Let's Make Robots!

Hooking up a Schmitt trigger (74HC14)

I need to hook up a 74HC14 to clean the signal from a QRB1134 IR sensor. I think I know how but I need to make sure. Could it really be this simple:

*Connect pin 14 to 5V (from Arduino)

*Connect pin 7 to ground

*Connect pin 1 to the signal output of the QRB1134

*Connect pin 2 to the Arduino analog in

*Place a .1uF cap between the 5V and the ground wire

Here is the datasheet and an example I used:


TLC5940 anyone?

Allthough these chips are actually called LED drivers they are apparently capable of controlling servos...up to 16 of them :) There is even an Arduino library available for doing so. Pretty cool stuff. But I was wondering if anyone has any experiences with this? If yes then I'd like to know more about it. If not well then consider this a tip to keep in mind the next time you run out of servo pins ;)

NiCad vs NiMH batteries

I wanna buy a charger and some batteries so I've been doing a bit of research on the different types. However the information I found is somewhat confusing and outright contradictory. And in any case I'd like to hear about the experiences you guys have had using NiHM and/or NiCad batteries...

Which would be the better choice? Pros and cons?

Advice on accelerometers

Some questions about accerometers:

1) Which would be a good buy? I am putting together an order at seeedstudio cause they seem to have all the stuff I need at good prices. I'm thinking of throwing in this accelerometer, but I don't know if it's any good? I also saw that polulo has this cheaper model. So which would be the better buy? Or perhaps a 3rd option?

Multiple swithces to analog input?

Just had an idea. I'm planning to use a LOT of (tactile) switches on a walking robot. For instance I wanna put several under each foot. But it seems like a waste of pins to use a digital pin for each switch (or use multiplexers). So I thought I might be able to connect the switches in paralel and read several at a time from an analog input using resistors of different sizes connected in serial with each switch. Like this:


Homemade wheel encoder

Basically I just printed out one of these (laser printer recommended):


...And attached it to a wheel (double sided tape recommended).

Then I hooked up one of these (a 2$ IR sensor: QRB1134):


...And attached it to the motor pointing towards the wheel.

Setting up a QRB1134?

Does anyone know how to set up one of these things:


I can't seem to get it working.

Someone made a quick "tutorial" on LMR but I just don't get it.

I found a diagram here that just doesn't make sense. The wire colors are all messed up.

Then I found this:

I wasn't really gonna post this robot, but then I thought what the heck, it IS my 1st robot. Besides the next time one of you guys make a robot that isn't as … Read more

Environment mapping

I'm currently working on an application for mapping the environment with a range sensor. Right now it's only a sharp sensor (GP2D12) mounted on a servo that is turning slowly, while the readings and corresponding servo angles are being sent constantly to my PC via serial. The program then converts the angle and distance to x/y coordinates and draws a map.