Let's Make Robots!

Hole size on a mini servo horn? (+ where to find hex spacers)

Hi, i've got some miniature servos like this ones :

IMG_0101_0.jpg

and i'd like to know the size of the holes on the horn, but not the center hole, the other ones which are pretty small... Does anyone know what kind of screws i need? M1 maybe?

Actually, instead of screws, nuts and bolts would be perfect for me, do you know if (and where) i can find those at that size?

And i'm also looking for that :

IR LED's. blowing out

The 2 diagrams are cicuits for driving led at 38khz. I implemented both circuits. Firstly i take the second cicuit from the link and just add on the transistor part as seen in the first circuit. I did not add the 4.7kohm resistor nor did i add the 47ohm. Is that the reason why six of my leds are blowing out?

 Infrared555Schematic.gif

OR

the circuit over here http://marwww.in2p3.fr/~levansuu/projets_es2i/Parallax/stamps%20in%20class%20website/downloads/rob4.pdf 

How do people get analog values? (Question)

I just had a question burning in my head. How do people get analog values from thier accelerometers, potentiometers, Sharp infared proximity sensors? How do you guys find those values that you can plug in the PICAXE?

schematics software?

what schematics software do you use?

Best regards from Spain. 

PIC16F690 'delay'

I have spent the past day(i know it sounds stupid) figuring out how to make a 1sec delay on the PIC16F690 to make an led blink. hope you guys can help.

 

this is my code :

*************************************

'

; EQUATES SECTION

 

TMR0  EQU 1

STATUS EQU 3

PORTA EQU 5

PORTB EQU 6

PORTc EQU 7

Battery voltage going down every second

Hello,

What could be the reason that makes the voltage of a 9V battery drop every second? Im trying to build a line-follower robot, and I'm doing the circuit in a general purpose PCB (the one with holes). I'm using a MCU (PIC16F877A) and in the beginning I had only the DC motors connected and it was all good, but after I connected the CNY70 the problems started. The circuit I'm using is:

foo_0.png

Arduino Shield Layout

I am planning to use a simple Arduino Shield for my next project.  I would like to use DipTrace to do this.  Before I start trying to measure distances between pins on the Duemilanove board, I thought I'd see if anyone here has a DipTrace file that could be used as a starting point for a shield.  If so, I'd appreciate a copy.

IF / OR Interrupt? Picaxe...

Hey guys,

I am playing with a 40x2 and the hintsetup and hserinsetup commands also with the flags commands... I would like to interrupt on either a hint signal OR a hserin input NOT both at the same time. It seems that with the various flags conditions, you can stack-up a bunch of stuff that has to be true to interrupt, but there is no "OR" --just a bunch of ANDS

 

Basically, "if hint1=1 and hint2=1 then inturrupt" but not "if hint1=1 OR hint2=1 then interrupt"...

RS232 Communication with MCU

So I am making my own CNC - PCB Miller. It is communicating with the computer using RS232 (UART), but in my testing, I find that I don't always get the correct characters, even at 1200baud. Does anyone have a method to suggest for error-checking an incoming data string over serial? I was thinking of doing something like this:

CPU sends data to MCU 4 times.

MCU checks to make sure the data is repeated exactly 4 times.

--If yes->send "OK" 4 times

--If no->send "NOT OK" 4 times

If CPU receives OK, queue up the next data to send

lcd-routines in avr-assembler

hi everybody

i know that not many of you are programming theit avr mcus in assembler, but i 've got something for those who do:

when i started using lcd displays, i just copy-pated or includet the file "lcr-routines.asm" and used those routines that i found on mikrokontroller.net

I found those routines very helpfoul to start working on lcd-displays.

the other attachment called "lcd_routines_advanced.asm" is something i wrote, based on the existing lcd-routines, but using the srram of the avr as a buffer.

BEC'S as voltage regulators?

When building a robot a regulated power supply is very important to give the controller a good stable 5 volts. Normally a 7805 or better is used. Which is a lineair supply and is very 'proven technologly'. Except it is not very efficient. When used with a battery pack all the volts above 5 are burnt away.

Solution for this is using a switch mode power supply, (buck and or boost regulators). These have a much better efficiency but are less common and therefore much more expensive. Also the ones I found can delivery less than one amp.

PIC16C74B-04/P

I found this 40-pin chip in a CPU battery. It is labeled PIC16C74B-04/P. I have the datasheet, but that's not my best language. i just want to know if its possible to use this as the ones used in LMR - if is possible to make a robot with this chip and what would i need to program it. I read something about ICSP(in-circuit serial programming), which I believe is the process used with this chip, but that's as far as I go. Thanks.

Cardboard Robot Game - starring LMR Look-alikes (rik-puff-calculon-mikv Pyro style !!)

Just for fun i found this game with an uncanny likeness to LMR bods.

including  rik (with Admin-glasses)- puff (the Dragon) - Calculon320 (the robot)- mikv (pyrotechniques).

There are too many synchronous LMR events in this game ....... (did an ex spammer make it !!!!)

THE IR bObOt

hey!

My IR bObOT 

I am a young Algerian of 20 years…. So excuse my language

I build a robot how avoid obstacles with his IR RemoteControl , it was very difficult because I am there where there are anything to create a robot!!, so I use a lot of recovery material 

I am a member of ROBOT PASSION where I exposed my entire project in French 

WOW! thats.. cool?

yes, very!!!  but also scary!

 

In a Swiss laboratory, a group of ten robots is competing for food. Prowling around a small arena, the machines are part of an innovative study looking at the evolution of communication, from engineers Sara Mitri and Dario Floreano and evolutionary biologist Laurent Keller.

Robotics in movies....or at least in an upcoming movie

So this is related to the technology behind a new movie thats coming out. This was originally found on robots.net, a site I highly recommend checking out if you have never heard of it.

I was actually pretty impressed with what they had to show and how far along in the way of robotics we've already come.

In a way this movie reminds me of Ghost in the shell. 

Arduino and Serial communication

Hi All,

Calculon is thinking about jumping onto the Arduino bandwagon, but he has a question or two about serial communication:

- Can an Arduino talk to a picaxe via serial? Calculon understands that picaxe signals are inverted, while Arduino's are "non-inverted"(whatever that is). Is there a way to reconcile this difference? An inverter or something?

- Do the Arduino boards such as the Duicimillanovaililuanne have outpins that can be used for serial communication?

Calculon OUT!

Servos powered by arduino board

Alright, I'm using an arduino pro mini, rated at 5v with a 328. I plan to have two GWS pico servos attached to the board. My power supply for the pro mini is 4 AAA batteries rated at about 1000mah. According to pico servo user the servos have a peak current draw of about 500-550 mah. My question is can my servos be powered directly from my board or must they have a separate power supply. I've asked a few so far and different opinions came up and they told me to start a forum. I could use a different servo with a smaller current draw. I just wanted to get your opinions.