Let's Make Robots!


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Walter's eyes... And the Winner is...

 After coding and reviewing all of the entries, Kari, our (temporary) flatmate Eliza and myself have made a decision.

The winner is rik with the "I forgot my glasses" entry. --rik, you have been on a roll...


***Original Post***

Yup, I'm a lazy bastard...

If any of you folks find your self bored, drunk or both and you have a minute, why don't you help me design Walter's eyes.

Here's the Rub:

You can use any ASCII letter or symbol.

RC RF directional beacon

I am still wondering if it is possible to create a simple, cheap, fairly accurate, directional beacon for outdoor use. And I keep thinking I should try to re-purpose an RC transmitter. So here it goes:

Would you deem it possible to create a directional antenna for an RC transmitter?

Would this antenna be able to rotate? Fully continous, or just 360 CW followed by 360 CCW?

Which RC system would you consider? There are so many frequencies in use. And modulation types.

IR picaxe upgrade problems


i got the infra-red upgrade pack and i connected it up and copied and passed the example code and i keep getting a message: ("infrain" command not supported - use irin!) but when i replace infrain by irin it doesnt work ether .

anybody got any ideas?



Here is the code :

shaping polymorph using paper templates

After two weeks of cutting paper and cardboard, I cannot help but wonder:

Would molten Polymorph soak a piece of paper? Has anyone tried this yet? Think of all the hot applications!

8ik (just ordered half a kg)

My Arduino code question

I have all the makings for my bot and as I assemble it I have been trying to write the code myself instead of copying and pasting but have run into a problem.  Could someone explain why this bit of code doesnt work like I think it should. = )

int motorPin = 4;
int inPin = 2;  
int val = 0;    

void setup() {
  pinMode(motorPin, OUTPUT); 
  pinMode(inPin, INPUT);   

RC control for a Tamiya Tank Kit??

Hi all. Not sure if this is the best place for this question but I figured you might be abe to help.


I just bought a Tamiya Tracked Vehicle Kit with the twin motor upgrade. It comes with a wired controller but I’d like to be able set it up as a true RC vehicle. I’m not looking to spend too much money on this, I just want to work on creating my own chassis for the tank and to control it remotely like any other RC car.


Motor control




I'm building a robot based on my old RC-car and an arduino. The motor-control in my cars is "mechanical" where a servo switches the motor on/off etc. I would like an electronic motor-control instead...and i'm pretty lost.

Do you know a simple motor-control that will make the motor go forward,  just for a start? ;)

I think my motor draws a lot current so L293D is out of question..


Live and Neutral wires

I don't get it, why are these two different (live and neutral) ? Wouldn't the fact that the electricity alternates make them the same thing?

compass modules?

Does anyone know of a compass module that'll return heading as a voltage, rather than timed pulses or requiring an i2C interface? The qwerk board seems a bit limited in its inability to handle either of those, and the api doesn't support the quadrature encoders either so I'm trying to find a way to work out where the thing is facing!

Expanded PVC vs Foam Board

I got some Foam Board from Michaels yesterday and was looking up expanded PVC also to build my robot frame and body. They look almost identical online. Both can be cut with knives also. Are they the same thing? and if they are not the same thing would it be better to make the bot first with the foam board then use it as a pattern to cut the expanded PVC?


Thanks for your help! :)

Joystick and picaxe 28X1


Here is a pick of and old joystick from a 360 or ps controler,

I have 2 questions, the thigs on the side that sens the position are they potentiometer ? and would a chip like a picaxe or some other one be able to interpret the signal coming to it ?


Make robots talk.. to each other.. dirt cheap!

UPDATE: More info on the subject here: http://letsmakerobots.com/node/5194

Original post:


I have this thing in the back of my mind that "the next step" for me must be my robots talking to each other.

LMR Plataform

I just recently resgistered for LMR. It called my attention the plataform is been used here. I have used wikis before but this look a bit different. Anybody could tell me wich plataform or CMS are using here, I am courious.



Help with 18x Electric Vehicle code

I'm working on some code for an event in Science Olmpiad in New york, the code below should check input 2 for a high signal, then jump to sub Diselect, then check for the pins for the right combonations of inputs to then jump to the assosiated sub, the subs take a plse input from an optointerupt and record the length of the pulse to w0, it wil pulse the servo until w0 is equal to the assigned number.



reading from a Sharp GP2D120


 Using an ATmega8, and i'm having trouble reading from my sharp GP2D120.

Here's the code i'm using, which is from the manual of my kit:


So I haven't built any robots lately because I am really busy. But, just a day ago a friend sent me a whole pack of transistors, resistors, and a heck load of ICs. There are about 10 types of ICs he gave. Each having about 20 for each IC. I was wondering if I could use these in any robots but they just are to complicated. I tried searching on google and I really don't get that stuff. Could any of you help explain some of these ICs? Here is the tour through all of them:


The SN74HC74N-


Hi guys. I have to admit i do not know much about these kinds of transistors... i mean, their difference.

I have to get a large current pass through a wire, but after having read articles on wikipedia about mosfet i don't really know why i see them on, say, motor drivers instead of BJT transistors. One thing i don't know about is whether you can find logic-level high-power BJTs but i know there are logic-level FETs, like the IRLD series. But again, if you want to switch a BJT on fully then maybe you could just arrange them into a Darlington i guess.


 Hi all,

You probably read my blog and know I am working on a design for robot legs inspired by the legs of Theo Jansen's Strandbeest.

Below is a picture of a plywood prototype on its way to become version 6.

Robot range measurement!!!

I am trying to get a distance reading from Sharp GP2Y0A21YK0F Infrared range finder. I used the following code to get the distance reading;

readadc10 0, w2
let w2=w2+1
let w2=6500/w2
let w2=w2-4
let w3=w2
debug w3
goto main

I am getting a fluctuating reading, the distance reading seems to vary +/- 7cm from the actual value. I tried to ground the unused ADC inputs but still the problem is the same. If anyone have any experience on this please help.
Thanks in advance