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Topic: Uno + Servos + IR Distance sensor = out of my depth? (Read 1 time) previous topic - next topic

waley

Hey guys,

I'm completely new to Arduino, though I've been trying to read up on as much as I can. Also, I realise the best way to learn is to probably just jump straight in and start doing things, but time and money is limited so I'm looking for a few pointers.

Let me set the scene so you can hopefully tell me whether my reasoning is correct.

My is aim to create a robot which can traverse a straight 4.3m (~14ft) path, turn around and come back, whilst remaining within +/-1cm (~0.39in) of the centre-line on the way down and +/-3cm (~1.2in) on the way back. The track has a 12mm rail around the sides of it and is approximately 1.2m (~4ft) wide.

When it gets to the end of one end of the track it needs to move 3 arms (at the same speed) from lying-flat to vertical, and apply about 200grams (~7oz) of pressure at a distance of 60cm (~2ft).

My plan of attack is to use an Arduino Uno with Atmega328 to control the following:
3x 17kg-cm (240 oz-in) Servos -http://www.robotgear.com.au/Product.aspx/Details/421
2x Continuous Rotation Servo - http://www.robotgear.com.au/Product.aspx/Details/482
2x Sharp IR Sensor GP2Y0A21YK0F (10-80cm) http://www.robotgear.com.au/Product.aspx/Details/271
2x 3 Pin JST connector for IR sensors http://www.robotgear.com.au/Product.aspx/Details/274

The top 3 servos will be to control the 3 arms which are required to apply a force. The next 2 servos are to drive the robot down the track and then turn around (they can't just go in reverse, the robot is required to pivot on the spot). I planned to use the two Sharp IR sensors to monitor the robots distance from the side rails and adjust the speed of the 2 drive motors accordingly to keep it running straight. To support the front of the robot I have two ball casters.

This is all going to be battery powered through a pack on the robot.

So if you've been kind enough to read the above, my questions are:
- Do I require anything else to do what I want to do?
- Am I approaching this right way, anything I should know?

I have some limited programming experience and most programming questions I've had I've already found answers for from browsing this forum. Where I trip up is the electronic logistical side of things, so I'm just making sure this is correct before I drop $200 on all these purchases.

I've tried to make this post as clear (and imperial friendly) as possible, hopefully it's not too long :) Thanks!

fkeel

how does it know when it is at the end of the track?

is there any reason you dont use some type of line-following setup? I believe that would be easyer than getting the IR sensors to track a 12mm rail.

other than that, you seem to be on the right track...


waley


how does it know when it is at the end of the track?


That's most probably going to be done with a physical sensor (switch etc.) which will get set when the robot hits the rail to move the program to a second state. I'll tackle that problem once the initial problems are sorted.


is there any reason you dont use some type of line-following setup? I believe that would be easyer than getting the IR sensors to track a 12mm rail.


We are restricted to a starting area so I can't place anything to follow on the track, it would be easiest though.

Thanks for replying so fast.

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