I know nothing about electronics I like to be use a TTP223 touch sensor to spin a lightweight 3-inch diameter x 11.5 -inch-long roller tube for 0.75 seconds then stop. The Electric DC motor should not rotate until it is powered. The spin rate should be fast enough to throw a rat’s off balance. (I am making a rat trap) It should run on 4 D size batteries in series which produce 6 volts. Since it runs on batteries ideally when nothing is detected by the only electrical draw is from the TTP223 touch sensor. I suppose the timing could be a 555 CMOS timer but it could be any other design. Can somebody produce a simple circuit diagram to make such a device and the electronic parts needed?

 

Is this for a school project of some kind?

 

It's for my own use. You know your backyard lawn has too many Chipmunks when it's filled with holes like exploded land mines and their running all over the place. My plan is to mount the contraption I mentioned on top of a 5 Gallon bucket. Put a cover over the bucket and dangle the bait along with the sensor from the cover. -- Of course I'll make sure the electronics are waterproof.

 

It doesn't need to be electric - a free spinning roller will do the job.

Available on amazon

 

Set TP223 to be active Low (TOG=0, AHLB=1). This circuit drains nothing when inactive, except TP223.

 

How long does the motor stays on with this circuit?

 

How long does the motor stays on with this circuit?

Tau=RC=100k*10u=1sec

 

An interesting alternative is to use a sensor to detect when the creature is present on that "rolling log", and to operate the rotation motor until the sensor signal switches off because the creature has fallen off. that could be a weight triggered switch or possibly a photo-sensor detecting an interrupted light beam. No timer required.

 

Just put a microswitch at one end and the motor/drive on the other. Support the beam so that it doesn't press the switch on its own. When the weight of the mouse is sufficient to activate the switch the motor comes on. When the mouse's weight has dropped from the beam the motor shuts off. No need for fancy sensing and timing. Just fine tune the system with small springs, something like a spring from a click-click pen. Position the switch so it doesn't take much pressure to activate the motor. Once the mouse falls off - the switch opens up and no power is required to maintain any sort of electronic circuitry.

 

BJJShas provided the drawing of what will work. The mechanical creation will require a bit of effort.

 

The mechanical creation will require a bit of effort.

Either way - creating a motorized rolling beam with electronic sensing would also require some creative work. The motor, drive and beam would be easier to implement but building the sensing method could take more effort. If I were to go that route I'd use an LED and a photo-transistor to switch the motor on and off. But the mouse would have to cross the beam AND you'd need a way to discern the difference between ambient light and the trigger beam. In the dark it wouldn't be a problem. But any sort of light and the motor will run till the battery is dead - providing the power source is a battery. But this would also mean that you would not be able to use the rolling beam in ambient light because the motor would continuously run IF you didn't have some way to discriminate the trigger beam from ambient light.

Easiest approach - put the beam on bearings and let the mice go out on the beam and roll the log. Drop them into a deep bucket. Mice can jump fairly high. A regular 5 gallon bucket won't be that difficult to leap out of. If you get 20 or 30 mice in there then they will climb on each other in order to escape.

Years ago I built a trap door setup to catch mice. Lure them out onto a cardboard trap door. When their weight was enough to overcome the counterbalance they'd fall in and the door would close behind them. No leaping out. But I had to build a small ladder. Plank of wood with carpeting tacked to it.

 

Use a non-stick covering for that crossbar. A lightbeam trigger can work, weight sensing will be better yet, IF you can make it work..