Project 9 pinwheel question

Official Hardware Kits Starter Kit
1

Hello.

I have a question related to the motorized pinwheel sample project.
Why would the motor/wheel spin so much faster when directly connected to the 9v battery, as opposed to when it's connected up according to the project 9 plans & code?

I don't see what would limit the motor when it's apart of the whole arduino project.

If I just take the motor by itself and directly connect the 9v it does spin much faster.

I wonder if I can get that same speed from the project? I'd like to! Anybody know

-Bob

2

Is a NPN transistor used to turn the pinwheel motor on & off? If so, it uses some of the voltage so there is less to turn the motor vs direct from battery.
Try changing to having battery+ to motor to relay to battery-.
Or use a N-channel MOSFET with low Rds, which will very little voltage drop across it also.
AOI-514 is a good one.

3

I'm using the project 9 setup. Looks to me that nothing is between the 9v and motor while connected to the arduino & board. In the #9 setup, a simple switch turns the motor off & on. Well, a press of the switch tells a transistor to close its connection. I'll attach a screenshot.

image.png
image.png2048×1536 448 KB

4

If it's not a logic level MOSFET, it won't turn on fully from Arduino 5V signal, and then voltage drop across the transistor is what gets you.

5

Okay thanks! The transistor came with the arduino starter kit.
It's the IRF520.

Specs are here: IRF520 Datasheet

Do you think that transistor is the reason for the drop? I don't know what else could be!

6

I ordered the AOI-514 (a few of them) and that was exactly what I needed to solve my problem.
So thanks again!!! I'm thrilled!

-Bob
:slight_smile:

7

hi im stuck on project 9 have followed the wiring diagram and when i put the irf520 in line nothing happens with the switch if i use a bc5478 the motor runs without the switch being activated. any idea?

8

hertha:
hi im stuck on project 9 have followed the wiring diagram and when i put the irf520 in line nothing happens with the switch if i use a bc5478 the motor runs without the switch being activated. any idea?

Hello,

If you want an answer to your question you really should supply a bit more info to those who are trying to help in this forum.

First of all, try to make normal sentences using capital letters, commas and points. It reads a lot easier and we are able to read it in one go instead of taking 2 or 3 times to let it make sense.

Second. As you wrote, your project doesn't work, or at least, does not what it is supposed to do. As far as your explanation goes now it could be

  • a programming error (no code supplied)
  • a wiring error (no diagram supplied)
  • a component error (ie a broken component, however a small chance it does happen)

I must admit I don't have the book with the projects and/or the starter kit but if it would be a wiring error, I, or therefore someone else who doesn't have the book, could still try to help you.

Good luck