Let's Make Robots!
tc  

Edit: Check out this nice clone: http://letsmakerobots.com/node/8386


From building big, nasty, with large shovel, 2 cores, multiple sensors, soundsystem etc, I got tired of that.. and decided to see what fun I could have with a little Picaxe 8 on a board ($16, total prize for robot is about $40).

Version II of this fella here: http://letsmakerobots.com/node/101

I have since recieved some interest in how to build this extremely easy and cheap robot, and so I hereby transform this post to a small and simple tutorial:


Shopping list:

Can be bought from Picaxe:

You can get this from anywhere:

  • 1 9V battery
  • Some sticks and something to cut them
  • Screwdriver
  • Soldering iron and led
  • Some pieces of wire and something to cut it with
  • Some different types of glue or tape etc
  • a table-tennis ball and a knife to cut it
- And then you need some motors with wheels. I recomend these, used in my robot.

 


I like the challenge of only having 8 pins and 128 bytes of code etc. But be aware; you get a funny robot, but it is blind, can only sense a bumper in front, and you really do not have much memory in it etc.

What I did after building this, was i set it up with Easy Radio serial wireless input on the only pin left for anything. This made it possible to control this little robot by another robot, which opens new windows etc.

Some friends and i in our local club also had a contest of making it draw the number 8 on a piece of paper with a marker glued to its back.. Good fun little fast and chep robot!

 

IMG_3399.jpg
A stick, some switches, and a sliced up table-tennis-sized ball for "the third wheel"

 

IMG_3397.jpg
To get the 9V down to 5V, I use a voltage regulator.

IMG_3400.jpg
I was just mounting with some glue, the strips just tohold things in place..

IMG_3401_0.jpg

IMG_3403.jpg
An angle grinder may look like an extreme tool for such a small job - but I use it quite often. Just turn it on, hold it steady against something, and anything you stick in there is just vanishing, nice and smooth - compared to cutting such small parts. I also use it for acrylic (Plexiglass), again it is perfect to make little cuts and markings.

IMG_3414.jpg

Just follow the instructions that comes with the board - it cannot be more simple, hook up the 2 motors.

The motors I recomend are incredible! Fast and strong, even though I only feed them 3.5V due to the 1.5V drop from the Motor Driver. So I actually had to make a "tale-bumper" (red square) as it was lifting the front a little too much :D With the bumper on it turned out quite cool, as it is just as capable of navigating on only the rear-wheels.. there is nothing else but a glider in front anyway.

IMG_3406.jpg

All needed now is some code and the battery.

TIP: Get rechargeable batteries (and a recharger) - Or you will soon have used as much on batteries as on the Robot itself!

REMEMBER: If you make anything like this, to take a picture and show me :)

Here is the code used in the robot on the video. Don't mind that the names of the sub-routines does not make sense to you. Fact is that nothing in this code makes much sense, it was just the fun I had at the time when I shoot the video :)

I will have a closer look at this soon, but on request, here the code from the video:


symbol fw = 20
symbol bc = 200

b0= 175

''''''

dav:
random w5

for w3 = 0 to w5
if pin3 = 1 then
gosub bum
end if
next w3


b0= b0 +1
random w5
if b0 < w5 then goto hest

random w5
if w5 > fw then
high 1 low 0'ForwardRight
endif

random w5
if w5 > fw then
high 4 low 2'ForwardLeft
endif

hest:

random w5
if w5 > bc then
high 2 low 4'ReverseLeft
endif

random w5
if w5 > bc then
high 0 low 1'ReverseRight
endif

goto dav

bum:
w4 = 32212
return

high 2 low 4 high 0 low 1'Reverse
pause 300
if b0 > 175 then
high 1 low 0'ForwardRight
high 2 low 4'ReverseLeft
else
high 4 low 2'ForwardLeft
high 0 low 1'ReverseRight
end if
pause 300

b0 = 175
return

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fritsl's picture

You should start simpler, you are trying too many things at the same time. It is very common.

Start by making an LED blink, and only that. Make variations, and then move on, and make sure you master the next thing, and only move on once you master what you do and find no more challenges in it.

1220's picture
hey frits! i have ordered the parts for this little robot and i was wondering if there is any way to put on red and blue LEDs on him. the link for those bumper switches are broken for me so ive been searching fo hours for those things. any other site that has those? also the usb cable link is broken and i coudnt find any info on one that would work. I need help plz!
fritsl's picture
I am sorry, but to put it short; These are the litte things that you have to find out yourself.
EEEEE's picture
Hey I was just wondering in the videos how come the robot moves backwards after it hits something and then turns around? why doesnt it turn around right after it hits ? Is it the way the code was written ?
fritsl's picture
Yes, it is how the code is written

Hello, I'm tring to make this robot for a Technology projct, and I was wondering if u can explane sum stuff bout the codes. and how to make it?

Blshook

fritsl's picture
You should read the manuals for the language.

Hey there cool robot. i was wondering if could use this cable (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&Item=350222968722&Category=40059&_trkparms=algo%3DLVI%26its%3DI%26otn%3D2) instead of the one you suggest. It looks the same. if not this one can i use the picaxe serial?

 

Another thing can i use alternative motors?

 

regards

 

ignoblegnome's picture
The Picaxe cable has a circuit in the USB connector head. It is not just translating the pins from USB to serial. So I wouldn't trust that the cable you listed would work with a Picaxe.

ok thank you both 4 your answers