My first time designing a circuit and circuit board.

Jimbo30

Below are a couple pictures of the circuit I will be using for my project.· BS2p-40, MAX485 IC, two ADC0831, reed relay and some other stuff.· I must say it was a challenge and learning experience all at the same time.· The only issue I ran into was the H-bridge circuits I bought only allow 2-amps per channel so I had to order better h-bridge boards that can handle more amps.

PJAllen

It's certainly uncluttered.· Did you etch it yourself?· [noparse][[/noparse]Could've worked in an 'on' LED easily (Ooo, Aaah, LED.)]

How're you using all this then?

Jimbo30

PJAllen

I was going to try etching it at the Tech college I went to, but I figured there would be less headaches if I just used a PCB design software and have the board manufactured. As for it being uncluttered, I was nervous when designing it, lol. This board is the control system for the ROV I am building. The only thing I have left to do is the motor control. I have the motors communicating, but my H-bridge boards go into thermal overload after a few minutes of operation. I am new to robot building so it is a learning experience as I go.

Post Edited (Jimbo30) : 4/16/2010 4:23:19 AM GMT

WBA Consulting

You need to start over, it's way too clean and organized!

Very nice job, good layout. Things where they should be. Nice job making your leftover I/O pins accessible. I think that should always be done for any design.

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Andrew Williams
WBA Consulting
WBA-TH1M Sensirion SHT11 Module
Special Olympics Polar Bear Plunge, Mar 20, 2010

Jimbo30

Thanks WBAconsulting!· It really means a lot coming from a professional.· One thing I am disappointed in is overlooking·how I have the·PWM channels set up.· I have them right next to each other and what I should have done was have it so the three wire extension cables would fit nicely side by side for the H-bridge boards.· Good thing they sell one wire extensions.·

Leon

I would have mitred those right-angled corners, they don't look right. Supply and ground tracks could be wider, and you don't seem to have any decoupling capacitors.

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Leon Heller
Amateur radio callsign: G1HSM

Post Edited (Leon) : 4/16/2010 9:22:15 PM GMT

Jimbo30

Decoupling you mean filtering caps right?· My measurements didn't seem to be jumping around too much so I didn't add them.· Do you think I should have added a couple caps by the 7812 for the lights?·· Also, what is a general rule of thumb for the traces when dealing with ground and power?

Leon said...
I would have mitred those right-angled corners, they don't look right. Supply and ground tracks could be wider, and you don't seem to have any decoupling capacitors.

PJAllen

Having all that exposed copper will make the modifications a lot easier, too.

oh,... [noparse]:)[/noparse]

Leon

I meant decoupling capacitors for the MAX485 and ADC0831s. They should have one each, ideally. I'd have made the supply and ground tracks 50 mil wide.

Do you have a diode across the relay coil?

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Leon Heller
Amateur radio callsign: G1HSM

Jimbo30

The Diode I have.· I am still learning so I had no idea about decoupling using caps, but everything is operating just as tested other than my PWM channels on pin 21 and 22 of the BS2p-40.· ·
On my PWM channels, I am now stuck on trying to get the right combination of a resistor and capacitor for charge time so I can·set the speed of my motor correctly.··What seems to work well for one motor doesn't necessarily work for another motor· ·.··· I used a small 5V motor (without a load)·for testing and now that I am trying to get the 12V motor with a muffin fan on it everything is quite different due to the load I have on the motor.· I like the challenge though!· Do you have any suggestions??????

Leon said...
I meant decoupling capacitors for the MAX485 and ADC0831s. They should have one each, ideally. I'd have made the supply and ground tracks 50 mil wide.

Do you have a diode across the relay coil?