100mm x 100mm x 1.8m (4" x 4" x 6ft) posts bolted together with coach bolts and set in the ground with postfix. It is located where the pond used to be so the hole is half dug already. I dug the extra 18" down to put about half the post below ground level. The soil at that depth is almost pure clay - I might have a go at some pottery later. Once I had bolted all the posts together which took a couple of hours I put the pier in the hole, levelled it up and put the first couple of bags of postfix in the hole and watered it. I waited 5 mins between putting each bag in and some water to allow it to soak in. Eventually after 9 bags I was at ground level. I added the last bag as haunching to keep any water away from the posts while it all sets.

The next step will be to fill in the dip where the pond was to ground level and put some slabs down to walk on. I also need to make a top plate and mounting plate for the mount. I have two 200mm x 200mm x 10mm black steel plates and some 12mm studding, nuts & washers. I will be putting my 127 slt on initially but plan to move up to an AVX before winter.

[tekkydave]

Here is a panoramic shot I took with my phone yesterday from the top of the pier. I managed to get it done just before I collapsed in a heap after planting the pier (very stiff this morning and lots of ibuprofen is being consumed - but not too much ). The directions are approximate but fairly close and the blocking out of the properties very rough to say the least. I plan to do a proper pano for stellarium using a decent camera so I'll try and post the details when I do it.

[tekkydave]

Did a bit more work on the obsy/shed today. PC and monitor now installed. After putting up the shelf I realised I had put the power strip in the wrong place so it was relocated below the shelf. I can connect to house wifi using an external 7db antenna but no connection from inside shed. I will be running a network cable in from the house at some stage.

[tekkydave]

Managed to drill the pier plates today with my new bench drill. The story of my search for the right drill is in this topic on SGL http://stargazerslounge.com/topic/224213-bench-drill-needed/

[tekkydave]

Today I have done a bit more work on the pier plates. The bottom plate has had a solid neoprene sheet stuck to it to act as a washer between it and the wooden pier. I have cut the 250mm M12 studding in half to make four 125mm lengths for the corners. I also drilled three holes at 120 degree angles to the centre in the top plate to accommodate the location studs on the bottom of the mount.

8

A quick dry-fit of the mount and it all goes together fine

Next job is to bolt the bottom plate to the pier using four coach bolts.

[tekkydave]

This is the base of the mount for those not familiar with it.

Base view. The centre threaded hole is a standard 1/4" tripod thread.

Side view showing location studs at bottom.

[Dazz8se]

Thanks for Sharing this build just starting my build done the ground work so far but I'm going the same way outside pier and logcabin as control room so will be following this thread with intrest

Dazz