# Circuit design help for blind dog

Discussion in 'General Electronics Discussion' started by JeffJJ, Jan 22, 2017.

1. ### JeffJJ

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Jan 22, 2017
My little tiger is essentially blind due to encephalitis. A quick onset due to an autoimmune response to a vaccine (a possible side effect vets don't often mention). He lived for playing ball (fetch) with a squeaky ball. His prognosis is "guarded" as they say. He's a yorkie and only 4-5lbs. He is my little guy and is in deep depression. He will likely not have enough time for me to train him to adapt to other noises for playing ball (bells, beepers, other noise makers) so hence my problem. The squeak and his size.
My knowledge is limited to electrical (electrician in service for 9 years with basic circuit understanding, resistance, capacitance, transistor, power supply, wiring etc). I have designed and built basic electrical circuits to power devices on my motorcycles and have modified electric guitars etc. So, I should be able solder a design together.
I can envision what I need but, since my knowledge of circuit design (IC etc) is essentially nill, need some help. Any help would be appreciated.
What I feel I need is a device onto which I could record the squeaks of a ball (likely a separate device which I could then remove the recorded info/IC and place into the player circuit. The player circuit would consist of power supply (small battery(ies)), player, micro miniature speaker, timer, actuator for circuit (best thing would be vibration/motion actuation or remote activated that way it could react to my throwing and his shaking and squeak long enough for him to locate...an on/off switch is not very practical tho could be made to work) and a timer (555?).
In operation the device would work as follows: shake/move the ball and it would play the squeaking in continuous loop for say 15-30 seconds.
Now the kicker: the playing device has to fit into a ball with an inside diameter of approx 1.25" (32mm). His mouth is tiny. As I said he is my "little" guy. He used to do flips and rolls and catch the ball mid air. He was more jack russel than yorkie in that way. He lived for playing ball with me and it was something we both loved and looked forward to do.
I would give the sight in one of my eyes to give him his. Yes, he means the world to me.

Thanks for even taking the time to read.
JJ

2. ### hevans1944Hop - AC8NS

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Jun 21, 2012
I think you would be better off putting a receiver in the ball, along with a small piezo-electric speaker transducer. Something on the order of those talking greeting cards but without the recording, substituting instead a small FM receiver. This would allow you to play the audible "hints" at your will using pre-recorded sounds whose duration and repetition you remotely control and transmit to the FM receiver in the ball.

Many FM receiver modules have a "quieting" feature that activates the audio output only when a sufficiently strong FM signal is received. You could use this feature to power down most of the electronics in iieu of an on/off switch, thus extending battery life. If you place a rechargeable battery in the ball, you might be able to re-charge it by inductively coupling energy provided by a night-stand charging station.

The size (1.25" or 35.75mm) is about the same as a ping-pong ball (40mm), right? Will your "little tiger" be able to grasp a ping-ball in it's mouth? If so, you should be able to cut one in half, insert the electronics package, and glue it back together. Else, if smaller size is required, you need to find an appropriate sized hollow ball or make one yourself. I think your project is doable, and it may help extend and improve his quality of life. I am so sorry for your loss.

Harald Kapp and Alec_t like this.
3. ### JeffJJ

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Jan 22, 2017
Thanks and thanks for the info. I had not thought about the small units in the greeting cards...
The balls he normally would play with are a small hollow tennis ball. They barely fit in his mouth (actually sometimes get caught and I have to rescue him). Inside diameter of about 32mm.
Inductive charging is beyond what I was hoping for. I would be happy just to cut open the ball and replace batteries and re-glue. I'll take what I can get.
If it would be easier to utilize an FM transmitter/ receiver (or Bluetooth for that matter), that would be even better. It's just getting the particular sound he responds to...trust me, I've tried other things, he's just programmed to it. Don't think I've ever seen a dog so happy and excited about something.
As I said, any and all info is much appreciated.

4. ### KTW

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Feb 22, 2015
Jeff;
Your dog should adapt to scents to compensate for sight loss.
What do you think about a scented pet squeaker?

5. ### Alec_t

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Jul 7, 2015
I think having a battery inside the ball would be dangerous. If your dog bit into the ball and ruptured the battery, or if the dog's saliva corroded the battery to a point where it leaked, the hazardous chemicals inside the battery could be be very harmful.

6. ### JeffJJ

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Jan 22, 2017
I can understand the concern. I can go by the fact that I have used this particular ball for about 5 years now and he does not have the bite strength or canine tooth length to penetrate the ball per those years of experience. (He is only 5lbs when he's chubbed up, usually just under 4.5lbs). That said, I would be taking the precaution of covering the device in rubber (I use the rubber taping ~1/16" thick utilized for electrical work) and fill any other gaps in the ball with foam. After those precautions the chances of a bite through would be remote at the very best (worst).

7. ### JeffJJ

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Jan 22, 2017
Also, he is never allowed to just play with the ball unsupervised. Or just sit and chew on it supervised. He pulled the squeaker out of one and swallowed it which resulted in a pet ER visit to regurgitate. Even a small squeaker is too big for him.

8. ### JeffJJ

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Jan 22, 2017
I plan on using scent as well. Typical, and in some dogs they adapt to smells quite readily. He is so focused on the sound that he doesn't even try to sniff out. In time I might be able to train him. Time I may not have. In addition, the encephalitis has effected his senses as well including smell or at least the correlation to the direction or location (he will go to his right when he puts his head down). Chemotherapy and prednisone has helped but, we have to be realistic about how good he will be and for how long.

9. ### hevans1944Hop - AC8NS

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2,116
Jun 21, 2012
That's a good point, but unless the power source is a super-capacitor (and how toxic are those?) a battery would be a requirement. That means the whole shebang needs to be potted in an epoxy the dog cannot easily defeat and the play closely supervised. Wireless inductive re-charging is definitely indicated here.

I have had many dogs, mostly in the larger sizes (retrievers, labs, Heinz 57), and I know they will literally destroy rubber toys in just a few hours if given the opportunity to do so. We simply allowed them to do so and replaced the toy when it was no longer serviceable. That could be unacceptable for toy balls with internal parts. Balls with bells or a "squeaker" inside come to mind. Dogs love 'em, but you need to supervise their play. With this app, the OP will be controlling the sound remotely and supervising the play, and so as long as the "ball" is retrieved afterward and stored safely away from the dog there should be no undue concern. Bear in mind that this is a very small dog. Mangling a Twinkie is probably at the upper limit of his capacity harm anything.

Perhaps someone here (I will, if I can find the time to do so) can locate a really small and really inexpensive FM receiver module from among the hordes of eBay sellers, just to get this project moving forward. Bluetooth seems to be a needless and possibly expensive complication, although it has the advantage of possibly playing sound snip-its from a tablet or laptop PC. I did a cursory search of "bluetooth speakers" and found some in the \$60 range, but they are of course way too large. It may be possible to take one apart and stuff the Bluetooth receiver inside a small ball, sans speakers, and then retrofit a piezo-electric "button" transducer in place of the original speakers. Could be an expensive trial-and-error procedure.

If the electronics can be packaged small enough, and the sound made loud enough for the dog to hear, we can then consider inductive charging schemes. That might add a bit of weight to the ball if a small ferromagnetic element (pole piece) is needed to couple sufficient energy through the outer shell for charging.

I have an electric toothbrush somewhere that used magnetic induction to re-charge its internal battery. IIRC, the charger had a little plastic post that fit into a hollow recess in the base of the toothbrush when the toothbrush was placed on the re-charging stand. I am 99% sure that this was essentially a transformer with a large "air gap" in the magnetic path from the primary winding in the base to the secondary winding in the toothbrush. It was probably operating at the power line frequency, 60 Hz, and efficiency was not good because of the large "air gap" separating the primary winding (in the base) from the secondary winding (in the toothbrush). But, hey, it had overnight to do its thing, so efficiency was not relevant. The NiCd battery eventually failed, as they always do, and couldn't be replaced without destroying the toothbrush case, but I kept it around just in case I wanted to open it up to see what was inside.

For this toy ball application, a re-chargeable Li-ion battery would be more reliable, or even a NiMH battery. Almost anything is preferable to NiCd. Just need to "pot" it so that the dog's teeth and saliva can't get to it.