# Dimmer uv tube ballast



## Pendragon (Dec 8, 2008)

Hi peeps, I had a link to a website that sold a uv tube starter that had a built in timer and dimmer.

You could set the timer to slowly bring the tubes up to full strength over a 30 minute period, and then dim the tubes back down again at the end of the day.

has anyone seen or heard of one of these starters?

Cheers

Jay


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## Jim2109 (Mar 30, 2009)

ive got one, its an Exo Terra Light Cycle Unit.

dont bother, its crap. you cant buy them in the UK, i got mine imported from Germany. its got a timer that can be set to 10, 12 or 14 hours (i want 13, and its annoying that it only goes up in 2 hour increments since most rainforest environments have 12-13 hours of sunlight depending on the time of year).

it then also dims up and down over an 18 minute period. but it doesnt actually dim. it does nothing for the first probably 5 mins. then it comes in to about half light in one hit. then 2 more steps over the remaining time take it to full. and it does the same to switch off - drops to half straight away, then 2 smaller steps. its really not worth having. flourescent bulbs simply cant be dimmed properly in the same way as filament bulbs. its not really worth the bother and expense TBH.

the better way to do it (which is much more realistic anyway since UV starts low and gets higher as the sun rises in the sky) is to have spot bulbs on a timed dimming device and have the UV tubes come on an hour later. 

i have built such a device using a couple of project electronics boards!! i cheated, i bought them pre-built lol. but basically i have a timer control that sends a signal to the dimmer board. this signal then commences the dimming and the bulb goes from zero light to full light at a completely even rate. no steps!! the dawn/dusk period is changeable from 1 second up to 2 hours and does the same for both. then my timer board stays live for however long i want (accurate to the second and changeable to any number upto several days iirc) and when it switches off the dusk dimming starts.

the only problem with the current setup is that the timer has to be on and off for equal periods of time. so if im having a 12 hour day then there is also a 12 hour night. but if i want 11 or 13 hours.....you can see the problem. so i use a timer socket to switch on the timer board, which then immediately commences its timing. then i have the socket switch off a couple of hours after the dusk has finished. so this way its completely configurable!!

i plan to possibly buy another project board that times using a clock, so it can switch on and off at any time you want, accurate to the minute.

if youre interested in how ive done it let me know and il go into details with links to the boards, etc. personally i think its the most natural, realistic and best way to have things setup. its more effective when using MVB/MH bulbs because they cant be on all day long. but it would still be good just with UV tubes


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## Alex (Jun 14, 2009)

Im very interested in the board pinouts, Could you go into more detail please?

just the thing im looking to make!

Thanks


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## cordylidae (Nov 2, 2008)

Xenon said:


> Im very interested in the board pinouts, Could you go into more detail please?
> 
> just the thing im looking to make!
> 
> Thanks


i would be to


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## Pendragon (Dec 8, 2008)

Hey Jim,

Thanks for the info, I'll p.m you, I think you might have a couple of others interested : victory:


Jay


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## jaf2212 (May 10, 2008)

These do sound good, esp if it simulates the lighting better


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## Jim2109 (Mar 30, 2009)

basically youve got 2 circuit boards, both purchased seperately.

circuit 1...

this is the timer circuit. there are better ways to do this than what i have done. the circuit is just a multi functional timer that operates an SPDT relay (NO, NC and C connections. for those who dont know about relays read on for an explanation). it can be used in 7 modes iirc, personally i use the toggle mode (equal time on and off)

this is the timer....
Multi-Mode Universal Delay Timer Relay Board (3141)

this is the user manual for it...
http://www.quasarelectronics.com/kit-files/electronic-kit/3141.pdf

its £17.95 as a kit, or £22.95 pre-assembled. i bought it assembled, so much easier!!

you need to feed it 12v power (easily done using a regulated 12v power supply). then for outputs it just has the relay outputs. an SPDT (single pole, double throw) relay is basically like a toggle switch. it has a common connection (C) which you feed say 12V to. then it has NO (normally open), and NC (normally closed). there are 2 other pins which feed the coil. on this circuit board these are wired to the timer. when the coil receives a current it creates a magnetic field, which attracts a sprung lever inside the relay which then contacts the NC terminal, feeding this whatever voltage there is at the C terminal. when there isnt a current in the coil then the lever springs back to NO, and feeds this the voltage from C. hopefully that makes sense to everyone.

the second circuit, circuit 2...

is a night/day light dimming module. this operates from 230V, but all of the control circuit is stepped down to 12V, which is handy! so you connect your 230V mains wires to it (live and neutral), it then has an output that you connect to your lights. there is only one terminal block, but you can connect as many lights as you want, upto 750W total power draw.

the control circuit, which is 12V as mentioned, has 3 connections. one is a common terminal, then there is the day trigger and the night trigger. here is where the 2 circuits link together.... you feed the common terminal to the C terminal on the relay of circuit 1. you feed the Day trigger to the NC terminal of circuit 1, and the Night trigger to the NO terminal of circuit 1.

so lets talk the process through from start to finish....

the timer circuit is plugged into a socket timer (just any standard timer socket that youd use for other reptile purposes will do). the timer circuit isnt on and thus hasnt triggered yet. there is no voltage through its coil, and all circuits are at rest.

the socket timer switches on at 6:00am. this gives 12V to the timer circuit (circuit 1) which goes live and straight away starts its toggling cycle. this sends the relay coil live, and NC is switched on. this sends 12V to circuit 2, the lighting controller which then commences its day cycle.

lets say the dimmer is set to 1 hour. so it receives 12V at the day trigger and then starts to dim the light in, after 1 hour it is fully lit. the timer circuit remains the same for however long it is set for. lets say 12 hours. after 12 hours (including the hour it took to bring the light in) at 18:00 it switches off, sending the relay contact to NO. this releases the day trigger and then triggers the Night trigger. this then sets the bulb about dimming down from full light to no light over 1 hour.

after that hour there is no light, and the time is 19:00. due to the toggling mode the timer circuit will switch back on again at 6:00am the next day and repeat this cycle. however we are using a socket timer here so that there is flexibility. the socket timer switches off at 19:30 killing power to all circuits. when it switches back on at 6:00am the next day the timer is reset, and the cycle starts again. so if you wanted to run a 9 hour day or a 15 hour day, you could. there are other timer modes within this circuit setup that could acheive the same thing. this one was just the easiest to get my head around and it works, so why change it lol.

here is a link to circuit 2, the lighting controller...
Dusk/Dawn Effect Lighting Controller Module (230Vac, 750W) (CR0011)

and the user manual...
http://img.icnea.net/Forum/E6001/ftp/R-11_English-Esp.pdf

this one comes pre-assembled only.

a better way to do this circuit, but at MUCH more expense is to use this circuit as the timer instead...

24 Hour Clock/Time Relay Switch, 2 Outputs (1180)

its just a 24 hour clock circuit. so instead of having the simple timer circuit and a socket timer plug, this circuit does it all in 1. its uses are far wider ranging than we require though, and it costs £50!! i already have timer sockets so it made no sense to spend £50 instead of £23 on the simpler circuit. however you could probably get this circuit for the same price as the timer circuit and the socket timer if you dont have one spare already.

wiring it all up is simple enough, took me about 10 mins. i bought some plastic enclosures from Maplins to put the circuit boards in. 230V mains isnt something you want to touch by accident lol. it hurts, a lot! ive got mine all wired up and running and it works perfectly.

as for the specific application of use, it depends on the lights youre using. my personal suggestion would be as follows....

if using just tubes for UV....

have your basking bulbs on this dimmer/timer setup. length of day depends on what type of lizards you have. for chinese water dragons the day varies from 12 hours upto 13.5 hours from first light to last light. dawn and dusk last approximately 40 mins each (included in that time). so lets say its the longest day of the year, 13.5 hours.

you have the basking lamps come on with the dimmer at 05:00. it takes 40 mins to reach full light at 05:40. then at 06:30 you switch on the UV tube using another timer. this is on until 17:30. then at 18:20 you dim the basking lights down for 40 mins and at 19:00 you have darkness.

this gives you a clear dusk and dawn period (which is important for reptiles. they dont want to be woken up suddenly with midday sunlight! and for diurnal species, they use the dusk period to find a resting place for the night, and thus sudden darkness messes them up. plus its totally unnattural), it also gives you a clearer middle of the day period with high UV.


now for the better setup - MVB + UV/daylight tubes + basking lamps...

treat it the same for basking lamps, on at 05:00, full light at 05:40. then at say 07:00 the MVB bulb comes on, ideally with a daylight tube as well. then at 10:00 the UV tube comes on to represent the time of day when the sun is at its strongest.

at 14:00 the UV tube goes off. at 17:00 the MVB bulb goes off (giving 10 hours of high intensity UVB), then at 18:20 the basking lamps dim down to darkness at 19:00.

those times are open to tweaking, its just some made up times for example purposes. those sunrise/sunset times are genuine Vietnamese rainforest times though for July!

i had a long discussion with Darren from Megaray/Kimbos Reptiles regarding this setup, and the above is based on his recommendations as well as my own research, plus some common sense and natural observation thrown in for good measure.


P.S. for anyone who knows what they are doing with electronics, a cheap and easy way to make a 24 hour timer circuit to replace circuit 1 would be to use a socket timer and wire that into a mains SDPT relay. youd probably need some circuit protection as well to prevent spikes, etc. but this would give you a 24 hour timed relay which is essentially all circuit 1 is doing. it would be cheaper this way 

also, i havent mentioned it, but its in all the user manuals i linked to - the settings are all done with DIP switches and potentiometers. the manuals make things very self explanatory. if you dont know Binary yet then learn it, the timer circuit has the timing set in seconds using a DIP switch for binary


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## Alex (Jun 14, 2009)

Thanks mate! really apreciate that!


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## Pendragon (Dec 8, 2008)

Cheers Jim, very comprehensive.

: victory:

Jay


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## haunted-havoc (Aug 6, 2009)

they looks to me like velleman boards. oh how i despise soldering these. you were so much better off using pre-assembled ones


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