Let's Make Robots!

sensing water flow in a pipe

All,

I remember my dad yelling at my sister and I since we took long showers.  My sister had the hot water turned off more than once on her although I never did.

ganging servos together

I am in the design phase of building a robot arm roughly 40 cm long that can pick up several pounds ( 1 kg for easy math).  To get a 40 kg-cm torque servo is a pretty expensive servo ($60 at pololu.com although anywhere else anyone knows something cheaper, please share!). 

Has anyone ever tried to gang several servos of the same brand and type together to work in concert?  I was going to put a balancing weight on the far end which will help, but still calls for a pretty expensive servo (30 kg-cm)

Ultrasonic HC-SR04 library for AtMega 8 (ie Dagu Mini Driver)

Does anyone know of a library that will work with a Dagu Mini Driver (Arduino NG AtMega 8) and an HC-SR04?  At first I thought I must have two sensors that are dead, but when I hook them up to an Arduino they work fine.

I tried our friend Google, but none of the ultrasonic libraries list if they are backwards compatible to the AtMega 8.  I tried two different libraries and neither seems to work.  I tried different pins, still no joy.

Thanks in advance,

Regards,

 

Bill

 

motor driver suggestions - 6v 6a stall

I am looking for suggestions on how best to drive my Pololulu motors on my MopBot.  This bot is basically a swiffer mop attached to the bot which it pushes around so it requires more torque than the usual small bot I have done before.  These motors are rated 450 ma @6v with no load and 6 A stall.  I am using 6 NiMH AA batteries in series for about 7.2V - 7.5V although could go higher if needed.