Hi,
I need to activate 2 coin motors at different times and I was planning to use a LabJack U3 and Matlab.
I am not an expert in electronic and the people I have asked for help gave me very different advices; this is the coin motors I am planning to use: https://www.precisionmicrodrives.com/product/310-004-10mm-vibration-moto...
One of my friend said that I should be able to activate the coin motor by connecting to the LabJack's digital output two resistors in series (to break the 5v in 2KΩ and 3KΩ) and then connecting my coin motor in parallel with the resistor that matches my coin motor's voltage.
My other friend instead suggested that the LabJack can't supply enough current to the coin motor to keep it on for a certain duration, hence I should use a Solid State Relay and an external power source plugged to the coin motor and controlling it through LabJack.
I am totally lost, can I get an advice from you?
Many thanks!
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One of my friend said that I should be able to activate the coin motor by connecting to the LabJack's digital output two resistors in series (to break the 5v in 2KΩ and 3KΩ) and then connecting my coin motor in parallel with the resistor that matches my coin motor's voltage.
This might work if you just put 1 resistor in series with the motor, but not really sure. If you put a 167 ohm resistor in series and the motor and it draws 30 mA, 3.5 volts will drop across the resistor leaving 1.5 volts for the motor. You would have to do a little testing to determine current versus voltage for the motor to pick the right resistor and perhaps make this work.
My other friend instead suggested that the LabJack can't supply enough current to the coin motor to keep it on for a certain duration, hence I should use a Solid State Relay and an external power source plugged to the coin motor and controlling it through LabJack.
The motor needs 10-30 mA. The VS terminal can provide more current than that, but is at 5 volts. A DAC output can be set to that voltage, but whether it can provide enough current is questionable.
Do you want to just turn it on & off, or are you wanting to try and vary the motor somehow?
Hi,
Thanks for your reply!
I am glad to hear this is sensible!
So does this mean that I can use the DAC to activate the coin motor but not to keep it active?
I would like to turn on the coin motor, keep it on for a short random duration ranging from 50 to 1000 milliseconds and then turn it off. What is the best way to achieve this?
Thanks again!
Without knowing the exact current versus voltage relationship, the solid answer is that you provide a 1.5V power supply capable of at least 30 mA, and then use the U3 to control some sort of switch that is gating that power supply to your motor. The power supply could be a D battery or any other 1.5V supply you can come up with. The switch needs to be something with low-voltage drop, since your voltage is only 1.5 volts. Probably some sort of fet switch.
If you have a variable voltage source and a couple multimeters, then you could collect some data on current versus voltage for your motor, and also note the minimum level where it runs the way you want. Then we could probably figure out a slicker way to control it.
Actually, I have a better test that might just lead to your solution. Simply connect DAC0/GND to your motor, then use the Test panel in LJCP to start increasing DAC0 from 0.0 up to higher voltages. As you increase DAC0 use a DMM to measure the voltage at the motor to make sure you don't go over 1.5 volts. As the motor draws current some of the voltage will drop across the output impedance of DAC0, so you might find that you have to set DAC0 to 3.0 volts (for example) to get 1.5 volts at the motor.
See DAC specs here:
https://labjack.com/support/datasheets/u3/appendix-a