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Author Topic: voltage regulator for the 50$ robot.  (Read 535 times)

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Offline donisTopic starter

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voltage regulator for the 50$ robot.
« on: November 25, 2010, 01:47:00 PM »
Hi, i'm new to robotics and one of the first things i started with is the 50$ robot. it looks like i did fine with the circuit though i have one problem, the 5v linear regulator doesn't emit any power. could it be that a) i got wrong regulator b)it has too high amperage c) it just isn't working by default? i got pos v-reg 5v 1.5A ua7805 if you prefer also the shop where i got my parts was out of ATMEGA8-16pu's so i went with ATMEGA88PA-PU, it still should work right?  
« Last Edit: November 25, 2010, 01:57:00 PM by donis »

Offline VegaObscura

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Re: voltage regulator for the 50$ robot.
« Reply #1 on: November 25, 2010, 02:34:01 PM »
also the shop where i got my parts was out of ATMEGA8-16pu's so i went with ATMEGA88PA-PU, it still should work right?  
Not if you're using the serial dongle programmer.  The dongle has a limited selection of controllers that it can program and the atmega88 isn't one of them.  I made the same mistake, figuring since it was almost the same controller and even had the same pinouts, it would work but it doesnt.  When I took out the atmega88 and put in an atmega8 everything worked fine.

From sparkfun.com:
Supported Devices: The currently supported devices by PonyProg software, which can be programmed by AVR-PG1B are:
AT90S1200, AT90S2313, AT90S2323, AT90S2343, AT90S4414, AT90S4434, AT90S8515, AT90S8535, AT90S2323, AT90S2343, AT90S2333, AT90S4433, AT90S4434, AT90S8535, AT90S8534, ATmega103, ATmega161, ATmega163, ATmega323, ATmega128, ATmega8, ATmega16, ATmega64, ATtiny12, ATtiny15

If you're using the more expensive AVR ISP2 Programmer, you can use just about any avr chip out there.

As for your 5V regulator issue; use a multimeter and make sure you have at least 6V between the unregulated and gnd pins of the regulator.  If you have 6V or more there and don't have 5V between regulated and gnd pins, you have a bad regulator.

Offline donisTopic starter

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Re: voltage regulator for the 50$ robot.
« Reply #2 on: November 25, 2010, 02:48:10 PM »
also the shop where i got my parts was out of ATMEGA8-16pu's so i went with ATMEGA88PA-PU, it still should work right?  
Not if you're using the serial dongle programmer.  The dongle has a limited selection of controllers that it can program and the atmega88 isn't one of them.  I made the same mistake, figuring since it was almost the same controller and even had the same pinouts, it would work but it doesnt.  When I took out the atmega88 and put in an atmega8 everything worked fine.

From sparkfun.com:
Supported Devices: The currently supported devices by PonyProg software, which can be programmed by AVR-PG1B are:
AT90S1200, AT90S2313, AT90S2323, AT90S2343, AT90S4414, AT90S4434, AT90S8515, AT90S8535, AT90S2323, AT90S2343, AT90S2333, AT90S4433, AT90S4434, AT90S8535, AT90S8534, ATmega103, ATmega161, ATmega163, ATmega323, ATmega128, ATmega8, ATmega16, ATmega64, ATtiny12, ATtiny15

If you're using the more expensive AVR ISP2 Programmer, you can use just about any avr chip out there.

As for your 5V regulator issue; use a multimeter and make sure you have at least 6V between the unregulated and gnd pins of the regulator.  If you have 6V or more there and don't have 5V between regulated and gnd pins, you have a bad regulator.

thanks for the info. i'll be useing avt prog2 programmer, as i bought it at the same time as the chip i think it should do the job.

as to the regulator it is working fine, i was just too dumb to see the mistake. though i'll be able to use a multimeter tomorow, still have to check if the regulated power is correct.

Offline Soeren

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Re: voltage regulator for the 50$ robot.
« Reply #3 on: November 25, 2010, 03:53:13 PM »
Hi,

As for your 5V regulator issue; use a multimeter and make sure you have at least 6V between the unregulated and gnd pins of the regulator.  If you have 6V or more there and don't have 5V between regulated and gnd pins, you have a bad regulator.
6V isn't quite enough with 7805's. At least around 8V in is needed for proper regulation - An LDO regulator OTOH can work with a 0.5V to 1.0V drop.
Regards,
Søren

A rather fast and fairly heavy robot with quite large wheels needs what? A lot of power?
Please remember...
Engineering is based on numbers - not adjectives

 


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