DC motor

[picpicpikapika]

Hi, I am now trying to drive dc motor using mcu...
I have tried to use 2n2222 npn transistor and 2SD882 transistor to interface between mcu and motor...
My motor is able to rotates smoothly if I use a 12V dc motor...
but I when I change it to tamiya car dc motor, it won't works any more...
Why it is not working, shouldn't the power requirement for the tamiya car dc motor is smaller???

* I am using the dc motor attached in the tamiya car twun gear box set. Thanks a lot

[ABSF]

Which DC motor did you use?

http://www3.towerhobbies.com/cgi-bin/wt ... =CKA&V=TAM

I just took one of the cheapest motors and get its specs:

SPECS: Normal Voltage: 7.2V
Current: 2.85A
Length: 1.2" (31mm)
Diameter: 0.95" (24.2mm)
Shaft Diameter: 0.078" (2mm)

Is your PSU able to supply a current of 2.85A at 7.2V?
Is your 2SD882 able to stand a current of that high without overheating?
What is the voltage across the C/E when it is conducting?

Allen

[picpicpikapika]

Hi,
the motor that I am using I think is similar to the motor in tamiya twin gear box (I cant find from the site that you directed),
your site also got sell,
http://www.cytron.com.my/listProductGroup.php?pid=LwkXCR0aGzYEMS8aBT0IJc7beAAHcYLgvKKtPrb7dFc=

Is this motor require so high current, even more than a 12V dc motor?
When I try to use the tamiya dc motor, my mcu is not functioning anymore, all the led that I interface to my mcu become very dim, and it is like most of the power is sucked by the tamiya dc motor, but the motor is not turning.
But when I change the motor to a 12v dc motor everything is working smoothly, what is the problem??
I need to use the tamiya dc motor because I need to use its gear box, other type of dc motor i think cannot fit into it.
thanks a lot

[ABSF]

You need to provide a link or more details to your 12V DC motors and the Tamiya motors you used. You cannot assume every one in the forum knows what you're doing!!!

Allen

[shiyan]

You need to provide a link or more details to your 12V DC motors and the Tamiya motors you used. You cannot assume every one in the forum knows what you're doing!!!

Allen

Agreed!

[picpicpikapika]

Hi, sorry for the incomplete information...actually I also don't know what type of tamiya motor is this, but from what I know this motor is suit for 3V voltage but is able to sustain up to six volts...

Anyway, I have tried to substitute the transistor to a L293d motor driver, it works already, the tamiya dc motor is able to rotate smoothly but quite fast...

I have another question here, is there any circuit can be used to maintain power?? I mean can maintain a constant supply power to my circuit for maybe twenty minutes without consuming too much of power??? There is a mcu, IR sensor, dozen of LEDs and two tamiya dc motor in my circuit... Thanks a lot...

[kl84]

I have another question here, is there any circuit can be used to maintain power?? I mean can maintain a constant supply power to my circuit for maybe twenty minutes without consuming too much of power??? There is a mcu, IR sensor, dozen of LEDs and two tamiya dc motor in my circuit... Thanks a lot...

I don't really understand what exactly you want to build... Maintain power means..? One thing to keep in mind is that how much power your system draw is depending on the power consumption of the system itself. If your power source fails to supply enough power, your system fails too. In order to reduce power consumption, ppl build low power chips like this. So you have to optimize your system to make it a power saving system.

However, what you mean from "maintain power" is to stabilize the supply, you will need regulation at the power source before you connect it to the system. Anyway, please clarify first...

[picpicpikapika]

Hi,
Actually I am building a mcu controlled racing car using dc motor as the actuator...beside running forward, there will be a few movement for my car(like making u turn)...so the accurate timing is very important...if the battery voltage is decreased sharply while the car is running, I think the car will run out of track...

I am thinking of paralleling two nine volts battery to my regulator input...if i am doing so...in reference to the regulator schematic in the DIY project 4(the project in your site), how can I connect it...do I need another diode, or just parallel it?
Thanks a lot

[shiyan]

Want to power a pair of tamiya motor with 9V battery? Not for 2 minutes I would say.

I don know how much these motors suck current, but how do you get 6V from 9V battery? From regulator? As kl84 said, the load decide power consumption. In you case, 20 minutes is mission impossible with a pair of 9V battery, even 2 pairs(4 units) of 9V battery. 9V battery is not suitable for this setup, it is used in low power devices such as sensor, remote control, multimeter, where the current only take mA, uA, or even nA. And many of these devices are not active for 10 minutes.

Imagine your tamiya motor sucking 1 to 2A compare with mA

Most of mobile robot will use LiPo, especially RC fans.

[picpicpikapika]

Hi,
yes I am using 7805 voltage regulator to supply 5V to my motor...
Wah, even one pair of 9V battery can only drive a few minutes ah (Is it possible to sustain for five minutes?? It is enough for me if it can stand around five minutes)...
So, can the lipo battery be found easily in the market?? Is it expensive?? I have try to seach in the internet, and the size of the battery is quite big, is it difficult to interface to my hardware??
Thanks a lot...