Opening Transistor with Arduino

Ok so this is the first Arduino project I have attempted, a simple object avoiding robot.

For the Arduino board I am using an Arduino Uno and for the sensor I am using a LV-MaxSonar-EZ3. I have pulled an old remote controlled car apart to use it as a motor control board (basically a simple duel H-Bridge). You can see the picture below.

I looked online and found the data sheet regarding the logic chip included in this board which has allowed me to isolate the 4 motor control lines and a common line. I have then cut the motor control lines (1,2,3,4) so I can use the Arduino to control the motors.

When I connect a 9V poer supply to the positive and negative leads (as seen in picture) and run a wire from the common to lead 1, it makes the motor spin, going to lead 2 spins it the other way and the same happens for leads 3 and 4.

The voltage going through leads 1,2,3,4 is 2V.

At first I was going to set a separate pin on the Arduino board for leads 1,2,3,4 which would then act as a switch to choose which line was active (needs to at once to go straight). However this brings about a problem with where to run the common.

My question is, can the Arduino be run straight to point 5,6 and the same places on the other H-Bridges (8 in total) and use the output from the Arduino board, along with a 1K resister for protection, straight to these points, opening up the transistor allowing the 9V's from the battery to run straight to the motor. Or would a ground lead need to be incorporated somewhere.

If you guys can see any other way of doing this it would be GREATLY appreciated.

Thank you in advance.

Ps, here is the topside of the board,

You always need a common ground. Not too sure on the rest of it as you haven't posted any links and photos are useless for such a ciruit discussion.

Well what sort of links do you need and I'll be happy to supply them.

The main question is, can a Arduino open the base leg of a transistor...in other words can you have one voltage running through the Collector and Emitter leg (9V power supply) and a second voltage (Arduino) to 'open' the transistor

The data sheet.

You questions are nonsensical and the words you use are all wrong.

Obviously if I had a data sheet, or one was available I wouldn't be coming on these forums to ask a question would I, because I would be able to work it out myself. However I don't have a data sheet hence why I am asking you 'helpful' people a question. If my words and questions are nonsensical maybe you should abandon your attempt to 'help' until someone with enough sense can assist a person who has had no direct education in this area.

"I looked online and found the data sheet regarding the logic chip included in this board

Ok, so you the output traces from that part and now you want to drive the transistors directly. Can you tell what the transistors are?

Was the logic chip bad? Why not just isolate its inputs & drive those>? Can you post the link to that part?

until someone with enough sense can assist a person who has had no direct education in this area.

Ok only got 40+ years in electronics education what do I know. Perhaps a little more than you? Still :)

CrossRoads: Ok, so you the output traces from that part and now you want to drive the transistors directly. Can you tell what the transistors are?

Was the logic chip bad? Why not just isolate its inputs & drive those>? Can you post the link to that part?

Thank you for your civilised response. This link, www.elenota.pl/upload/TX-2B(RX-2B)AY.pdf , will take you to the datasheet of the RX-2B which is the LSI the board uses. Please note it details both the RX-2B and the TX-2B, but obviously the one in question is the receiver.

Yes I want the Arduino to be able to drive the 'opening' and 'closing' of the transistors. Unfortunately due to my 'nonsensical' knowledge I don't know exactly what transistors they are, but from the markings on the side the transistor that make up the H-Bridge have A-1357 inscribed on them, which with a simple google search has told me they are of the PNP style.

The other transistors have C1959 Y 5C inscribed on them.

Grumpy_Mike: Ok only got 40+ years in electronics education what do I know. Perhaps a little more than you? Still :)

Congratulations on your 40+ years in electronic education, one would think if you have had that length of experience in the education field you might know how to help someone a little better than what you portrayed just then.

Count the posts. I help plenty of people here. However the first requirement in getting help is being able to articulate your problem, with a degree of understanding and not a shit load of attitude. If you use words that you make up how do you expect anyone to know what on earth you are talking about. Now I will express your solution through the medium of dance. :P

If your board is wired up like the example circuit on page 7, I would wire arduino output pins to drive the resistors that feed the bases of the NPN transisters from pins 6/7 and from 10/11 (looks like R15/16/7/18). I don't know if you want to drive the Turbo , probably just connect that resistor to ground. Doesn't look like Turbo is hooked up even. See if connecting those resistors to +5 gets your motors going. If you can measure how much current into the resisters when you connect to +5V, even better.

Now I will express your solution through the medium of dance

{ Envisions G_M en pointe, in a tutu. Shudders} :stuck_out_tongue_closed_eyes:

AWOL:

Now I will express your solution through the medium of dance

{ Envisions G_M en pointe, in a tutu. Shudders} :stuck_out_tongue_closed_eyes:

* justjed is waiting for the YouTube link (that is, if it doesn't violate their decency standards) ]:D

CrossRoads: If your board is wired up like the example circuit on page 7, I would wire arduino output pins to drive the resistors that feed the bases of the NPN transisters from pins 6/7 and from 10/11 (looks like R15/16/7/18). I don't know if you want to drive the Turbo , probably just connect that resistor to ground. Doesn't look like Turbo is hooked up even. See if connecting those resistors to +5 gets your motors going. If you can measure how much current into the resisters when you connect to +5V, even better.

Thanks for you help, so I have my board wired with a 9V battery and a lead coming from pin 6 to one of the resisters (to just test) but nothing happens...wouldn't the board need to be grounded to the arduino board?

Crossroads, I have put a lead from the terminal labeled common on the picture above to the gnd pin on the Arduino and it is all working now, thank you very much for your help.

Sorry Crossroads I tell a lie, I did not connect it to the common terminal shown in the picture, I connected gnd to the turbo pin.

Thanks for your help

Way to go 8)