# Help with a small project. (new here)

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#### Doc Savage

##### Newbie level 4
hope im posting in the right place. i have a project turning a robot that walks, into one that uses wheels, i need a part that will turn the leg motors that go back and forth into ones that go in one direction constantly. i cant make them go in one diirection by themselves, its complicated. is there a part/component that will do this? i seem to remember the name of somthing but its slipped my mind. if you need further explanation, just say so. any help finding the part i need is greatly appreciated:smile:

#### Nitish Reddy

##### Newbie level 5
Well you need to be a little more specific about that, but as far as i can make of it, its going to be pretty difficult doing what you asked.

Instead you could replace both the leg motors with just one simple DC motor. But you'll have to feed the DC motor with inputs from both the leg motors along with using simple diodes.
A more detailed way of putting it is:
- Remove both leg motors and replace with just one DC motor.
- Now take the input of 'leg motor-1' and connect it to the input of the DC motor via a diode.
- Similarly take the input of 'leg motor-2' and connect it to the input of the DC motor via another diode.

This should feed only positive/forward inputs to the DC motor while the negative/backward inputs are cancelled by the diode.

---------- Post added at 09:21 ---------- Previous post was at 09:11 ----------

OR [ A much less complicated way ]

Assume we ignore/remove 'leg motor-2' altogether and we will use only the input of the 'leg motor-1'.
- Remove the 'leg motor-1' and connect its input to the DC motor via a 'Rectifier Circuit'.
[Should do the trick]

If the voltage to the DC motor is not sufficient enough, you could use a simple 741 amplifier circuit with an external battery as power source.

#### bigdogguru

i have a project turning a robot that walks, into one that uses wheels, i need a part that will turn the leg motors that go back and forth into ones that go in one direction constantly. i cant make them go in one diirection by themselves, its complicated. is there a part/component that will do this? i seem to remember the name of somthing but its slipped my mind.
Are you referring to Servo Motors?

#### Doc Savage

##### Newbie level 4
Well you need to be a little more specific about that, but as far as i can make of it, its going to be pretty difficult doing what you asked.

Instead you could replace both the leg motors with just one simple DC motor. But you'll have to feed the DC motor with inputs from both the leg motors along with using simple diodes.
A more detailed way of putting it is:
- Remove both leg motors and replace with just one DC motor.
- Now take the input of 'leg motor-1' and connect it to the input of the DC motor via a diode.
- Similarly take the input of 'leg motor-2' and connect it to the input of the DC motor via another diode.

This should feed only positive/forward inputs to the DC motor while the negative/backward inputs are cancelled by the diode.

---------- Post added at 09:21 ---------- Previous post was at 09:11 ----------

OR [ A much less complicated way ]

Assume we ignore/remove 'leg motor-2' altogether and we will use only the input of the 'leg motor-1'.
- Remove the 'leg motor-1' and connect its input to the DC motor via a 'Rectifier Circuit'.
[Should do the trick]

If the voltage to the DC motor is not sufficient enough, you could use a simple 741 amplifier circuit with an external battery as power source.

i see whats goin on. ok. but how will i be able to turn the robot then? i was gonna use both motors to kinda fix that. any ideas?

#### Nitish Reddy

##### Newbie level 5
Haha now you've made it very complicated Well you need to tell me how the robot would have turned with its legs. For instance I assumed that when the robot is moving forward, the legs with be alternatively moving back and forth, therefore i was able to tell you how to use the input signals from the Leg-motors to the DC motor. So yeah, how do the legs behave when turning?

---------- Post added at 16:03 ---------- Previous post was at 15:50 ----------

How were you planning on turning the bot? Maybe i could just add a little.

#### Doc Savage

##### Newbie level 4
the legs move just as you described. when you press the controller button to go forward, the motors go back n forth to do the walking. i coulda sworn there was a sort of device that would allow incoming intermittent signals to be smoothed out into a single signal. basically making the motor go one direction instead of going back n forth, that way i could have it turn, etc without much modding.

#### Nitish Reddy

##### Newbie level 5
Ohk I think I got it now... You've removed the legs and have exposed the bare motors right?? I was under the impression the mechanical legs were still in place. Ok so if you have access to the Input wires to the Leg-motors here's what you do.

- Isolate both wires going to the Leg-motors [ Typically they should be red and black ]
- Use a 'Diode Rectifier' to both the input wires [ Diode rectifier is an extremely simple device to make - about ten minutes ]
- The output of the Rectifier will give you Two Output wires.
- Connect these output wires to the leg-motors. [ Voila! The motor should now turn only in one direction ]
[ This way you don't have to add or remove any motors ] [ All you'll need is a diode rectifier which should cost less that USD 1$] Check out the illustration in the picture : https://www.edaboard.com/member429016-albums163-56810t.JPG #### Doc Savage ##### Newbie level 4 Ohk I think I got it now... You've removed the legs and have exposed the bare motors right?? I was under the impression the mechanical legs were still in place. Ok so if you have access to the Input wires to the Leg-motors here's what you do. - Isolate both wires going to the Leg-motors [ Typically they should be red and black ] - Use a 'Diode Rectifier' to both the input wires [ Diode rectifier is an extremely simple device to make - about ten minutes ] - The output of the Rectifier will give you Two Output wires. - Connect these output wires to the leg-motors. [ Voila! The motor should now turn only in one direction ] [ This way you don't have to add or remove any motors ] [ All you'll need is a diode rectifier which should cost less that USD 1$ ]

Check out the illustration in the picture : https://www.edaboard.com/member429016-albums163-56810t.JPG

DIODE RECTIFIER!!!! THAT WAS IT! THANK YOU SO MUCH! oh man i cant wait to build it and i hope you guys can help along the way in my future endeavors! btw pic is a tad small lol:lol:

points: 2

### russel01

points: 2

#### Doc Savage

##### Newbie level 4

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