hey everyone, im new to the forum but really need some help. i have no electronics experience other than taking stuff apart and putting it back together when i was a kid. i am trying to make something but cant figure it out. i have my kids little toilet that when he pees in it it sings to him. i want to make something out of it. i am trying to make it so that when it is tripped it will start a small dc motor. i cant for the life of me figure out how to do it. i will post a picture of what it is i dont know if that will help or not. if anyone has any suggestions on how i can use this for this or a way to make a simular item i would greatly appreciate it. thank you so much

 

I would guess that on the other side of the board, there is a small glob of hard black epoxy. (not the epoxy but what is under it.) If so, that is the real brains behind your device. Short of using another circuit to sense when this one makes noise, not much you can do with this one. Probably be easier to start over with a liquid sensor circuit that will run a small motor.

 

If the transducer (noise-maker, loudspeaker) is accessible, you may be able to use its drive signal to provide a starting pulse for your circuit. Think monostables. Years ago, I did something of this kind to link an electronic doorbell to an electromagnetic bell as an extension.

Before you ask, I do not have a schematic, and in any case the circuit was built using discrete transistors I happened to have lying about. It is probably not a circuit to be proud of either, but the bell still rings today.

Once you have a logic-level pulse of appropriate length, use it to drive a logic level MOSFET to switch the motor.

 

BillB3857, you are right about the epoxy, it is there. so there nothing that i can do to make this work?

Adjuster, the speaker is exposed. i am not familuar at all with what you are saying to do, do you know what i would need to use to do what you are talking about, some kind of idea of where i would need to start looking for pieces for that. orrrrrr, how hard would it be to make my own to do what i need it to do? anyone know how i could do that?? thanks for the quick replies

 

how would i make a circuit to turn it on when it makes noise??

 

No more help, anyone? I could really use some help. I would pay someone to help me with my problem if anyone would be interested!

 

You will need to provide the voltage level of the audio signal. This may be difficult without an oscilloscope.

You also need to provide the motor ratings.Voltage, current, etc. Does it have to change its direction?

 

Nope I don't need it to change directions. All I need it to do is make one revolution then stop. If I need one of those things I will go get one if it will help

 

1. Motor ratings?

2. One revolution: How do you stop it? Does it stop automatically via an end switch?

3. What voltage is available to power the additional circuit?

4. Will the loudspeaker also be necessary or only the motor?

More details always help.

 

motor says 1.5. i dont really care though. as for how it is going to stop, i dont know how it is going to stop. the little thing that i was trying to use sings for about 5 seconds i was thinking i was going to have to gear the motor to where it would make one revolution by the time the little song stopped. im not set on any one way for it to work as long as it does what i need. i would like it to have a little recorder on it like those birthday cards where you push the button and record your own message as well but first and formost i want to get the motor working. for voltage, i would like it to run on 4 AA bats.

 

motor says 1.5. i dont really care though. as for how it is going to stop, i dont know how it is going to stop. the little thing that i was trying to use sings for about 5 seconds i was thinking i was going to have to gear the motor to where it would make one revolution by the time the little song stopped. im not set on any one way for it to work as long as it does what i need. i would like it to have a little recorder on it like those birthday cards where you push the button and record your own message as well but first and formost i want to get the motor working. for voltage, i would like it to run on 4 AA bats.

You do not provide enough details. For component selection it is of course important to know the motor ratings. It is also important to know what signal triggers the circuit.

Anyway, here is a circuit that you can adjust to your needs. Since you don't know the audio signal frequency or amplitude it's the most easily adaptable I can think of.

V2 is your audio source. The output of U1A goes low when the audio signal peak is higher than the voltage set by R1 and R2. The output retriggers the 555 as long as the audio source is present. In this circuit R7 and C8 are chosen to give an uninterrupted pulse at the output as long as the input frequency is higher than 300Hz without pauses, i.e. you may need to adjust these values.

The output Mosfet has to be chosen according to the motor rating.

 

im sorry that i cant provide more info about that motor. i picked it put at a local hobby shop and the box is in chinese or something, can read one single word on the box. i think when i got it the guy told me it was 1.5 volts but again i could be wrong. so this diagram that you sent, can i take that to a local store and they could provide me with all these parts? is there a book i could read that would help me to understand this stuff a little bit? i thank you very much for your help. it means a lot to me that you are trying.

 

If you took the parts to a hobby store that sell components over the counter they should give you what you need... like maplin (in england), just hand them the parts list and your sorted..
as for the understanding, you might want to just glance over the e books at the top of the page.
http://pfnicholls.com/electronics/monostable.html
have a look at this, it might help, bottom of page is a 555 monostable circuit design...

Hope it helps
Adam

 

so this diagram that you sent, can i take that to a local store and they could provide me with all these parts?

Yes.

You should also buy 2x 100nF ceramic capacitors and a trimpot (potentiometer) 100k and a veroboard/stripboard.

 

For sake of argument, let me ask, could the OP skip the included PCB altogether and just use the probes? Connect one probe to ground and use a pull-up resistor on the other? Connect the probe with the pull-up resistor to a monostable 555 with an edge trigger? Any harm in doing that?

Adamf001, may I ask how fast you want the motor to spin or does it matter much? May I ask what you're doing with the motor? Curiosity on my part. For one revolution, you might want to use a motor gear box kit which will save a lot of time and effort. Something like this: http://www.tamiyausa.com/product/item.php?product-id=70189.

At 8400 RPM (no load I'm sure, so slower in reality) and a gear ratio of ~661:1, you'll get about one revolution in 5 seconds. Hobby stores often carry these gear kits or something similar.

 

elec_mech, that is exactly the kind of motor that i am using. the one i have is still a little to fast. its gear thing is only down to 336:1, i dont think it will matter much. i am trying to design something out of my kids little potty that talks to him. i know its a crazy idea but my kid is a reader. he learns a lot easier by getting into stories. i want to change his toilet so that when he pisses in it it tells him a story. crazy i know. i want the motor to turn the pages of a book that i have built into the back of it. i know it sounds super crazy and difficult but i already but i already have everything designed except the electric part of it. thats why i want to use one of those cards that you can record your message on so i can record part of the story on it so when he pees it will turn the page and tells a part of the story. i am having a really hard time potty training my boy but this method really works for him

 

praondevou, i have all the component that you have in the diagram and a bread board. i am going to put it together now (i hope), the issue is that everyone that i got the components from said the diagram is incomplete. i don't know, i have never done anything like this. oh, and the part that you said if for the sound, no one seemed to know what that is so i dont have that. i dont understand where my power is going to come in from. can you help me with this as i go. or anyone else that is online right now?? thanks guys

 

i want to change his toilet so that when he pisses in it it tells him a story. crazy i know. i want the motor to turn the pages of a book that i have built into the back of it. thats why i want to use one of those cards that you can record your message on so i can record part of the story on it so when he pees it will turn the page and tells a part of the story. i am having a really hard time potty training my boy but this method really works for him

That's a different story now. So we actually don't need the music playing. As others proposed a simpler method would then be to just use the probes and make a circuit that senses directly humidity.

How do you know that this method would work if you didn't built the device yet? I hope you don't do all this in vain. And he's gonna learn it anyway one day, right?

 

praondevou, i have all the component that you have in the diagram and a bread board. i am going to put it together now (i hope), the issue is that everyone that i got the components from said the diagram is incomplete. i don't know, i have never done anything like this. oh, and the part that you said if for the sound, no one seemed to know what that is so i dont have that. i dont understand where my power is going to come in from. can you help me with this as i go. or anyone else that is online right now?? thanks guys

The "part for the sound" is the loudspeaker. (V2 is the loudspeaker, I put it in there for the simulation to work).

Before you burn your circuit: What is the power supply of this thing you have? The same 6V you want to power the motor circuit with?
Do you have a multimeter?

Your power comes in from the 6V you mentioned.

 

The "part for the sound" is the loudspeaker. (V2 is the loudspeaker, I put it in there for the simulation to work).

Before you burn your circuit: What is the power supply of this thing you have? The same 6V you want to power the motor circuit with?
Do you have a multimeter?

Your power comes in from the 6V you mentioned.

forgive me for my stupidity on all of this, if you mean by how many volts the toilet thing that i have is then it has 3 "aa" batteries. i do have a multimeter. im not sure what you mean by your second question. do i want to use that to power the thing i am building, is that what you mean? if so, i have no preferences as to how it is powered. i would just rather it run on batteries than be plugged in. so all the stuff i got for the other diagram you posted, i dont need that now? well i am going to try to build it anyways for practice. do you think there is an easier way to do what i am trying to do? and the reason i think it will work is because his grandpa has a thing that kinda does the same thing but it is something to do with his crazy stamp collection and he is crazy good at it so i thought why not use the method to teach him to do something else that i am trying to teach him thanks again for your help with this i really appreciate it!