Yet another Power supply project.

[idbvideo]

Plan Z Z alpha or whatever.

I have a 40Ah Ring booster pack that actually works extremely well, it has an invertor and supplies 12V without a problem. But I really hate cigarette lighter connectors. So I have this idea to put a box on the thing to provide power to the mount, camera and maybe include some sort of dew shield driver, whatever you want to call it.

I was going to try to generate the necessary power for the camera using a voltage regulator to do the honours but another forum on 3d printers suggested one of these:

http://www.ebay.co.uk/itm/251136503012?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

At that price I have ordered 5 :-) One for the camera supply, one for 5V to power a USB hub and 3 spare.

I only need one for this project but I am sure I can find uses :-) Actually I am also thinking of real portability without the need for the big power pack in future for true grab and go :-) RC lipo batteries, a 4S battery pack connected to one of these will easily power an observation session for an evening.

Anyways one of the other thoughts was to monitor the voltage. Yeah I could do the whole lot with an Arduino using voltage dividers into the analogue inputs, and drive an LCD but hey for the price, I thought a couple of these would be good :-)

http://www.ebay.co.uk/itm/351026520215

I bought a few ;-)

One will monitor the voltage to the mount, one to monitor the voltage to the camera. and maybe one to monitor 5V

The plan is to print a box so the whole thing must fit into a 5.5 x 4 x 4 box.

I was thinking about  putting a 4 port USB hub and a serial to USB adaptor in there too. I may be asking too much though ;-)

Any dew heater will be 3 -4 channels. I may be struggling for space here. Any thoughts on a really compact dew heater supply?  I could cut it down to 2 channels, I don't really need 4, but expansion?

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I have been working on the enclosure and main wiring design  for my power supply box.

The usual circuit layout mainly power supplies.

I did a quick model of the DC - DC convertor and the LED voltmeters based on dimensions given on the sellers sites. A bit of guesswork on the hole positions etc.,

The enclosure is based on the maximum I can print out on my Duplicator so that's why the constraints.

In this picture you can see that the DC - DC convertor is actually quite small so there should be no problems with those.

I am using 3 voltmeters, one for 12V, one for 7.5V and one for 5V. The main reason is because they are cheep and only take up the space of a 3x8segment LED display.

I wont need to have a separate indicator to tell me the unit is on.

One thing I like about using 3D modelling, is that if you create models of the main components, you can position holes and stand offs pretty accurately. I may have to re-model the DC-DC convertor and volt meters when the real bits arrive, to get the hole positions right, but the overall fit will be fine.

The enclosure itself will effectively fit on the back of the Ring power pack.

[idbvideo]

Well the LED voltmeters arrived, they should fit OK in my enclosure. There is one minor issue, that I may have to account for - The LEDs are pretty bright, so I may have to put a filter in front of them to reduce the brightness.

You can't tell how bright from this photo unfortunately.

At least they are red

I am now onto researching dew heater controller designs.  

The plan currently is just to have the one dew heater on the OTA, Not sure if I need one on the star sense accessory, but If I did, a dual channel controller would be OK. The only real question is do I go for 4 channels for an upgrade path? I don't intend to buy another telescope.  

[Dave_D]

i build my camera power supply into my dew heater box, a 150mm x 80mm x 50mm project box off ebay. works a treat

the dew heater board is one of these and seems to work fine (i paid a lot less than this one though):

http://www.ebay.co.uk/itm/NJ981-12V-3-CHANNEL-RGB-COLOUR-LED-TAPE-DIMMER-CONTROLLER-FOR-NJ961-/271410393300?pt=UK_Light_Fittings&hash=item3f3151f0d4

there's still room for a 4 or 5 port usb hub in the box too.

when i have time, i'll be replacing all my connectors with something like these

http://www.ebay.co.uk/itm/2-pin-round-metal-power-connector-locking-plug-GX16-2-for-Yaesu-FT-480R-etc-/191191817375?pt=LH_DefaultDomain_3&hash=item2c83eb9c9f

[idbvideo]

I was thinking about those power connectors, but couldn't find any!! Thanks :-)

[mhard26339]

Hi, I used the same RGB Dimmer as Dave, a project box from Maplin, must admit I used phono plugs as output but it works a treat. My power source for the mobile set-up is cigar plugs, hard wired for the dome. No problems with either, mobile set-up costs approx £15.

easy to do if you are mechanically savvy but not so hot electronically, its all done for you just a little bit of organisation required. Link to the UK seller is although cheaper if you wait from China. http://www.ebay.co.uk/itm/NJ981-12V-3-CHANNEL-RGB-COLOUR-LED-TAPE-DIMMER-CONTROLLER-FOR-NJ961-/271410393300?pt=UK_Light_Fittings&hash=item3f3151f0d4

Regards

Mike

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I am trying to build up my enthusiasm to go get the parts to make a heater controller, I really only need the 555 timer and MOSFET as I have most of the other bits anyway. Its just a 40 mile round trip to CPC.

Laziness made me send for the stuff.....

[idbvideo]

One of the reasons for making my own controller is that I can make the circuit board in whatever shape I want to, to make it fit into available space.

Once all the bits are in my sticky mitts I will strip down a USB hub, I refuse to make one of them, and decide on available space. The heater controller will probably be a regular shape but you never know.

[idbvideo]

Wow its been a few weeks since I did anything on this project. The only thing really stopping me from progressing is that I have the dew heater controller to produce. My first (almost ever) circuit production revealed this

In realty there are a number of issues with it, but they can be overcome to be honest. I over etched the circuit and one of the tracks resulted in a pad missing. It was present on the developed photo resist board after exposure, Its a resistor and I can create a track using wire if necessary. Once drilled and populated I can finish the 3D design of the case.

I have been thinking about the case/box too, I am tempted to create backlit captions/legends on the case for each of the connectors. Basically this involves printing some lettering that passes through the box lid, which will be lit by a red LED inside the box. The technique is similar to the way aircraft instrument panels are lit, but without Electro luminescent panels. The lettering needs to be in clear plastic. I have tried the technique on some switch caps with legends and it will work. The switch caps are intended to mimic those used in the cockpit of an airliner, if I ever create a home cockpit :-)

To be honest its all about what is possible, not what is the best way forward. In other words If I can do it this way, and it looks cool then why not :-)

The box will be printed in grey PLA with clear PLA for lettering.

Once I have drilled the dew heater PCB and built it, I can progress :-)

[idbvideo]

I seem to have lost the way on this hehe.

One of the things that have waylaid me has been that the power tank that I have been using seems to not want to charge. Actually it takes forever, mainly because I have lost the original charger, but the one I am using does eventually charge it, and it hadn't been charged in ages. Not good for gel batteries.

I have, in the mean time made what I call a grab n go power supply.

The electronics are now assembled and all the plastic parts printed out and in the assembly stage. (pics to come)

I have used 2 DC-DC buck convertors - one for 12V (scope power) and one for 8.4V (camera power)

The battery is a 22VDC 6 Cell Lipo that I normally use for a RC helicopter!! Its 3 Ah so should last an evening at least. Even if it doesn't it was fun designing and building the thing. There is a Volt meter in it to act as a powered on indicator - honest :-)

The DC DC convertors were £1 each, and the volt meter was about £2.50

Slowly getting there.....