First picaxe robot run

stan74

Senior Member
Hi.I got my first picaxe project working.Didn't behave like I thought.Walls at angles and corners that seem further away than they are and reflections.
easy to mod in basic.Quick to test.Lots of fun :)
I posted a video on youtube https://youtu.be/P55xOf76EPA
 

erco

Senior Member
Terrific! You never hit any obstacles. Congrats!

What a great first PICAXE project. With all the extra I/O on that 28X2, you have plenty of room for expansion. Go Ebay!
 

stan74

Senior Member
Yes erco,bargains abound,especially if I can wait 3 to 4 weeks for something from China but I prefer UK suppliers and only 3 days wait.
The chassis has encoder wheels and sensors are only £1.50 but better,slower motor/gear boxes are first item on the list.
I used pics 15 years ago,messy assembler stuff.I should have tried picaxe.I'd heard of it and basic stamp but thought it was for school kids.
 

stan74

Senior Member
Here's the code in progress.Problem is-
If a wall is ahead then check random right or left is clear if right is clear then
turn right until front sensor clear which won't be much because the beam is now reflecting away
so then check left sensor until left is clear then go forward but now front could be blocked
What makes things worse is I'm using all sensors when going forward because of obstacles at non right angles.
Bats manage ok.
 

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erco

Senior Member
I'd heard of it and basic stamp but thought it was for school kids.
A lot of those school kids are smarter than me already!

Problem is- If a wall is ahead then check random right or left is clear if right is clear then
turn right until front sensor clear which won't be much because the beam is now reflecting away
so then check left sensor until left is clear then go forward but now front could be blocked
A nice alternative to three U/S sensors is one sensor rotated by a servo. You can scan for an exit in all directions even while you're sitting still.
 

stan74

Senior Member
Hi erco.I've seen many bots that use a servo to pan for obstacles.They need to stop and look around but look more "roboty" Ha Ha.I'm ordering some servos later today but I've never used one.I was put off by the mention of timed pulses,etc. but I'll figure it out from code examples. I've got another 5 US sensors coming tomorrow.
The problem with IR or US sensors is the beam bouncing away from an obstacle like approaching a wall not at a right angle.The wall disappears :)
The strip board for my US bot was from an infra red picaxe bot that went to fast for the sensors range.I'll post a photo when I can shrink its size to allow posting.The IR 38KHz was B.0 pwm to 3 IR leds via 220R each to A.0,A.1,A.2. Send them low to light led.Each led had a 3 pin tv type IR receiver with a pin that went low when 38KHz detected.Range was 8 inches.If I had 3 opto isolators I could have used trannys to up the led current..maybe more range.
I must buy a "Dremel" type hobby tool with a mini circular saw and drill bits.
 
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