Dear DAVID Community,

In 2016, DAVID and this forum have been integrated into HP Inc.
This forum has been read-only since then, and will be switched off by the end of 2019.

To everyone who has contributed here, we thank you for all your work and for the constructive, helpful and friendly atmosphere you have created!
Please continue to discuss on the HP Support Forums.

Need some help with a circuit

Need some help with a circuit

Postby 01i » Mon Nov 08, 2010 10:48 pm

Hi,

I am intending to create an automated scanner using a hacked robot arm (http://luckylarry.co.uk/arduino-project ... robot-arm/)

I intend to modify the system slightly, so that I can improve the wrist motor into a 0.9 degree stepper (Nanotec ST4209S1006-B) and for the turntable an 18 degree stepper (SP1518M0204-A)

Adding the steppers means I'll need an extra H-Bridge (Texas Instruments SN754410NEG4) from the Larry circuit, and - I assume - a shift controller (Texas Instruments CD74HC595M)

I may include an LCD display eventually

I've made up a basic diagram of how I think the circuit ought to look, however I dont know enough about controlling power levels with resisters etc.

Could somebody help out by letting me know what I need to add to the circuit, or point me to an online circuit testing tool that I can design it with

Once complete I'll post design info, pics and code in here

Image
01i
 
Posts: 6
Joined: Tue Nov 02, 2010 11:25 pm

Re: Need some help with a circuit

Postby JD_Mortal » Tue Nov 09, 2010 3:32 am

Well, resistors are not good for controlling power-levels, unless that is a last resort. (Higher resistance causes more heat, causes more resistance, causes failure, under any steady load.)

There are shields you can use, since you have an arduino.

I suggest this driver-board... You would need 2 for your diagram layout, 2 stepper, 4 DC (Note, this is for smaller load servo's, <1.2A, can be modded for higher amps.)
http://www.robotshop.com/adafruit-motor ... duino.html

Features:
• 2 connections for 5V 'hobby' servos with high-resolution dedicated timer - no jitter
• 4 H-Bridges: L293D chipset provides 0.6A per bridge (1.2A peak)
• Thermal shutdown protection, internal kickback protection diodes.
• Can run motors on 4.5VDC to 36VDC (separate power supply)
• Up to 4 bi-directional DC motors with individual 8-bit speed selection (~0.5% resolution)
• Up to 2 stepper motors (unipolar or bipolar) with single coil, double coil or interleaved stepping.
• Pull down resistors keeps motors disabled during power-up
• Big terminal block connectors to easily hook up wires (10-22AWG) and power
• Arduino reset button brought up top (Diecimila/Duemilanove only)
• 2-pin terminal block and jumper to connect external power, for separate logic/motor supplies
DIY laser-line, Hand sweep scanning, Generic driverless webcam (640x480), Cardboard background rig, Adequate results.
User avatar
JD_Mortal
 
Posts: 22
Joined: Fri Nov 05, 2010 4:01 am
Location: USA, Florida, Jacksonville


Return to Hardware

Who is online

Users browsing this forum: No registered users and 1 guest

cron