Let's Make Robots!

Start here kit posted by Frits---- Problem with Motor Driver and Sharp

This is my first robot ever, and I seem to have a problem with the L293D Motor Driver IC and the Sharp GP2Y0A02YK sensor. I bought the kit from Solarbotics. My dad and I put together the (wiring on the) project board, motors, and servo correctly. I downloaded the Programming Editor for Vista and connected it to a computer using the AXE027 USB cable. I turned the servo to center (150). Then, I soldered on the wires on the Sharp exactly like the picture provided. I connected it again, and inserted rechargeable batteries. When I typed in  

main:

readadc 0, b0

debug

goto main

smoke started coming out of the robot. Then, my dad and I disconnected the sensor, and tried commanding the servo to move. It moved! There was nothing wrong with the servo. Then, we tried 

low 4

high 5

and also 

low 6

high 7

but the motors did not turn the wheels. So, we put our fingers on the motor driver, and found it extremely hot, while the resistor array and PICAXE-28X1 IC Microprocessor were cool. So now, we are facing a problem and do not know what to do. 

Thanks again! 

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Hi, I had the same problem with the robot turning slightly all the time. I found that the slow motor just needed a little WD40 (or similar) sprayed into the gear box and it sorted it right out. 

Okay! So I got the motor driver (and motors) to work, and the distance sensor is working well enough to test. I might get a newer sensor with a cable (still learning how to solder). But for now, here is my question.

I mounted my wheels onto my motor. When I turned them on, and set the robot on the ground (without the long program) (just the --

high 4

low 5

the robot would not go straight. It follows a slightly curved path for some reason. How do i fix it? The wheels are still like the ones in the picture.

Thats because the code you are using for testing is just for one motor

high 4

low 5

will drive only one of your motors either the left one or the right one(depends on the pins).

When only one motor is driven the robot moves in a curve not straight.For running the robot straight you will have to use the code for both motors

e.g

high 4

low 5

high 6

low 7

Oh! I am sorry. I had typed in both the codes, but just forgot to mention them in the questions. Yes, I did type in

high 5

low 4

high 7

low 6 

yeah i have an even worse problem you think shorting the sharp is bad well one of fthe traces one my microcontroller got cut (don't know how.) my sharp got chewed up by dogs (puppy) my servos transistors "exploded" (V2 batterys leads turned wrong way) and some of my batteries started spewing acid (bad).

how does that sound?! ;) just be glad you didnt end up like me! ;)

ps getting a new board, metal gear motors, servo hxt900, new sharp and a sharp cable (yes no more nasty soldering!). If you want a cable then go to:   http://www.pololu.com/catalog/product/117  and the new and cheaper sharp here:  http://www.pololu.com/catalog/category/79  cheers! ;)

That is really sad!! I am especially sorry for the Sharp (dogs).

This here is my one single biggest complaint with the picaxe board. This issue is responsible for frying (4) sharps of mine at the same time. Yes, the ADC inputs have the data pin IN THE MIDDLE!! It seems so silly to do this but alas, it is so. Yup, probabaly fried your sharp. I am sorry my friend.

Order another sharp --or upgrade to a SRF05 and while you are waiting, you can play with the servo and motors.

You may also want to check the soldering at the sharp itself --it is a little bridgey --double check for shorts here.

4 sharps ? that is so sad.

Even i connected two of my sharps the wrong way once but luckily nothing happened to them.

You have connected the sensor wire in the wrong series

The red wire should be where the black wire is currently and the black wire should be where the white wire is currently(on the picaxe board)

Like this

Starting from left

Black,white,red(this series is according to the below photo)

it would work if your sensor has not been damaged by the wrong connections

Also see  Picaxe for dummies

 

Thanks Kawal! It works well now!!