How to make your first robot

Let's Make Robots Tutorials
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841

The Ping is an ultrasonic,

The Ping is an ultrasonic, and it will require different code than the Sharp. There are examples on this site if you search for them.

For tracking, check out the DAGU Compound Eye, which was designed by our very own OddBot.

842

Sensor Alternative

Thanks for your help. I have searched the ping sensor on this site and it seems a little complicated for my level of understanding right now so I may start off with the sharp and then maybe move on to the ping when my skill has increased.

Thanks again

Luke

843

HELP

My components have just arrived and I am eager to begin. However, I noticed that on these insstructions it says I need L293D Motor Driver IC. I have got a L293D stepper motor control/driver.

I used the shout box but they said something about an H-Bridge. I only have basic knowledge of H-Bridges and indead very basic understanding on robots.

How can I sort this out with minimal cost and complication.

Please Help

Luke

844

You have the correct device.

You have the correct device. Inside the Integrated Circuit (IC) chip are two h-bridges.

For more info on what an h-bridge is, have a quick read of the H-Bridge Matrix. That post explains the basics of the h-bridge circuit, which can be used to drive a DC motor in either direction. Some people may want to build their own h-bridge, and that post also provides some great examples.

The L293D chip can be used to drive DC motors or stepper motors. We will use it for the start here robot to drive two DC motors. 

Just follow the instructions in the start here post and you will be fine. 

845

Thank You very much for your

Thank You very much for your reply, I am relieved to hear I do not need to make my own H-bridges.

Thanks again

Luke

846

Seriel Port Error

I have completly built the starter kit to all of your specifications, and downloaded the Programing Editor and the Picaxe usb cable driver to my laptop, yet it still says “seriel port error”.  I have tried all usb ports yet no luck.  The robot does work and computer does also, could it be a faulty Picaxe usb cable?

P.S. : My OS is Windows 7 proffesional.

847

Unfortunately a common problem…

… but rarely is it the fault of the cable itself. There are several posts on this subject. I recommend searching for “picaxe serial error” to find some more info about this.

848

Thanks

I finially got the Programing Editor to function as it should and everything runs fine. 

Thanks for replying!

849

sensor

Hey guys,if you remember i had asked you a question about sensors not working and and 100 tries i just give up i,m planning to buy VIRTUABOTIX ULTRASONIC DISTANCE RANGEFINDER/OBSTACLE DETECTION MODULE .Replacing the older one so can you please tell me how to install it?Please reply and thanks.

850

I never saw you post any

I never saw you post any questions, so maybe it was a question in the shout box? Perhaps you should have posted a forum question. That’s the best way to get help.

Regarding your new request, how about you try to read the documentation and give it a try before you ask for help?  

851

Virtuabotix looks to be

Virtuabotix looks to be selling HC-SR04 ultrasonic modules. Very common sensor. More info here.

Regarding your sensor problems, I agree with ignoblegnome. A good descriptive forum post might net you some info to get it up and running

852

Servo problems

Hi, just starting with robots and love the idea. I have put together the little guy about half way. I’m to programming and I cannot tell if the servo is getting power as it isn’t moving. I am using 3 non rechargable batteries in the 4 slot. I didn’t want to sacrifice my remote controlled car so I instead took a copper wire and soldered it to both a negative and positive connection in one battery slot thinking it may work. Idk! This may be the issue or not. Another thing is that i soldered my pin into the board improperly in the servo 0 slot and instead put one into servo 1 and am using this in programming. Any help would be awesome!

853

Sounds like you’re on your way.

Your modification of your four cell battery holder should work. I’ve done it myself. As far as using output 1 goes, the output pin used doesn’t have to be 0 for the servo to work. One is fine, just make sure to change your code to SERVO 1,position. If I understand you correctly it sounds like you’ve already done this.

When power is applied to a servo it should “twitch” just a little bit. It happens once when you first power it on; it’s just something servos do. You can use your battery pack and some jumper wires to check to see if the servo twitches or not without the PICAXE board involved. If it doesn’t twitch, you have dead batteries or a dead servo. If it passes the test then you need to check the other power supply connections leading to the servo.

Send word of your victory :slight_smile:

854

thanks

thank you for the idea, i’ll test that and tell you my results. here’s hoping the batteries are dead!

855

Simple Interface for Start Here Bot

I got frustrated with the robot starting to run away from me as soon as I put in the batteries so I have slightly modded the code in these instructions to create a simple interface. The robot now starts in a stationary mode when you put in the batteries and doesn’t start moving until you wave in front of the sensor. If you put your hands around the sensor when the robot is moving and hold it there for about 10 seconds the robot will then stop. I have never used Picaxe Basic before so this isn’t very elegant but it seems to work. Thanks and I hope this is useful to folks. Also, I would love to get suggestions from more experienced folks on how to improve the code.  

Symbol dangerlevel = 70 ’ how far away should thing be, before we react?

 

symbol turn = 300 ’ this sets how much should be turned

symbol servo_turn = 700 ’ This sets for how long time we should wait for the servo to turn (depending on it´s speed) before we measure distance

w4 = 0 'this variable will be used to check if the robot has been activated

 

main: ’ the main loop

if w4 = 0 then

gosub checkstart ‘this is a new function to check if the robot has been activated

endif

 

readadc 0, b1 ’ read how much distance ahead

if b1 < dangerlevel then

gosub nodanger ’ if nothing ahead, drive forward

else 

gosub whichway ’ if obstacle ahead then decide which way is better

end if

goto main ’ this ends the loop, the rest are only sub-routines

 

checkstart:

readadc 0, b1 ’ read how much distance ahead

if b1 < dangerlevel then

wait 1

goto checkstart 

else

w4 = 1

wait 1

goto nodanger

goto nodanger

return

end if

nodanger:’ this should be your combination to make the robot drive forward, these you most likely need to adjust to fit the way you have wired your robots motors

high 5 : high 7 : low 4 : low 6

return

 

 

whichway:

gosub totalhalt ’ first stop!

 

'Look one way:

gosub lturn ’ look to one side

pause servo_turn ’ wait for the servo to be finished turning

readadc 0, b1

gosub totalhalt

 

 

'Look the other way:

gosub rturn ’ look to another side

pause servo_turn ’ wait for the servo to be finished turning

readadc 0, b2

gosub totalhalt

 

’ Decide which is the better way:

if b1 > dangerlevel and b2 > dangerlevel then 

gosub totalhalt

w4 = 0

else if b1<b2 then

gosub body_lturn

else

gosub body_rturn

end if

return

 

body_lturn:

high 4 : low 6 : low 5 : high 7 ’ this should be your combination that turns the robot one way

pause turn : gosub totalhalt

return

 

body_rturn:

high 6: low 4 : low 7 : high 5 ’ this should be your combination that turns the robot the other way

pause turn : gosub totalhalt

return

 

rturn:

servo 0, 100 ’ look to one side

return

 

lturn:

servo 0, 200 ’ look to the other side

return

 

totalhalt:

low 4 : low 5 : low 6 : low 7 ’ low on all 4 halts the robot!

Servo 0,150 ’ face forward

wait 1 ’ freeze all for one second

return

 

 

 

 

 

856

How to order in Myanmar/Burma?

$85??? Too expansive!!!  I should order essential parts such as CPU. Battery holder can be tried another way. I want to order things from Myanmar. Which stores should I go? I mean…International Shipping Store near Myanmar. Low cost.

857

$110 again?

Low cost as possible when trainning…

858

rocket ?

Nice … But it s can be a nice bot if  you can send it to the moon :slight_smile:

 

859

Why not ?

Good job ! But why it s do not look like a monkey ? Monkey is good ! Monkey is nice !

860

I understand that the cost

I understand that the cost may seem expensive and parts may not be easily available in your area. However, consider that this list of parts will get you a basic robotic platform with considerable room for expansion. There is plenty of available input/output and processor power to make a more complex project once you have the hang of this beginning project.

Having said that, what are you really looking for? Is this your first robotics project? Are you new to programming, or do you already have some skills? Would a less expensive, but also less capable project be appealing? 

I don’t have any idea of an online store that will be good for your location. Exercize your Internet search skills.