basic stamp in a auto feeder

blessingspoint

I am building a auto feeder for my horse·who is in a pasture with other horses. I am wanting to use the basic stamp for this. I need the basic stamp to run my program only when my horse gets close to the feeder. I was looking for something like a·rf receiver/transmitter. Something that tells the program to run when·my horse sticks it's head in. Any ideas on what will work with the basic stamp that draws low power that would be cheap to build.

Like this.
receiver gets signal
runs servo for pre-determind amount of time
pause for· 30 min.
loops waits until signal returns then starts over.

I am a newbee so I want to keep it simple to start off.

sylvie369

When you say "RF receiver/transmitter", are you suggesting that your horse will wear an RFID tag? It should be fairly straightforward to set up an RFID receiver to recognize that your horse is there IF the horse gets close enough. However, at least according to Parallax documentation, the working distance is going to be a couple of inches, not feet:

ISO Card: 6.3cm (2.5") +/- 10%

World Tag 50mm: 6.8cm (2.7") +/- 10%
World Tag 30mm: 5.3cm (2.1") +/- 10%
Bobsleigh Keyfob: 5.3cm (2.1") +/- 10%
Tear shape: 4.0cm (1.6") +/- 10%

Wristband: 4.0cm (1.6") +/- 10%

This might present a big problem (though I'll bet that·horses are smart enough to learn how to get the tag near the reader if there's a food reward involved, provided things are mounted appropriately).

erco

Sounds similar to the dog/cat doors that require a collar to open. I would start there since someone has already worked out a battery collar transmitter and receiver that last a long time on a small battery.

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·"If you build it, they will come."

SRLM

You'd have a hard time using a regular RF module. Your horse might be on the other side of the field, and the trough opens.

However, you could make an infrared "Beacon" that sends out a code, and a base station at the trough that reads this and opens it. In daylight, an unshielded IR should get at least a couple of feet, but not a fields length.

blessingspoint

2 inches would be a bit tight I would think I need a distance of 12 inches.

I have looked for doc. on the internet about the cat/dog door without any luck finding any info.
and I am not sure it would do what I need I dont really need a door to unlock I need a wheel to turn at a slow speed for a amount of time that is adjustable.

blessingspoint

a infrared "Beacon" sounds more like what I need. would there be anyplace I could get more info on how to build a beacon and the base station and work it into the stamp. I am new to the basic stamp. (just got the Boe-bot in the mail and started reading the book last night but I have built many solar beam bots before so sorry if I ask dumb things.

SRLM

It sounds fanicier that it really is. Mostly, what would consist of is an IR LED hooked up to some sort of oscillator that outputs the 38 kHz needed. Mount this with a battery on the horse, and point the IRLED outward. Then, at your base station just have the reciever constantly looking for the signal. When it sees it, you know the horse is close and you can go do whatever you want it to do. This system is simple, and should work reliably, but there are a couple of things you should consider: the IRLED must face outward, and be visible to the reciever (unlike RF, which is more "omnidirrectional") So, you'll want to choose starboard or port of the horse to stick the IRLED on, and put the reciever on the same side.

Note that you could send out the 38kHz signal to the IRLED with a BS2, but that is complete overkill even to the point of detracting from the setup. So, if you decide to go this route just look around. There's a relatively simple setup with a timer chip of some sort that you can use.

The rest of it you can do with a BS2. There is a chapter in the RwBOEBOT book about IR. Just read on that and you'll see how simple it really is.

uxorious

Well, the perfect solution is an Active RFID setup, but of course that's a little much for your need. (see zigbeef.com/usda_id.html and look at the chute example graphic at the bottom)
With that in mind, why not try to make something that works similar to an active RFID setup? Have a sensor of some sort to detect a horse at the feeder. If that sensor is tripped, then the RF part of the circuit is enabled that verifies the horse AT the feeder transmitting from an RF beacon (or IR beacon). De-tune the antenna on the horse's transmitter limit the range so that your horse must be AT the feeder, not next to another horse trying to steal some food.

Just saw something else on eBay that might be something you can hack or use as an idea starter... cgi.ebay.com/Handbag-Purse-Anti-Loss-Theft-Transmitter-Alarm-Finder_W0QQitemZ230302695980QQihZ013QQcategoryZ115946QQtcZphotoQQcmdZViewItemQQ_trksidZp1742.m153.l1262

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~~ dRu ~~

Post Edited (dRudRudRu) : 10/24/2008 11:38:18 PM GMT

SRLM

I don't think the product parameters call for horse specific horse identification (aka, my horse vs. his horse). So, all that's really need is "does this horse have electronics onboard?" As for telling that the horse is at the feeder, that depends mostly on the physical layout of the area. The ideal setup would be a narrow path with the feeder at the end, and a simple object detection (IR again, ping, pir, etc.) If it's an open area, you could make the IR reciever point in a specific dirrection (with a simple hood), and so the horse has to be right there (in line of sight) to active the feeder.

erco

Unless your horse is sticking his head (with the IR transmitter) into a dark, mostly light-tight box, your IR receiver will be hard-pressed to reliably detect a 38kHz signal in broad daylight. And you'd have to replace a lot of batteries in that IR transmitter to send a signal powerful enough.

A passive IR option which might work is to put reflective material on your horse's bridle. When he sticks his head into the darkened box, an internal IR sensor looks for reflected IR from an internal IR LED. Might take some calibration under various lighting conditions. Instead of a 38 kHz pulsing system, consider a DC light level system. I've had good results in varying light conditions by using a plain old IR phototransistor like a photocell in an RCTIME configuration. Keep sampling the ambient light, which slowly changes during the day, but when the reflective material is seen, it spikes up the reading (relatively) from whatever the ambient reading is.

But overall, RF is a better bet here. No IR or light worries, just a weak (short range) radio transmitter pulsing every few seconds. You will need to monitor the transmitter battery to know when to replace it.

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·"If you build it, they will come."

GICU812

Yea, I think the best solution is going to be one of those remote dog\cat collars, then just wire the output to a hardware timer and a motor, wouldnt even need a controller, depending on the recycle time of the cat collar. Or just use the reciever as an input for the stamp.

IR would work fine even in daylight at shorter ranges <5ft, but you would be changing batteries all the time

Desy2820

What about a pressure mat?· I think they're sometimes used as part of alarm systems.· Place the mat next to the trough, horse steps on the mat, Stamp sees the signal and feeds the horse.

Another possibility might be a load cell,·same idea, the wieght of the horse activates the load cell and signals the Stamp.· Mounting the load cell would probably require modifying the floor though....

The only problem I can foresee is detecting your horse as opposed to any horse.· Maybe a layered system, where the pressure mat/load cell signals the Stamp, which can use a second system·(IR???) to positively ID the horse.· With the mat, you have an idea where and how close the horse is.

Anyway, food for thought.· I hope·it helps.

SRLM

The pressure mat would defeat one of the design criteria:

"to run my program only when my horse gets close to the feeder."

Why not just barcode your horse? Cut the hair in a certain pattern so that skin shows through, then read the stripes? [noparse]:)[/noparse]

blessingspoint

I am going to try out the alarm here are the Specifications:
Range: 0 - 25 meters/0 - 82 feet (without hindrance)
Transmitter power: X1 3V CR2032 button battery
Receiver power: X1 1.5V AAA battery
Transmitter battery life: 3 weeks
Receiver battery life: 2 months
Transmitter dimensions: 4 x 2.8 x 0.9cm (1.6 x 1 x 0.3")
Receiver dimensions: 6 x 3.6 x 1.5cm (2.4 x 1.4 x 0.6")

Will have to find a way to interface it with the stamp and try to ext. batter life the unit can be bigger than it is so adding a AA battery might be my best bet. If I can get like one week out of a AA that would be great but I think it will work .. Thanks dRudRudRu and everyone else. When I get the alarm I am sure I will have a few quistens.

SRLM

Why not have your transmitter use less power by decreasing the range? Since your horse will be in an open field (right?), you can assume that it will transmit 82 feet. What you really want is something more like 10 feet. You can probably increase your battery life more than 15 x (est. since transmission power of waves is exponential with relation to distance). If you keep it the way it is, then every horse within 82 feet of your horse will have access to the feeder.

Ugha

Why not just use a Ping to see if anything as large as a horse gets near? Or maybe a PIR that's been shielded or had its
power reduced or something to limit its range?

Maybe a combo of Ping to check distance, and PIR to check for heat?

Having electronics on the horse is a bit of an overkill... and batteries would be an issue.

If the issue is checking to see if its YOUR horse only... maybe RFID is an option... perhaps something
like a bracelet around its ankle and a reader it has to walk past?

SRLM

Early peoples probably thought that having a saddle on a horse was overkill...

CannibalRobotics

Linx Communications sells little modules that send coded on-off commands like those used for garage door openers. They are not cheap but they would solve the range and coding issue and they are pretty easy to implement. Parallax uses their rx/tx modules in one of their communications products.

http://www.linxtechnologies.com/Products/Integrated-Circuits/

Jim-

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Carl Hayes

Just had a thought --

Is your horse shod? You could have your farrier install a magnetized foreshoe, or one with a magnet in it anyway. It would have to be specially made, because horseshoes are usuallly soft iron that doesn't retain magnetism very well.

Then build a strong pad with one or more reed switches in it. When your horse stepped on the pad, the magnet would close a reed and the feeder would start. No other horse would have a magnet, so only your horse could run the feeder. It shouldn't be difficult to train the horse how to start the feeder by stepping on the pad -- animals have been trained to do much more complex things than that, with food as the reward.

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