DIY Viv Controller

[TheDon125]

Hi all,

I'm looking to design and build my own viv controller, and I'm curious, what sort of specs should I give the thing, what would be entirely silly?
(Oh, and I'm a EE by day, so I know my way around 120VAC, not going to zap myself here :wink: )
I also love the "open source hardware" movement, so once complete, I'd likely make the plans available for anyone who wants to DIY it themselves, or make pre-made versions for anyone who is scared to go the full DIY route.

Right now, I've got:

• Able to handle:
  • 1 150W basking bulb
  • 1 cool side bulb /ceramic heating element for temperature maintenance
  • 1 Fluorescent tube (I have a 39W Arcadia T5, but I'd guess up to 150W support here too)
• Ability to dim any non-fluorescent bulb
• Independent control of all bulbs
• Sunrise/sunset for non-fluorescent bulbs
• Delayed start/stop for the fluorescent (since this one cannot easily dim, have it start once the basking bulb brightens by some amount, and cut off before the basking bulb becomes too dark).
• Temperature monitoring (adjust basking bulb for proper basking spot heating, activate ceramic heating element if cool side becomes too cold at night)
• Humidity monitoring ???
• Control:
  • Sunrise/sunset to match local sunrise/sunset
  • Manual control (LCD screen, cable to PC, bluetooth to phone, web server to connect to your viv from any computer anywhere???)
  • Alerts (audible, e-mail, SMS!?) (temp too low/bulb burned out/humidity too high)
• DC supply for LEDs (extra light without the heat), also on the sunrise/sunset circuit
• ???

 

[TheDon125]

One concern I can think of is a "minimum on time". For example, if you go north or south enough, the day will become increasingly short during the winter months, eventually to the point where the UVB lamp won't be on long enough to keep the beardie healthy. Does anyone know what that "minimum on time" might be, approximately?

 

[hotpocketdeath]

[*]Delayed start/stop for the fluorescent (since this one cannot easily dim, have it start once the basking bulb brightens by some amount, and cut off before the basking bulb becomes too dark).

I'm all for DIY stuff as well. Personally, I was planing on purchasing an Ecozone vivarium controller myself, but if there is a cheaper alternative, I'm all for it.

One of my requirements is the ability to dim the Flourecent bulbs. I have a dimmable T5HO ballast in the mail right now on it's way. Specs on Ballast. These are powerline dimmable.

I was actually thinking that a Raspberry Pie would be great to set up as a vivarium controller. I know someone that has the know-how on how to build something like this and be able to write a software interface for it as well.

But keep us posted on your progress.

 

[TheDon125]

A RasPi would actually work fairly well as the brains, but it depends on what level of control you want. To operate as a web server, I'd take programming for a RasPi over an Arduino any day. For dimming lights, the RasPi operates too slowly to do anything meaningful (once you factor in all the other stuff the RasPi is running at the same time). I'm sure it's do-able, but now we're talking about installing an RTOS and other relatively uncharted territory.

Personally, I'd use a RasPi + Arduino combo, where the RasPi does the heavy lifting and acts as the go-between for the user and the Arduino, while the Arduino actually does the lamp control/sensor reading.

As for dimming the flourescent, I'd probably make a 4th port available that is dim-able like the basking and heating elements, but discourage people from using it unless they are absolutely sure their flourescent is dim-able, since the vast majority are not, and in fact can be damaged if you attempt to dim them!

 

[hotpocketdeath]

Have you checked out an Alamode?
http://hackaday.com/2012/07/23/the-proper-way-to-put-an-arduino-in-a-raspberry-pi/

My friend has one he is using to create an AC signalling tool paired with a RasPi.

 

[TheDon125]

Indeed, the alaMode would work quite well. Sadly, they're out of stock, so my plan is actually to start with a Teensy 2.0 and go from there.

 

[SeanFred]

I use 2 75W basking bulbs in my 6' Viv that I dim down to 80% for better heat distribution with a CHE on a thermostat keeping the low temp at night at 74F. When I was using a single 150W I was getting too much of a hot spot. I would love for them to come on full power in the morning and automatically dim down when the viv reaches its ambient temp of 92 on the warm side (basking site is about 105F). In the summer I have to dim them to 65% because the house is warmer.

I maintain a relative humidity of 30%

My lighting is on a timer that comes on at 0700 and goes off at 2200.

 

[TheDon125]

Ah, so a feature that, rather than having a pre-set:
"lamp will start at 0%, brighten to 80% to simulate sunrise, then stay there until sunset",

it would be useful to have a:
"lamp will start at 0%, brighten to 100% to simulate sunrise, hold at 100% until internal temperature reaches 92 degrees, then reduce brightness to maintain 92 degrees until sunset."

That's actually a fairly interesting idea, and what is most interesting about it, to me, is you could even do it in such a way that you would not need to specify exactly what the bulb reduces to, it could be fully automatic, which would eliminate all trial-and-error, or having to adjust for the seasons.

*keep in mind this would not work well with halogens. Those either need to run at full power, or have a somewhat more complex control scheme, to prevent from blackening and burning out quickly.

 

[hotpocketdeath]

*keep in mind this would not work well with halogens. Those either need to run at full power, or have a somewhat more complex control scheme, to prevent from blackening and burning out quickly.

That's not necessarily true. Most Halogens work the same as incandescent and you can actually improve the life span of a halogen by running it at a level below full operating power. Most of the time, the only real difference is the type of gas inside the bulb.

However, there are some halogens that have transformers or some other additional components that don't react well with dimmers.

 

[TheDon125]

Depends how low you dim the bulb. Halogen bulbs work similar to, but not exactly like a standard bulb. Halogen filaments run much hotter than standard filaments, which causes the filament to evaporate faster, and the filament then deposits itself on the glass of the bulb. The halogen gas that gives halogen bulbs their name scrape the filament off the glass and put it back where it should be (mostly). In order to do that, however, the bulb needs to get to a certain temperature. Run the bulb too cold, and you won't get to the right temperature, and the halogen bulb breaks down.

http://en.wikipedia.org/wiki/Halogen_lamp#Halogen_cycle

 

[hotpocketdeath]

Yes, that is the normal cycle, but read further into the link.

At much lower voltages, the bulb temperature may be too low to support the halogen cycle, but by this time the evaporation rate is too low for the bulb to blacken significantly. There are many situations where halogen lamps are dimmed successfully. However, lamp life may not be extended as much as predicted. The life span on dimming depends on lamp construction, the halogen additive used and whether dimming is normally expected for this type.

I still stand by my statement that most halogens can be dimmable. Of course I will agree that you can reach a point where the voltage is too low and lead to problems, but I'm sure limits can be place to prevent that.

 

[SeanFred]

I'm a techie, so you have my interest

 

[jamma2342]

I really wanted to do something like this about a year ago but I had no idea where to start. Since most people on here use the reptisuns with a basking lamp, I was thinking you could use the dimmer on just the basking lamp so it would simulate the sunrise and sunset and have the reptisun turn on when the basking lamp is at full power in the morning and turn off right before the basking goes to dim.

But keep us posted on how it goes! I'd love to see how everything works out.

 

[TheDon125]

I really wanted to do something like this about a year ago but I had no idea where to start. Since most people on here use the reptisuns with a basking lamp, I was thinking you could use the dimmer on just the basking lamp so it would simulate the sunrise and sunset and have the reptisun turn on when the basking lamp is at full power in the morning and turn off right before the basking goes to dim.

But keep us posted on how it goes! I'd love to see how everything works out.

That's largely what I am thinking as well. I'm still at a loss for the "minimum" amount of time the reptisun needs to be on though, to ensure that "safety" feature makes its way in to the code.

I'm also still speccing parts for this, so I wouldn't expect any updates until maybe a week or two from now. For now, it's just brainstorming. With parts I have on-hand, I can do simple on-off control of the lamps, and read temperature sensors and whatnot, but I think the major aspect here is going to be dimming based on the viv's internal temperature.

 

[jamma2342]

Its generally 12 hours in the winter and 14 hours in the summer.