Aces High Bulletin Board
General Forums => The O' Club => Topic started by: MickDono on September 25, 2013, 10:36:25 AM
-
Anyone ever had to build one of these?
As my second year group project (Electrical Engineering and Electronics) we have been tasked to build a robot which can follow a line on the floor and also detect an object in its path and stop accordingly. All to be done without a microcontroller.
Now it seems pretty straight forward, my immediate thoughts were to have either LED/LDR pairs or IR emitter/detector to accomplish the line tracking part of the project and an IR emitter/detector to accomplish the object detection.
Was also thinking about using an op amp in comparator configuration with a potential divider / LDR as the inputs and the motor connected to the output. e.g:
(http://img7.imageshack.us/img7/8171/sv6g.jpg)
We were tasked with this project earlier today and these are only my initial ideas. Just wondering if anyone has experience with this sort of electronics and has any advice :) :banana:
-
Seems like an odd place to ask such a question but I'm not complaining. I'm surprised that you uploaded the schematic right away, on the electronics forum I frequent, they usually seem to forget that important detail. When I was in high school I found a blog about someone who tinkered with a similar robot design, I'll see if I can dig that up and post it here. As for your design I have some constructive criticism for you.
The LM324 has minimal output power, you are going to want a current boosting resistor in order to drive the motor. I would suggest using an NPN on the negative end of your motor since it will only have a voltage drop of 0.7V. I would also suggest adding a fly-back diode to the motor since there will be a considerable amount of energy stored in it's coils.
As a line follower having a single sensor isn't going to work (I'm assuming you know this since the 324 is a quad op-amp). Have a sensor on each side of the line and have them look for the floor. The presence of the line will shut off the motor that is controlled by that sensor and the robot will adjust itself. You can also use photo diodes as the sensor since they respond much more quickly to changes in light than the LDRs will.
As for using the IR LED/ transistor combo, I see no reason why that couldn't work. I would think that it will have some trouble with non-reflective objects however. You can have the output trick the motor controllers into thinking that they've seen the line at the same time which would bring the robot to a halt.
I can rummage around through some of my data sheets and see if I can dig up a good medium power transistor.
-
Anyone ever had to build one of these?
As my second year group project (Electrical Engineering and Electronics) we have been tasked to build a robot which can follow a line on the floor and also detect an object in its path and stop accordingly. All to be done without a microcontroller.
Now it seems pretty straight forward, my immediate thoughts were to have either LED/LDR pairs or IR emitter/detector to accomplish the line tracking part of the project and an IR emitter/detector to accomplish the object detection.
Was also thinking about using an op amp in comparator configuration with a potential divider / LDR as the inputs and the motor connected to the output. e.g:
(http://img7.imageshack.us/img7/8171/sv6g.jpg)
We were tasked with this project earlier today and these are only my initial ideas. Just wondering if anyone has experience with this sort of electronics and has any advice :) :banana:
http://www.youtube.com/watch?v=3cShYbLkhBc
-
Seems like an odd place to ask such a question but I'm not complaining. I'm surprised that you uploaded the schematic right away, on the electronics forum I frequent, they usually seem to forget that important detail. When I was in high school I found a blog about someone who tinkered with a similar robot design, I'll see if I can dig that up and post it here. As for your design I have some constructive criticism for you.
The LM324 has minimal output power, you are going to want a current boosting resistor in order to drive the motor. I would suggest using an NPN on the negative end of your motor since it will only have a voltage drop of 0.7V. I would also suggest adding a fly-back diode to the motor since there will be a considerable amount of energy stored in it's coils.
Thanks for the reply mate!
Guessing you mean a current boosting Transistor? I was thinking about this, although i don't have the motor specs yet so all numbers are purely estimates :uhoh
I wondered why most motors have a diode connected to them haha :aok :aok
As a line follower having a single sensor isn't going to work (I'm assuming you know this since the 324 is a quad op-amp). Have a sensor on each side of the line and have them look for the floor. The presence of the line will shut off the motor that is controlled by that sensor and the robot will adjust itself. You can also use photo diodes as the sensor since they respond much more quickly to changes in light than the LDRs will.
Yeah i was thinking of either having 2 sensors inside the line and obviously the corresponding motor would stop when that sensor went outside of the line. or possibly 2 sensors outside of the line. More than 2 sensors seems a bit unnecessary i think. Perhaps for more sensitivity this might be an option.
Great tip about the photo diodes! I will definitely look into them!
-
http://www.youtube.com/watch?v=3cShYbLkhBc
:rofl :rofl