Mike's roll-away shed observatory

[toxic]

just screw a timber rail to the part of the walls where the roof joins use big washers on the outside and yer good to go

[RWB]

Hi looks a very nice job  but (and I apologise if I missed it) I did not see anything about  holdig it down

in the wind I know this is a major concern in the UK and assume it is over there

as I say if you already have it covered  I've already got my coat !!

Cheers and clear skies

Robin

[MikeODay]

just screw a timber rail to the part of the walls where the roof joins use big washers on the outside and yer good to go

Thanks for the suggestion ... I've decided to try and see how I go first with just tying down the base (the shed itself is bolted to the base). I'll keep an eye on it and if the walls move too much in high winds I will have to do what you suggested.

Cheers

Mike

[MikeODay]

Hi looks a very nice job  but (and I apologise if I missed it) I did not see anything about  holdig it down

in the wind I know this is a major concern in the UK and assume it is over there

as I say if you already have it covered  I've already got my coat !!

Cheers and clear skies

Robin

Yes I've been thiking about it and the guys here have been giving some very good suggestions.

I decided to and see if I can adequately hold it down by using turn-buckles attached to the shed base (the shed is bolted to the rolling base).

And if you will forgive looking under the shed's skirts ... this is the detail...

The next steps - in slower time - are to attach some trim to the edge where I cut out the shed floor (mainly for aesthetic reasons but also to reduce the risk of scratching the paint on the pillar as I move the shed about) , cover the lower sides of the shed (over the black builder's plastic) with boards and finally buy some more artificial turf to spread all the way around the visible sides of the deck (to make the underside of the deck more attractive (boss's instructions) and to also reduce the amount of dirt I am walking up onto the deck when the ground is wet.

[nightfisher]

Beautifully done, great craftsmanship and very well put together, a job well done

[toxic]

just the job 

[MikeODay]

Thanks guys.

[Swubba]

Your observatory has a twin here in the states.  Built it in early 2013.   Cheers!    

https://www.youtube.com/watch?v=2yYseL0Q1bo

[dtokez]

very cool idea

[saac]

Your observatory has a twin here in the states.  Built it in early 2013.   Cheers!    

https://www.youtube.com/watch?v=2yYseL0Q1bo

Cool build Swubba, really like your ability to broadcast - makes observing a bit more of a sociable experience - I hope to be able to do something similar.

Jim

[MikeODay]

Your observatory has a twin here in the states.  Built it in early 2013.   Cheers!    

https://www.youtube.com/watch?v=2yYseL0Q1bo

That is a very cool setup.  So far mine shed is really just a rolling cover but I gues I might be tempted to fit it out a bit as the nights start to cool in few months.  I love the video - I wish I had taken more photos.  The end result you achieved with your observatory and landscaping is very neat and seems from the video to fit right into your yard.  Of course I'd probably fall in the pool after I walk out of the shed like a zombie  at 3am

Thanks for sharing.

[MikeODay]

The 'masonry pollyfilla' I used to finish off the top of the pier finally dried so I sanded it back and painted it with the same paint as the pier - satin (semi-gloss) black enamel. It looks brighter but that's just the reflection of the sky.

It's not perfect (too many bumps and scraps I cound'nt get out with the sandpaper) but I'm happy enough with it.

So the pier is pretty much finished. Although, I'm giving some thought to putting a couple of small strips of clear contact plastic down low either side of the pier where the cut-out of the shed nearly touches the pier to help protect the pier from scraps and scratches. I might also cover the top of the pier with plasitic so i can use it as 'table' for bits and pieces without scratching the paint.

[Gina]

You should be well satisfied with that - I would be   Puts my plain bare concrete slightly crooked pier to shame   Not that I'm worried - does the job well and that's what matters.  A slightly smarter one would have been nice   I could cover it be can't be bothered   I would love one a nice as yours though

[MikeODay]

Thank Gina, I am quite happy with the way the pier turned out - in particular that by good management (read mostly beginners luck) that the pier ended up level .

As for the effort, well ... partly this results from a newbie's lack of confidence in what will work and for how long the result will stand up to wear and tear.  The whole job is terribly over engineered and I'm sure it should be possible to achieve very acceptable results by cutting the right corners - I just did not know which were the right ones.  As for the finish of the pier - well, at least I could control that to some extent; as opposed to my complete lack of skill in finishing off the decking so that the ends of the timber meet nicely

I've been following your threads and I'm very impressed with your design and manufacturing skills; designing and manufacturing your own parts must be very satisfying.

Cheers

Mike

[Gina]

Thank you Mike   Yes, very satisfying

[MikeODay]

We have had period of very hot and humid weather and the inside of the shed is at times like a sauna so i've decide to install fans to force the hot damp air out through the vents at either end of the shed. Most of the input air should come up from around the base of the pillar and the edges of the cut-out in the floor. I am hoping that it won't bring with it too much dust as the deck is raised above the ground at that end of the deck by around 40cm.

I've purchased a n 18W 12V (nominal) flexible solar panel and ordered two 12V 10W fans.

http://www.jaycar.com.au/productView.asp?ID=ZM9150

http://www.selby.com.au/sunon-cooling-exhaust-fan-12v-120mm-f1165.html

Does anyone have any experience with solar panels? The guy in the shop convinced me to buy a regulator to protect the fans from over voltage in bright sunshine but I'm not sure that 19.4V maximum @ 9W per 10W rated fan will actually bother the fans. Has anyone installed a panel without a regulator? The regulator he sold me is designed for charging a battery so if I am going to use it I'll have to run some tests. In particular, what is its maximum output voltage ( I assume that it will be 13-14 V) and will it still output anything when there is not much sun and the voltage drops to a few volts.

[MikeODay]

I finally managed to get the fans working.

Having glued the panel to the roof and installed and wired-up the fans I had real trouble getting the fans to work.  They would work sometimes but then at other times they would simply fail to start.  I thought the problem was due to the fans stalling so I installed a 4700 micro Farad capacitor across the circuit for the fans but this did not solve the problem.  I then double checked the regulator and for some reason it usually keeps the output turned off as the voltage rises and keeps it turned off even when I toggle the on/off switch I installed.  Only after multiple on/off cycles does the regulator then activate the output. 

The upshot of all this is that I have now removed the regulator and the fans seem to be starting and running as expected.  I will be risking exposing the fans to potentially higher than rated voltage but given the limited current that the panel is capable of I think the power dissipated in each fan should be well under their rated maximum power.  Anyway, at least they seem to be working ok now.

[MikeODay]

All good so far... both fans start by themselves even when the sun is low and there is quite heavy cloud. Although we have had mostly overcast days so far so I have not been able to see how the fans will react when there is full sun on the solar panel putting maximum power through the fans.

Here is the small and very light solar panel on the roof .

And here is one of the fans bolted into the vent at one end of the shed (the other is directly opposite). Both fans are blowing out as I have sufficient input air coming up from the beneath the shed via the cut-out around the pier. You can't see any cables because I removed the roof and ran the cables along the top of the walls so they are neatly out of the way. The switch isolates the panel from both fans.

I'm going to keep an eye on the air flow when the fans are running at maximum revolutions and see if I need to fill in the gaps between the sides of the fans and the edges of the vents. I'm leaving the gaps at the moment as they allow a little more air flow when the fans are not running - including at night.

[tekkydave]

Hi Mike,

I like your obsy. I'm thinking of doing something similar, probably using the same Keter 4x6 shed. How many castors did you use and have you had any issues with them being only 50mm diameter? I was thinking more of 100-150mm but I haven't worked out how many I would need yet.

[MikeODay]

Hey Dave

I used 16 castors in four rows - note that due to unevenness of the base and the deck not all are touching all the time.

The only issue is that the shed does not reliably track in a straight line and will tend to move to the left or right a couple of inches depending on the point at which I am pushing from.  It is not a serious problem though - I simply re-position the shed using a 'furniture lifter' I ordered on Ebay.  

I used a large number of castors as I wanted to ensure that I had adequate support for the floor so I could stand on it anywhere without putting to much strain on any part of the base (noting that a reasonably large section was cut from it).  I'm sure I did not need so many but not knowing any better I decided on a very conservative approach.  How many you need will depend on the strength/stiffness of your base.  If you base is perfectly strong/stiff then you will only need four castors at the extreme corners.  I don't know that the diameter of the wheels is necessarily the most important considerations (although it may impact tracking).  Their weight rating is though.  I would suggest that each castor should be rated at approx. 

rating = 2 x total of weight shed and base / number of castors

Cheers

Mike

[LukeSkywatcher]

So the pier and scope remain in the same place but the whole shed rolls back?.

I like that.

[MikeODay]

Yes that's right.  It rolls quite easily and I tie it down once it is back over the scope.

[tekkydave]

Thanks Mike. One idea I had was to put a lip or collar type arrangement on the pier that the floor would slide under. This would stop the shed from lifting due to wind etc. It would depend how well anchored the pier is in the ground - you wouldn't want it lifting up especially with all that expensive gear sitting on top

[Gina]

If you build your pier and base with a tonne of more of concrete like a lot of people, I don't think you will have any problem with it pulling out of the ground   Probably heavier than the shed base/foundations anyway.

Oh and if you would like a recommendation for heavy duty wheels and track, FH Brundle do wheels and track designed for heavy metal rolling gates.  I have just replaced my ROR track and wheels with the FH Brundle 300Kg rated kit as you might have seen and it's superb.  Very easy to move and would be quite suitable for a roll off shed.

[Physopto]

I finally managed to get the fans working.

Having glued the panel to the roof and installed and wired-up the fans I had real trouble getting the fans to work.  They would work sometimes but then at other times they would simply fail to start.  I thought the problem was due to the fans stalling so I installed a 4700 micro Farad capacitor across the circuit for the fans but this did not solve the problem.  I then double checked the regulator and for some reason it usually keeps the output turned off as the voltage rises and keeps it turned off even when I toggle the on/off switch I installed.  Only after multiple on/off cycles does the regulator then activate the output. 

The upshot of all this is that I have now removed the regulator and the fans seem to be starting and running as expected.  I will be risking exposing the fans to potentially higher than rated voltage but given the limited current that the panel is capable of I think the power dissipated in each fan should be well under their rated maximum power.  Anyway, at least they seem to be working ok now.

I suspect that the regulator is of the type that has a reverse voltage protection. This is to protect a battery from putting power back into the PV cells when there is not enough light, i.e. at night or when very overcast. That could damage the solar cells.

If there is not a battery in the circuit the reverse voltage protection is not necessary. There is unlikely to be enough wind to power the fans in the reverse direction to cause a problem. If there is a possibility of that just fit a diode of sufficient capacity. This will of course reduce the out put voltage from the PV cells by 0.5 volts( forward volt drop).

Regards,

Derek