1
\$\begingroup\$

I am controller a DC motor with Raspberry 3 via a breadboard. It works very well. The aim is to open and close a door of a chicken coop.

My issue is that the motor does not have enough power.

If I directly power on the motor, it is turning faster and it has a strong torque. When it goes with the breadboard, it is less.

Do you think this is normal ? Maybe the jump wires does not conduct the electrical current enough ? Do I need to get rid of the breadboard when using it in production ? By soldering all pieces together ?

\$\endgroup\$
4
  • \$\begingroup\$ Show your circuit. "Normal" cannot be determined without a circuit. \$\endgroup\$
    – Andy aka
    Jan 17, 2018 at 13:17
  • \$\begingroup\$ Specifically, the "breadboard" presumably has some kind of power switch for the motor. That power switch is probably key to the problem but we haven't a clue what you're using to do the job. \$\endgroup\$
    – user16324
    Jan 17, 2018 at 13:20
  • \$\begingroup\$ Sorry, I am using this electronicshub.org/wp-content/uploads/2017/08/… execpt that the transistor is powered by the Raspberry PI. I did not draw my own diagram yet.. \$\endgroup\$
    – fallais
    Jan 17, 2018 at 14:04
  • \$\begingroup\$ You can also see this one that is nearly what I do : cms-assets.tutsplus.com/uploads/users/228/posts/20051/image/… \$\endgroup\$
    – fallais
    Jan 17, 2018 at 14:06

1 Answer 1

5
\$\begingroup\$

Breadboard is prone to unreliable contacting, so that's my first guess.

Also, yes, cheap jumper wires are relatively thin (if you can afford to do so, cut one and count the strands...).

Furthermore: motor control might involve high frequencies. Breadboard has high parasitic capacitance and inductance, it's known for bad adjacent-trace crosstalk. So, that might be breaking your system, especially if it involves MOSFETs.

I, very often, recommend that anything that reaches a more than ten pin complexity is modularized and implemented on soldered perfboard. The prototyping of the not-as-complex modules can happen on breadboard!

Point is: If you have \$N\$ contacts to be made on breadboard, and your circuit only works when all contacts are proper, then there's 1 case where your breadboard circuit works, and \$2^N-1\$ cases where it doesn't.

Now, if all contacts have the same "properness" probability \$p\$ independently of each other, then the case that all work is \$p^N\$.

If \$p=99\%\$ (which would be, especially for cheap breadboard, be a good value, as far as my experience goes), then your "works" probability for a circuit with \$N=10\$ contacts is only around 90.4%. For \$N=25\$, it's only around 77%, and for \$N=100\$, only around one third. So:

Abandon breadboard for anything that has complexity. Especially if motors might vibrate, put stress on contacts, or require reliable or high current delivery.

\$\endgroup\$
3
  • \$\begingroup\$ +1 For the reliability statistics! If one imagines that a breadboard mounted Arduino (like the Pro Micro) has 24 pins, then the reliability numbers goes towards zero quite fast. \$\endgroup\$
    – MrGerber
    Jan 17, 2018 at 13:47
  • \$\begingroup\$ Thanks, so you are on the side of soldering all components together instead of using breadboard in my case right ? I won't be able to create my own print circuit I guess, I do not know how to create/buy it. \$\endgroup\$
    – fallais
    Jan 17, 2018 at 14:31
  • \$\begingroup\$ And, electrically speaking, if everything is soldered, my motor will receive all the power right ? (minus the physical loss of course) \$\endgroup\$
    – fallais
    Jan 17, 2018 at 14:49

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.