Let's Make Robots!

Driving One Stepper Motor With L293D Using Two Pins

Question: Is it correct, that when I solder the following circuit there are only two pins nessessary
from the microcontroller to the L293D to drive a unipolar stepper motor ?

Answer: Yes. That is correct.


Question: Are the two NPN transistors and the 10kOhm pull-up resistors responsible for the signal inversion?

Answer: Yes. That is correct.


 

How do you determine pins on relay?

I got this relay today but not sure how this relay works. Try to search on this particular relay but not much information or datasheet. I tried to wire it around and find out if I connect A and B with battery I can hear the TIC sound so I assume C1,C2 will be connected or C2 and D2, however it doesn't work that way. If I connect the battery on C1 and D1 and connect a motor on C2 and D2 the motor will work. So, I guess C1 and C2 is linked and so as D1 and D2.

New LBD geared motor for small robots

DAGU have now released a modified version of our Little Black Duck analog servo.

This is the Little Black Duck servo, modified for continuous rotation with the control circuit removed making it into a simple geared motor with a ball raced output shaft. This motor is perfect for small robots and can be easily driven by an L293D or a controller with a built in "H" bridge such as our Micro Magician.

Help with Micro/Mini Gearhead motors for tiny bot

Ok so if you've read my profile here, one of my goals is to create/produce a low cost, versatile micro/mini robot that could be used as a swarm bot.

Currently I'm trying to source some decent tiny gearhead motors for under $12 dollars. Today I've come across these:

http://goo.gl/H17Wj

and this

http://goo.gl/0U1bf

 

Also there are some 3V gearmotors of the same dimensions with varying RPMs (from 30 to 100rpm) available as well. The torque ratios are not given for those, however.

Capacitors

Hi, can I use in circuit however big capacitor or do you know some article about using capacitors? Thank you.

cheap sources for mini-motors?

I'm putting together a project for school kids, so I need to find a volume source for both small dc motors and servo motors.

Like this one:

http://www.browndoggadgets.com/store/motors/mini-motor/

and the ones found in lumi's ALF project

http://letsmakerobots.com/node/33449

 

Autonomous navigation strategy: how to move forward from basic to advanced?

Last week my Rover 5 completed his first tour in our living room avoiding obstacles / no bumping ;-).

The Rover has the following sensors / inputs:

The Parallella Board?

I was wondering what people think of this board and the supercomputer that this guy built with them.

The Board:

https://www.parallella.org/board/

This guy built his own supercomputer with 8 of them (each with 18 cores) wrapped around a gigabit switch and a couple of Intel I3 NUCs.

The Supercomputer:

https://www.parallella.org/2014/06/03/my-name-is-brian-and-i-build-supercomputers-in-my-spare-time/

Wild Thumper Controller - Packaged Software has Issues

If you are trying to used the Dagu motor controller with their Wild Thumper vehicle, which is great, but can't get it to respond properly to a RC tranmitter, make the following changes to the software. Get off D0 and D1 and move to D9 and D10, which are PWM channels. You don't want a PWM repetative pulses (every 22ms from a Spektrum transmitter) to clobber your serial interface when loading programs. This is why you get a sync error from the compiler if you follow the manual.

Optimized voltage divider for low power application?

Well, I'm (trying) to build a low power node which is powered by a tiny 80mAh NiMH battery pack which in turn is recharged (kept charged) by a small photovoltaic panel.

I want to measure the voltages at both panel and battery, so I'm thinking of using a couple of voltage dividers. Usually I wouldn't think too much on it and would just use a couple of resistors, that would divide the max Vin to the voltage at which my chip would be running. 

In this case I intend to run an Atmega8 (if everything fits -- else atmega328p) at 3.3V...

Picaxe bldc ESC Driver

Hello guys!

I'm brand new to letsmakerobots and newbie of picaxe world...so forgive me for the noob question.

Two Dumb Questions; TX/RX LEDs on TTL and Wheel on Motor

Good evening everyone,

Two dumb questions:

One,

I'm working on getting simple RX/TX traffic indicator lights on a 3.3v TTL system.

 

The LED is a tri-color RGB LED (datasheet).  I'm trying to accomplish something like in this post here, the Olin answer.

Damage Assessment on the Kossel

Well, I ran into my first real fail of cheap parts.  Apparently the RAMPS 1.4 board I bought has two defective mosfets.  I'd like to take the blame and say I blew them, but I was being insanely careful.

And after inspecting the mosfets I've found physical damage to them.  Sigh.

Code help for Robot arm - High current motor

My project is a 5 motor robot arm.  I have a megamoto  plus mega2560.

How to make a medium size robot. Let's make a guide!

Now we have wonderful tutorials for making beginners and small robots, but bigger robot need stronger frame, motors, bigger batteries and can do much more work.

There are good examples of medium size robots here, but it would be useful to me and maybe others if there is a good comparison of various motors and drivers, how to get them and what to care about to avoid crashes and dangers.