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Adding motor into simple circuit

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Here we go. Sorry about that. I couldn't get an url on my phone earlier.

Thanks for the replies so far
 
Bigger batteries, or separate batteries for the motor and a second reed switch close enough to the first one to be operated by the same magnet. What information do you have about the motor - voltage, current, power, etc?

ak
 
I had thought of doing it with a second reed but not sure if it would work in this application.

The magnet will be attached to the minute hand if a quartz clock and would be used to switch on the sound and motor at the same time.. So not sure how well they would sync.. I'll give it a go though.

I'm not clued up on electronics, so all I can tell you is the motor is a geared one that can operate between 3 and 12v. I was aiming to run it at about 3v DC

Cheers for the reply
 
Reed switches are typically used as sensors and at 500mA max not designed to switch motors.
Use a relay, transistor or mosfet to drive the motor.
You can still use the reed switch to activate the motor driver.
What is the battery bank made up from?
 
Obviously, the battery cannot supply enough current to operate the motor plus the sound module. Use a more powerful battery.
American and European batteries are powerful, Chinese batteries are garbage. Carbon-zinc and Super Heavy Duty batteries are also garbage.
AAA cells produce very low current for a short time.
AA cells produce low current for a longer time.
C and D cells produce much more current for a longer time but some D cells have a smaller C cell inside.
The motor you are using has a minimum voltage of 3V but your 4.5V battery quickly drops to less than 3V.
 
Thanks everyone.

Ok - sound module is an ISD1820
https://www.ebay.co.uk/itm/ISD1820-...535768?hash=item3d1bddf3d8:g:E~wAAOSw705Z4fAf

Batterywise I can use anything I can fit in my clock design.. As long as they're generally available.

I could do it with 2 switches as mentioned prior. I looked at those ir proximity switches, that I think could be used to detect the minute hand..?..

I haven't used them before though, so anyone know if that's feasible?

Cheers

Dave
 
Hi again

I have just been trying to work out those optical switches

Do they simply work as a switch? ie you power accordingly and when they detect a reflection from a mirror for e.g. they put the power through to whatever is connected?

Im looking at the
Vishay TCRT5000 Optical Switch Phototransistor Output

https://rapidonline.com/vishay-tcrt5000-optical-switch-phototransistor-output-60-8260

If this was the case it would be ideal in my application, however my gut tells be they're more complex..
 
No, the internal resistance is higher on the smaller cells, so they cannot deliver as much current.

If you short circuit (not recommended) a D cell might provide 10 Amps, whereas an AAA would not even reach 1Amp.

Bob
 
Thanks Bob.

Im at the level when i haven't digested Amps, voltage etc.. and their meaning..!

So if im running a motor at 3v with a light load on the motor, wanting the best battery life, am I better on Ds or AAAs?

Thanks
 
A large battery cell can provide much more current than a small battery cell. The current drawn by your motor overloaded your battery because the motor is too powerful using too much current that your battery could provide, because the battery was too old or poor quality, or because the battery was too small.

A tiny button battery cell also produces 1.5V, the same voltage as a huge and heavy D cell. But the tiny cell cannot produce much current.

The datasheet of an Energizer AAA alkaline battery cell shows that it can provide a current of 0.5A for a little less than one hour but then the voltage has dropped to 0.8V. It cannot produce much more current than 0.5A.
Their D cell can provide a current of 0.5A for 18 hours, or 1A for 8 hours or 5A for maybe a little more than one hour.

Your motor must have a datasheet that says how much current it uses at 3V when it is working harder that yours will be working.
 

Harald Kapp

Moderator
Moderator
I looked at those ir proximity switches, that I think could be used to detect the minute hand..?..
Not likely, see this discussion.
A photoelectric reflex sensor would work.
all I can tell you is the motor is a geared one that can operate between 3 and 12v.
That is too little information. We need at least the current consumption of the motor when running from 3 V.
If the current consumption is too much for the battery, it will not help to have 2 separate switches as the voltage drop from the motor's current draw will still stop the sound module from operating. You need to make sure that the battery is able to supply enough current for both motor and sound module at the same time.
Even so, chances are that electrical noise from the motor will interfere with the sound module's operation. A filter between the battery and the sound module may help. Use an RC low pass filter made from a small resistor (e.g. 10 Ω) and a large capacitor (e.g. 470 µF).
 
If you aren't too attached to the motor you have already it could be useful to offer up some options you find on the internet that are similar. We can then get an idea of what rpm you require, torque needed (I'm assuming not much, but then we haven't seen your mechanism)... this way we can look at the spec sheet that goes with the motor and work out what is best for you. In the mean time, best of luck.
 
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