Society of Robots - Robot Forum

Electronics => Electronics => Topic started by: MangoBot on July 24, 2009, 06:52:00 PM

Title: Help with circuit
Post by: MangoBot on July 24, 2009, 06:52:00 PM

OK, so i am making a line follower using a LM393 dual comparator chip and a motor driver, and i was thinking if i could use the $50 robot circuit, except instead of the atmega put in the IC's where it is. The link for the comparator: http://www.goldmine-elec-products.com/prodinfo.asp?number=G32124 and for the motor driver: http://www.pololu.com/catalog/product/24 they will be in sockets. what changes would i have to make?

Title: Re: Help with circuit
Post by: SmAsH on July 24, 2009, 06:53:50 PM

i wouldn't try to use the $50 board... they're too different...
rather make your own. it cant be that hard.

Title: Re: Help with circuit
Post by: apc3161 on July 24, 2009, 06:55:57 PM

The ATmega8 has a built in analog comparator in it that you can utilize. You just have to initialize it in your programming. Check the data sheet for more info and instructions.

I would do this as opposed to using a discrete device for this purpose. This way you get to learn more ATmega8 feature and build up your programming repertoire.

Title: Re: Help with circuit
Post by: MangoBot on July 24, 2009, 06:59:19 PM

Quote from: SmAsH on July 24, 2009, 06:53:50 PM

i wouldn't try to use the $50 board... they're too different...
rather make your own. it cant be that hard.

I mean using the voltage regulator system and those things

Title: Re: Help with circuit
Post by: SmAsH on July 24, 2009, 07:03:55 PM

ahh, then yes.. the rest of the circuit is still good for anything that runs off 5v.

Title: Re: Help with circuit
Post by: MangoBot on July 25, 2009, 10:09:58 AM

if i used servos and hooked them up to the servo things for $50 dollar and only used the comparator chip would that work? and for the photoresistors could i solder them onto the underneath side of the pins? and i plan on using a 9v and 4 AA's

Title: Re: Help with circuit
Post by: Razor Concepts on July 25, 2009, 11:17:32 AM

Nope, servos require a special pulse. You could figure something out with a 555 timer chip to generate the pulse but it may just be a lot easier to use a programmable microcontroller.

Title: Re: Help with circuit
Post by: MangoBot on July 25, 2009, 11:45:57 AM

so should i instead solder the motor lead to certain pins in the motor driver

Title: Re: Help with circuit
Post by: wil.hamilton on July 25, 2009, 12:54:20 PM

After reading your 3 topics on trying to figure this out, I definitely think you should check out the BEAM "herbie" circuit.  It does exactly what you need, plus, thousands of people have built it, so, its very well documented.

here is "herbie circuit" google results:
http://www.google.com/search?rlz=1C1GGLS_enUS335US335&sourceid=chrome&ie=UTF-8&q=herbie+circuit

most of them have the herbie circuit diagram listed.  read up on it, it should be exactly what you need, if in doubt about a component, read its data sheet and see what it does.  If you read datasheets you'll learn more about the components and will be able to know which ones are good to use and which ones wont.