Let's Make Robots!


Minimal Picaxe LED blinker

I just found a different way to make an LED blink with a picaxe 28x1:

   inc b0
   let pin7 = b0 >> 7
   ' do other important stuff here
goto main

Learn how to use your Arduino, and blink an LED
Hello all! In this walkthrough, I'm going to show you the basics of the Arduino and how to blink an LED. I know this has been done many times, but since I'm hoping … Read more
his head is an LED and turns on only when there is no light !
Not only does he look human , he is also a functioning circuit ! his head is an LED and turns on only when there is no light ! he has got a mind of his Own ! :) … Read more
Emits bright light and loud noises =D
Around the end of February every year there's a 'Chinese Lantern Festival' that happens in my city. Lots of junk to buy, cool lanterns, interesting food, and most … Read more
Lights up when it becomes dark and lets you get in bed without breaking your feet or furniture in the bedroom :D
This is my little LightBox, a night light. Basically what it does: When you switch off lights, it lights up for a minute for you to reach your bed without accidents … Read more
Simulates firefly synchronization
First off all, apologies for the lack of video. Read more
I had some RGB LEDs lying around and decided to make a night light for my kids. Read more
Plays musical notes using a non-contact LED stylus.
This is 'Allura' - a small synthesiser I built as a platform to test out a few techniques for another project in progress. Read more

Luxeon Leds - what would be the simplest constant current driver for them


I have just bought 5 of these 3W High-Power LEDs 

I could drive them off batteries direct ....

...however i would prefer to feed them with a "constant" but adjustable (350mA-750mA) current.


What would be the simplest circuit i could use ?.....

.... and would there be a way to PWM them?. 


Specs :-

3W High-Power White (6000-7000K) 130 Lumens - 140 deg

Brings good tidings... until nightfall. Then it signals the mothership for the invasion!
Merry Christmas or the secular, religious, or pagan holiday of your choice. I love this little Christmas ornament from Instructables, so I decided to build some … Read more

More info than you'll ever want to know about current LED technology

This is a great read if you like knowing about the current technologies going into the components we use to build our bots or other gadgets. It's heavy on the technical info just as an fyi. 

While reading it I was also surprised to find the company that makes those luxeon LED's have some damn cool tech.




When using an LED formation, with a picaxe and added sensors, servos, and motors that is powered by four AA batteries, does that change what the source voltage for the LED formation would be? And would it be possible to add this LED formation to the start here bot at one of the output pins so you could control the blinking of several LEDS instead of one at a time. Or if there is a better way to accomplish this could you please enlighten me?

Zodiac display done.

Edit: Added some more photos to the bottom. Those were taken with the curtains shut. Also took a short video.

Finally completed the zodiac display. Aside from the sickly colour of the top and 1 of the red LEDs stopped working after I glued it all together, I`m pretty happy with the way it turned out.

Edge lit zodiac display.

The school I work for runs extra Summer School classes over the summer break here in Japan and all the teachers are given some certain amount of freedom in how they teach the curriculum. Everyone is encouraged to make displays, signs, games etc. Basically let your inner child out and make some cool stuff :)

Part of what I have to teach is the western zodiac. The section in the kids textbook was really lame and everyone knows LEDs make things 100x better so this is what I have come up with... the LED-edge-lit-zodiac-star-sign-display!!

Heres the basic plan:

can i still add a laser, speaker, led?

in my robot SC-QR-1 i have allready used all 8 servo-ports.

but can i still ad a laser(to see where it looks), a speaker(for it to call hor help or showing some sound-emotions..   etc.) and some leds(like a red to show power, white/bright to help my "primary-back-mounted-not-night-vision-spy-camera") 

and if yes would the servos disturb the lasers, speaker and leds?

and i was also thinking, stuff like the sharp ir sensors have ir leds in them, could i attach an led or laser to those pins??


please reply!! :D

LED configuration for PICAXE 'Testing the System'

Hello everyone. Ground-zero beginner here. I've been a programmer for maaaaaaaaany moons, and I'm using robots as an excuse to learn about electronics. It's strange, yet fun to be a complete newbie again ;)

Some parts are on their way and I am spending my time deciphering the picaxe manual. One paragraph confused me and I think I finally figured it out, but I would like to have confirmation.

 It's in picaxe_manual1.pdf in the 'Testing The System' section when it describes the LED connection:

Blinking an LED in about 5 to 10 minutes

Earlier today got a FedEx delivery of a MakerShed order placed last week. Toys!


 One particular toy was a new Arduino Duemilanove. Had to see what made the Arduino popular.


A tutorial for calculating series resistance and reading LED data sheets
I've noticed that some people are uncertain how to calculate series resistance for a LED or when using a group of LEDs are uncertain about wiring them in series or … Read more

LED String

Hey All,

Let me present my next round of noob question to keep you all on your toes....

I'm trying to add AmandaLDR to my next project. Two eyes in front, two on the bottom for edge detection. The problem is that digital outs and space for wires are limited, so I was hoping to combine my SuperBright LEDs into a single output if at all possible.

When I connected the anode of one LED to the cathode of the next LED, only the second LED would work. Ditto for the third of 3, etc.

1. Is that because of the forward voltage of the LEDs?

led array

I would like to make an Led array say 5x5 or so but if a wanted to only light these lights

0  0  0  0  0

0  0  0  0  0

0  0  0  0  0

0  0  0  1  1

0  0  0  0  1 

how would i Do it without doing this?

0  0  0  0  0

0  0  0  0  0

0  0  0  0  0

0  0  0  1  1

0  0  0  1  1

Are they flashing really fast of somthing similar?

(0 is of 1 is on)

Thanks for helping 

Led controller

Hi this is an led controller  there can only be one led on at a time it was on crocodileclips i don't know what its called but if anyone does that would be helpful. when A is high 0 is on if B is high 1 is on if A and B are high 2 is on and when A and C are high 3 is on or somthing like that.


picaxe trouble


I just got a new picaxe 28x1 for christmas. I was trying it out and the pins don't seem to be working.

For example:

I connected a led to output pin 3 and ground and uploaded the code


high 3

pause 5000

low 3

pause 5000

goto main

For some reason this code doesn't seem to do anything as the led just stays on constantly. and, yes I did wire the anode and cathode the right way

Is there something wrong with my chip, or am I just doing something incredibly obvious and dumb? 


Navigate around via Infrared Rangers
Using a
1-1-09 Roger has been working like this for a while, but I never went around to make a video of it. Here it is. I added some white LED's as head lamps and that is … Read more
Steps battery voltage up or down.
The MC34063A is an easy to use DC-DC converter that can be used to step battery voltage up or down to run your processor, small servos or to make an efficient LED … Read more

I wish I had enough time to hack my graduation hat like this

I was looking a while back for people that had hacked their graduation cap. I didn't find any links as to how to do it, but one professor actually designed a circuit board to replace the cardboard with some ultra-bright LEDs.

angered his fellow professors something fierce, but everyone else loved it.

link to the story 

SED or Smoke Emitting Diode

This is an attempt to record the very edge to which an LED can be driven. A failed attempt.


I tried to post this as a component page, but it would not take embedded video...

The LEDs I tried are rated at 30 mA maximum. The forward voltage is between 1.9 and 2.1 V. I used a power source of 8.1 V  and a variable resistor in series that could range from 5000 to 0 Ohm.