Attiny85 with motor

Hi all,

I'm rather new to electronics,... for stupid questions; sorry in advance! :slight_smile:

I want to create an application with an Attiny85 that drives a small DC motor (5V) running on 4x AA batteries (4.8) + Stepup DC 5V converter. I've added a TIP120 + Diode to protect my Attiny for funny Motor Voltage peaks.

But,... here comes my question; I would like them both using the same power source. Can I just connect my Attiny to the batteries (see the red line in the attachment)? Do I need to add something in between? Capacitors?

Many thanks!

Sander

Hello,

KiwiFreaK:

  • Stepup DC 5V converter

Why bother? Is the motor especially sensitive to the voltage?

Hehe. Thanks for reply. No, not for the motor. Its for other sensors (in the circuit).

I've added a TIP120 + Diode to protect my Attiny for funny Motor Voltage peaks.

Correct placement of the diode...

http://www.thebox.myzen.co.uk/Workshop/Motors_1.html

KiwiFreaK:
Its for other sensors (in the circuit).

By keeping secret which sensors you plan to use you are making it impossible to answer your question.

Can I just connect my Attiny to the batteries (see the red line in the attachment)? Do I need to add something in between? Capacitors?

...so I'm going to go with "maybe".

No, its not about secret. Im still in the pre-design phase. :slight_smile: I am thinking about adding temperature, moisture, soil sensors. I let them out to make it more simple.

About diode: Thanks for the links, i copied my scheme from another tutorial i found.

The circuit: When the diode is placed correctly. Can the + wire be safely connected to the attiny?

Thanks.

Yes.

You need to include a 0.1 uF bypass capacitor for the processor and a pull-up resistor on RESET.

Thanks again, for the reply.

A pull-up resistor for the RESET? You mean Pin1 of the Processor? Connected to ground?

I've updated my scheme (see attachment). Added a capacitor and corrected the diode. Do you think it's a proper circuit now?

KiwiFreaK:
A pull-up resistor for the RESET? You mean Pin1 of the Processor?

Yes.

Connected to ground?

No...
https://www.google.com/search?q=avr+reset+pull+up+resistor

I've updated my scheme (see attachment). Added a capacitor and corrected the diode. Do you think it's a proper circuit now?

I believe you have the battery the wrong way around.

About the pull up resistor, I read there are some discussions about the what kind of resistor. Will 10K work?

I believe you have the battery the wrong way around.

Lol. I'll change it.

Is there anything else I should check?

10k ohms is a good choice.

Thanks for review and advice.

You are welcome. Good luck.