I have a question about a project that I want to do. I want to create a box where the lid opens up based on ambient light. Basically the lid closes at night and is open during the day. It will be a wildlife feeder that deters (nocturnal) raccoons from eating all of the feed but allows daytime wildlife to feast heartily. I know very very little about arduino but believe it would be possible to do it using the correct setup. My basic design is to have a linear actuator opening the lid but was also considering a crank type system (similar to a steam engine drive wheel). I need to either be able to control how long the actuator extends when enough light is present and reverse the action when not enough light is present or turn a servo motor with a crank a certain distance. Id prefer to use the actuator since the lid will be about 10Lbs and will need to extend about 10”. Is this possible? if so, how hard would it be for a aduinewbe be to program? Thanks in advance for the advice!!! Ive attached a crude drawing.
Easy enough to read some kind of light sensor, like a light dependent resistor, compare it to a threshold which you would have had to establish by experiment, and actuate the mechanism.
Some linear actuators actually act like servos, and their control is therefore trivial; Firgelli's "-R" models act like servos for example.
the choices were : #1) use an add-on board a RTC or real time clock board.
*PRO: works regardless of weather or sun
CON: sunrise changes daily, it would only be at sunrise 4 times a year without additional programming
(note : I wonder if there is a sketch that is already writing for daily sunrise times )
#2) use the arduino as a clock and just count time
PRO : all software no extra parts
CON : clock must be re-set with the loss of power
#3) a circadian input on #2 above.
note : this would use the average of the last 'x' number of days to start.
PRO : *does not need adjustment for daylight savings time, nor seasonal changes
will 'self-correct' with the loss of power
light not required if it is raining or cloudy
con : possible to loose a whole day after power if it is a cloudy day
my choice would be a combination. the RTC is only a couple dollars and by adjusting start time based on the last 'x' days of sun, it could be made to mimic the seasonal times.
there are many versions of a threaded rod on a stepper, so the application is very possible. For outdoor use, I would use a stainless threaded rod and a large one like a 1/2" dia one.
racoons are very powerful. the threaded rod design would be a clock only where the rod is connected.
a sliding cover might be easier, and when it slides closed, it could have the lid 'captured' so that it could not be lifted.
if you want to prevent squirrels, then putting the works inside of a cage or fence would be the best. small enough that a chipmonk and small bird, but not large enough for a larger animal.
If you can open and close the lid with a string then you can windlass the string with a motor.
Just be sure to have a sensor to know if you're going to trap an animal when closing the lid.
You might put timer code in there so that a passing shadow or cloud doesn't trigger closing time or some kind of flashlight or headlight/whatever doesn't have it opening at night.
You might use several sensors to escape falsing, one small light detector can be covered by one small bird crap or insect.
here is a link to an outdoor threaded rod design. used for heliostats. same principal for your project.
Thinking about the sliding cover, if you did that, you could have the motor and screw under the cover
Thanks to all the prompt replies and idea! Also, thanks to whoever corrected my subject line.
Dave, i love the idea. I plan on installing this at the back of my property (lots of acreage) so i was planning on including a battery and possibly a small game feeder solar panel. The lid will open and close relatively slow (20-40 seconds) giving any critters ample time to get out of the way. Would this be a more efficient design than my original drawing? Can a smaller actuator be used?
Does it actually need to be big enough for them to get in?
How about more like a chute thing that might open and eject a "dose". Or like a dog feeder with a flap that lets the animal eat but worst it would do when it closed would biff them on the nose.
GoForSmoke:
If you can open and close the lid with a string then you can windlass the string with a motor.
Just be sure to have a sensor to know if you're going to trap an animal when closing the lid.
You might put timer code in there so that a passing shadow or cloud doesn't trigger closing time or some kind of flashlight or headlight/whatever doesn't have it opening at night.
You might use several sensors to escape falsing, one small light detector can be covered by one small bird crap or insect.
You’re right. I could eliminate the actuator completely. Ill have to experiment with both designs.
Does anyone have a place for me to start? Board to buy? set up for multiple photocells? some sample code for it? Def a newb at arduino
JimboZA:
Does it actually need to be big enough for them to get in?
How about more like a chute thing that might open and eject a "dose". Or like a dog feeder with a flap that lets the animal eat but worst it would do when it closed would biff them on the nose.
I suppose it shouldn’t have to open more than 6 inches. I’ll need it to feed, squirrels, rabbits, deer and birds so 6 inches would work. Ive seen the automatic feeders and if the animals don’t eat the food then the high humidity at night here will turn it soggy.
I think a previous suggestion about a Real Time Clock's a good idea: timing doesn't have to be exactly dawn and dusk, pick a time for each and off you go. Change it each season if necessary. Photocells introduce all sorts of calibration problems, like full moon or heavy cloud.
I'm pretty sure a Uno's up to the job, or even a smaller one. But Uno is just so handy for prototyping.... Get one anyway and if you don't use it in production then you have the prototyping board for the next project. I'd go for a starter kit, and in your case get an RTC. I have a DS1307 which I got "loose" but in hindsight one wired on a breakout board with the xtal and battery would have been a lot easier.
youcancallmebigdaddy:
Does anyone have a place for me to start? Board to buy? set up for multiple photocells? some sample code for it? Def a newb at arduino
IF you're going to do this yourself then spend real time just learning how to do things and what is possible. That could take months.
IF you're going by help then resign yourself to not knowing a lot of what you're doing.
Spend a lot of time planning and modeling different ways before you buy anything but a development board and some starter components. Even then ... Shop. The only corner you shouldn't cut is to buy the dev board from Arduino to support the IDE and forum. It's a 1-time thing unless you get into having different dev boards.
You won't need much of a processor for what you want but in development a standard UNO should do fine.
The same UNO can be used later to program smaller, far cheaper chip(s) that your final in the field unit(s) use.
No kidding, the UNO main chip runs about $2.50 and can run stand-alone with a few cheap components. An ATtiny costs less but has less pins, memory, flash and not all the capabilities of the UNO chip just to save a buck.
Light detectors are a few for a dollar if you shop but the motor bits depends on how you do it. The UNO can easily trigger a relay that will switch clear up to 10 Amps of 240VAC or a lot of DC on and off so if you can figure out how to work the lid with limit switches and maybe sensors so you somehow don't kill Bambi then you won't need a motor controller and code for that. Perhaps some fail-safe thinking would be in order?
But look and learn first. You can make sensors that will know when any animal is close, like capacitive sensors that will pick up a deer or bigger at 3 or more feet if you tune them right. Acoustic guitar disk sensors (piezo) could tell if something is scrabbling in or at the box.
Infrared leds and pickups to tell if something is between or reflecting off might be good but some animals can see those and might mess with the led(s). And forget ultrasonic distance sensors as they don't work well on hair, fur or wool.
Luck of the draw. The DS3231 is temperature-compensated and is specc'ed at ±2ppm accuracy from 0°C to +40°C. The DS1307 doesn't appear to even have a PPM specification, and anecdotal evidence shows a lot of people have DS1307s that drift several seconds per day. ds1307 drift - Google Search
You might get a good DS1307 that might be pretty accurate if kept at a relatively stable temperature. Or, you might not.
youcancallmebigdaddy:
Can a smaller actuator be used?
The threaded rod will need to be strong enough to withstand the torture from a hungry raccoon.
the beauty of closing lid is that the screw will be impossible to spin without the movement of the motor or some actual tools. Thinking about that, a nut on the end to allow you to open it without power seems like a good idea.
you could use a very small motor for this as the threads multiply the power. I would think that a small gear motor might do the trick.
dave-in-nj:
The threaded rod will need to be strong enough to withstand the torture from a hungry raccoon.
Assuming the animal has to pull on the lid/rod, a 1/4-20 threaded rod has a minimum tensile strength of 1,750 pounds. I hope to heck I never meet a 'coon with that much strength.
