Let's Make Robots!

Servo controller using timeframes

I have four servos with the following specs:


How to click a relay with a low signal?

I need to click a relay when a signal goes low. I have a couple relays on Walter, but they all click when signal goes high. These are pretty straight-forward, just a simple 5v relay, and a 2n222 NPN transistor to click it when a data-level signal goes high. --No Problem

picaxe 12 volt car battery

Hello there!


I'm gettting pretty excited with picaxe and want to start building circuits to control gadgets in my car. So, picaxe circuits all seem to run with 4x1.5 volts batteries ( 6 volts). I want to run them in my car: 12 volts. what is the best solution, and the simplest? (i tought about using those car cellphone chargers that convert 1v to 5.5v, but there is gotta be a better way, right?




Line follow sensor spacing ??

I am a bit embarassed to be asking this but... With everything I have done with Walter, I have never played with a line-follow set up. Now, the electronics I have down solid but I am a little fuzzy on the theory of opperation. I intend to use 4 sensors. Where do they go?


LCD pin names

We have this LCD and we are trying to connect it to the Arduino. We are having problems with the pin names. Here's what we have so far:

Vss - ground

Vcc - voltage (+)

VLc / Vee - we believe this one is for contrast - confirmed

RS : register select

R/W :read / write


D0-D7 : data pins

VB+ : LED positive

VB- : LED negative


LCD - V.Smile Pocket

Would it be possible to make this thing work with a microcontroller? It is from a V.Smile Pocket (handheld brainwash learning station). The V-Tec site says it's a "full-color LCD screen with 320 x 240 resolution". That's all I have.

The white cable is what connects it to the main circuit. It has like 25 metal points/pins. 

[My cell phone camera is not so good]...



splitting voltage

Greetings Earthlings,

Calculon's current project involves 2 12v motors (he's in the big-time now :)) but he'll probably have to use an 18v battery. He wonders what is the best way to power the brains AND the wheels from this.

Should he use a 12v voltage regulator and a 6v regulator at the same time? Or is there a better way to divide up the voltage?

How to connect SPDT relays to control a motor's direction?

I have two SPDT relays, but I don't have much info about them: [a: side label] & [b: top label]

a) 8A - 250VAC

    10A - 28VDC

    DC - 5V

b) Coil: DC 6 9 12 24V

    Capacity: 5 8 10 15A 250VAC

I also have some transistors like this one, some old circuits with various types of resistors, and some diodes too.

How should I connect these things to make a motor change its direction?

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!