Cat toy circuit board confusion and button dilemmas

Thread Starter

Gina2209710134

Joined Sep 14, 2022
9
Hi everyone, I’m very new here and I’m currently working on a very small project that seemd as if it would be simple at first but is proving to be harder than expected with little to no tech knowledge as of yet. It’s a project for my cat & new kittens. They have a laser cat toy that turns on when you push the button and runs for a bit then automatically goes off again and I want to change the button to a touch capacitive sensor that sits flat so they can turn it on by themselves while I’m out of the house so they don’t get bored. The current switch in the system is a 4 pin switch that is very small in the middle of the switch board. 688A8F30-0919-431B-818A-762BD4C27AE6.jpeg
I’ve looked into capacitive touch sensors but I can’t figure out what I need to attach to where and if a touch sensor would even work with this circuit board. I’d also need to somehow attach a larger surface to the touch sensor so that it would be big enough for cats to understand what they have to do and have it work every time. Is any of this possible and ,if it is, how should I go about doing it? If it’s not, are there any good alternatives?
 

Irving

Joined Jan 30, 2016
3,127
Hi Gina,

Welcome to AAC.

The switch in the centre has 4 pins, but arrangd in 2 pairs connected together so effectively there are only 2 pins. The first job is to work out which 2. The switch almost certainly either connects something to ground, or connects it to a positive voltage. You need to know which to be able to override it. Looking at your switch its almost certain the long direction (horizontal) is the switch ie pressing the switch connects the LH pair to the RH pair..

If you have a test meter it is easy to determine both of these. With the meter set to DC Volts and on a suitable range (assuming its not auto-ranging), touch one probe to a pin on the left and the other to the pin opposite on the right. This should show a positive value above 1 or so volts which will go to 0v when the switch is pressed. If its a negative value, swap the probes over. If no voltage shown, try a vertical pair and swap probes around if necessary. Whichever pair works label the pin with red probe 'pin 1' and the one with the black probe 'pin 2'.

Next, put the black probe on the battery - connection, being careful not to short it out to the +, and the red probe to pin 1 of the switch.
1. If the meter reads 0v on pin 1 and reads a voltage when pressed then the switch is a pull up, pin 1 input, pin 2 to supply, else go to 3.
2. If the meter reads a voltage on pin 1 that goes to 0v when pressed then the switch is a pull down, pin 1 input, pin 2 to ground, else go to 4.
3. If the meter reads a voltage on pin 2 that goes to 0v when pressed then the switch is a pull down, pin 2 input, pin 1 to ground;
4 if the meter reads 0v on pin 2 and reads a voltage when pressed then the switch is a pull up, pin 2 input, pin 1 to supply,

Next, check what voltage is supplied by the battery. If its 5v or less then great. If its more, then things got a little more complicated. Assuming its 5v or less then follow the below...

Now we know what the switch is doing we can wire in a touch sensor. I suggest one of these TTP223 sensors:. You can connect a wire to the touch pad (see the hole bottom left corner) and to a bigger pad if need be.

1663171693217.png1663172112874.png

Now for a little soldering. Disconnect the battery and motor connectors and remove the board from the toy. Run a thin red wire from VCC to the battery + on the back of the board, and a thin black wire from GND to battery - on the back of the board. Run a thin wire from sensor out to whichever was the input pin determined above. Ideally you should remove the switch as pressing it with the sensor attached could damage the sensor. Now, if the switch was a pull down you need to link the two pins at A on the sensor with a blob of solder, but if it was a pull up you need to make sure these are unlinked. Put everything back and test.

If the battery is more than 5v then we need to find a source on the board for VCC, but thats for another time.

Hope that helps.
 

Dodgydave

Joined Jun 22, 2012
10,485
Looking at the switch it looks like it connects top pair to bottom pair ( as the top pair are connected to the same track) and i think it pulls the trigger pin down to the negative rail as the leds cathodes are on the same track.
Get a multimeter and check the supply and switch contacts.
 
Last edited:

Irving

Joined Jan 30, 2016
3,127
Looking at the switch it looks like it connects top pair to bottom pair ( as the top pair are connected to the same track) and i think it pulls the trigger pin down to the negative rail as the leds cathodes are on the same track.
I confess I didn't look that hard, but on closer inspection you could well be right. However, as a learning exercise for the TS I'd make no assumptions and go through the procedure outlined to validate that.
 

ElectricSpidey

Joined Dec 2, 2017
2,161
I'm not trying to dissuade you from the cap sensor approach, but I would suggest a different approach.

Instead of a cap switch you might consider a larger mechanical switch in parallel with the existing tactile switch. (avoids some possible tricky electronics)

Maybe something like a micro switch with an extra long handle, modified for a cat's paw.
 

Thread Starter

Gina2209710134

Joined Sep 14, 2022
9
Hi Gina,

Welcome to AAC.

The switch in the centre has 4 pins, but arrangd in 2 pairs connected together so effectively there are only 2 pins. The first job is to work out which 2. The switch almost certainly either connects something to ground, or connects it to a positive voltage. You need to know which to be able to override it. Looking at your switch its almost certain the long direction (horizontal) is the switch ie pressing the switch connects the LH pair to the RH pair..

If you have a test meter it is easy to determine both of these. With the meter set to DC Volts and on a suitable range (assuming its not auto-ranging), touch one probe to a pin on the left and the other to the pin opposite on the right. This should show a positive value above 1 or so volts which will go to 0v when the switch is pressed. If its a negative value, swap the probes over. If no voltage shown, try a vertical pair and swap probes around if necessary. Whichever pair works label the pin with red probe 'pin 1' and the one with the black probe 'pin 2'.

Next, put the black probe on the battery - connection, being careful not to short it out to the +, and the red probe to pin 1 of the switch.
1. If the meter reads 0v on pin 1 and reads a voltage when pressed then the switch is a pull up, pin 1 input, pin 2 to supply, else go to 3.
2. If the meter reads a voltage on pin 1 that goes to 0v when pressed then the switch is a pull down, pin 1 input, pin 2 to ground, else go to 4.
3. If the meter reads a voltage on pin 2 that goes to 0v when pressed then the switch is a pull down, pin 2 input, pin 1 to ground;
4 if the meter reads 0v on pin 2 and reads a voltage when pressed then the switch is a pull up, pin 2 input, pin 1 to supply,

Next, check what voltage is supplied by the battery. If its 5v or less then great. If its more, then things got a little more complicated. Assuming its 5v or less then follow the below...

Now we know what the switch is doing we can wire in a touch sensor. I suggest one of these TTP223 sensors:. You can connect a wire to the touch pad (see the hole bottom left corner) and to a bigger pad if need be.

View attachment 276231View attachment 276232

Now for a little soldering. Disconnect the battery and motor connectors and remove the board from the toy. Run a thin red wire from VCC to the battery + on the back of the board, and a thin black wire from GND to battery - on the back of the board. Run a thin wire from sensor out to whichever was the input pin determined above. Ideally you should remove the switch as pressing it with the sensor attached could damage the sensor. Now, if the switch was a pull down you need to link the two pins at A on the sensor with a blob of solder, but if it was a pull up you need to make sure these are unlinked. Put everything back and test.

If the battery is more than 5v then we need to find a source on the board for VCC, but thats for another time.

Hope that helps.
Thankyou so much this definitely helps a lot!
 

Thread Starter

Gina2209710134

Joined Sep 14, 2022
9
Hi Gina,

Welcome to AAC.

The switch in the centre has 4 pins, but arrangd in 2 pairs connected together so effectively there are only 2 pins. The first job is to work out which 2. The switch almost certainly either connects something to ground, or connects it to a positive voltage. You need to know which to be able to override it. Looking at your switch its almost certain the long direction (horizontal) is the switch ie pressing the switch connects the LH pair to the RH pair..

If you have a test meter it is easy to determine both of these. With the meter set to DC Volts and on a suitable range (assuming its not auto-ranging), touch one probe to a pin on the left and the other to the pin opposite on the right. This should show a positive value above 1 or so volts which will go to 0v when the switch is pressed. If its a negative value, swap the probes over. If no voltage shown, try a vertical pair and swap probes around if necessary. Whichever pair works label the pin with red probe 'pin 1' and the one with the black probe 'pin 2'.

Next, put the black probe on the battery - connection, being careful not to short it out to the +, and the red probe to pin 1 of the switch.
1. If the meter reads 0v on pin 1 and reads a voltage when pressed then the switch is a pull up, pin 1 input, pin 2 to supply, else go to 3.
2. If the meter reads a voltage on pin 1 that goes to 0v when pressed then the switch is a pull down, pin 1 input, pin 2 to ground, else go to 4.
3. If the meter reads a voltage on pin 2 that goes to 0v when pressed then the switch is a pull down, pin 2 input, pin 1 to ground;
4 if the meter reads 0v on pin 2 and reads a voltage when pressed then the switch is a pull up, pin 2 input, pin 1 to supply,

Next, check what voltage is supplied by the battery. If its 5v or less then great. If its more, then things got a little more complicated. Assuming its 5v or less then follow the below...

Now we know what the switch is doing we can wire in a touch sensor. I suggest one of these TTP223 sensors:. You can connect a wire to the touch pad (see the hole bottom left corner) and to a bigger pad if need be.

View attachment 276231View attachment 276232

Now for a little soldering. Disconnect the battery and motor connectors and remove the board from the toy. Run a thin red wire from VCC to the battery + on the back of the board, and a thin black wire from GND to battery - on the back of the board. Run a thin wire from sensor out to whichever was the input pin determined above. Ideally you should remove the switch as pressing it with the sensor attached could damage the sensor. Now, if the switch was a pull down you need to link the two pins at A on the sensor with a blob of solder, but if it was a pull up you need to make sure these are unlinked. Put everything back and test.

If the battery is more than 5v then we need to find a source on the board for VCC, but thats for another time.

Hope that helps.
Update! So I got a meter tester and tested everything and here are the results. 58B47AFF-19D2-4FA0-8338-37FDD5486025.jpegAnd it is a pull down switch I think cause it seems to fit scenario 3. I understand where I need to connect the wires on the ttp223 sensor but I’m not sure about the battery positive and battery negative part. Do I connect to the battery directly to the battery pack or to pin 1 and 2? And if pin 1 and 2 would I be right in guessing that the red pin in positive and the black pin is negative? And also which one is the input pin? Sorry for all the questions im still getting the hang of this.
 

Thread Starter

Gina2209710134

Joined Sep 14, 2022
9
Update! So I got a meter tester and tested everything and here are the results. View attachment 276262And it is a pull down switch I think cause it seems to fit scenario 3. I understand where I need to connect the wires on the ttp223 sensor but I’m not sure about the battery positive and battery negative part. Do I connect to the battery directly to the battery pack or to pin 1 and 2? And if pin 1 and 2 would I be right in guessing that the red pin in positive and the black pin is negative? And also which one is the input pin? Sorry for all the questions im still getting the hang of this.
Never mind I just realised I was testing it completely wrong and now I’ve done it right I know exactly which one is which. Thankyou so much for all your help tho, honestly couldn’t have asked for a better explanation.

<EDITED TO REMOVE SPURIOUS QUOTES AND THEIR TAGS, MODERATOR>
 
Last edited by a moderator:

Irving

Joined Jan 30, 2016
3,127
Never mind I just realised I was testing it completely wrong and now I’ve done it right I know exactly which one is which. Thankyou so much for all your help tho, honestly couldn’t have asked for a better explanation.
Which is?
So did you check battery voltage?
And the red/black wires go to the solder joints for the battery connector on the back of the board.
 

Thread Starter

Gina2209710134

Joined Sep 14, 2022
9
Which is?
So did you check battery voltage?
And the red/black wires go to the solder joints for the battery connector on the back of the board.
Okay I think I may have figured incorrectly then I was planning to take the button off and just solder it the the same points. The bottom two are positive and the top two are negative I’ve figured out after making the mistake of testing it without it plugged in. Also there aren’t any metal bids on the back of the board apart from where the lights connect does this matter?
 

Irving

Joined Jan 30, 2016
3,127
Ah, I see your dilemma.

Assuming the battery is 5v or less then the red and black wires to the sensor are as shown below. The blue wire is the output from the sensor.

1663362369844.png
 

Thread Starter

Gina2209710134

Joined Sep 14, 2022
9
You're welcome.

Incidentally, what is written, if anything, on the two 8-legged devices?
Okay so nothing easy to read but on one of them there is writing. From what I can read it says:
TRA9116
FA87 2899
20181107…
The last one has a bit more but I can’t read it. I did take a picture through a magnifying glass that turned out okay. E31411B8-5B04-4F79-A727-BEFA2352D21E.jpeg
 
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