RS-232 Robot Controller

Lynxmotion
1

Hi all,

soon I will be getting a Basic Atom Pro, and I want to design a board for it that fits my specifications. which are:

  • Very tiny form factor

  • On-board FTDI Serial to USB microcontroller (SMT SSOP)

  • On-board 5v Regulator

  • Extra space left over for expansion

The board will be made using the Toner-Transfer method (I haven’t done it yet but I found all sorts of helpful video’s on youtube on how to do this.
I am going to need to buy a magnification device of some sort for soldering the SMT FTDI chip to the board. I saw some video’s on how to solder SMT devices and it looks quite easy. just spread some flux along the pins and the solder just sticks on, Right?

Right now the board meets my specifications and may I say it is VERY tiny. of course I could get the same dimensions using a serial port connector instead of USB, but this board is for tiny robots so I would like something more portable. I have looked over the data sheet for the FTDI FT232RL but I can’t be too careful. I think I may have not understood something and connected something wrong.

Chip here:
parallax.com/Store/Component … fault.aspx

Datasheet here:
ftdichip.com/Documents/DataS … R_V202.pdf

Also, regarding the regulator, I have never used a regulator before and I’m not sure if I connected it right. Can someone confirm that I did please?

http://www.majhost.com/gallery/DarthToa/Robots/capture1.png

2

Pretty cool.

The AX0, AX1, AX2, AX3 are specific to the Atom not the Pro. Yes I know it’s that way on my current Bot Board II.

The large area is normally connected to ground and then called a ground plane.

No better way to learn then to just jump in. Nice work.

3

Yeah, I did realize that. I still have to fix it. Atom Pro has 8 A/D pins right?

Thanks!

EDIT: ROFL nm. I just went over to look as the pinouts. The other four pins are D/A. I really thought there were 8 A/D pins.

4

Good work. To connect to a power or ground plane, right click on the pad and select from the popup menu. Details are in the quick start guide.

5

The Atom Pro has 8 analog inputs.

P0, 1, 2, 3, 16, 17, 18, 19.

6

Like this?
http://www.majhost.com/gallery/DarthToa/Robots/capture2.png

I was wandering how you do that. Thanks SN96. :slight_smile:

@ RobotDude: I guess I really can’t think right now. I just looked at it and I thought it said Digital to Analog…

BTW I measured the board, it’s 2.5"L x 1.75"W. :confused:

7

Bingo! thats it!

8

Hello,

I have a few updates on the project.

  • I will now be using RS232 instead of USB because it seems to complicated for me so I don’t thing I’m ready yet.

  • The board is now a 2 layer board because I am very limited to what I can do with a single layer board. I have also decided to have the boards made for me.

Here is a picture of the NEW and improved board:

http://www.majhost.com/gallery/DarthToa/Robots/capture3.png

9

Nice work on the board!

You might consider Basic Micro “Nano” chips. I believe the do the same thing (well, you’d have to add level conversion), but they’re in a “skinny” package.

Another alternative would be buy your own PICs, and the MBasic compiler.

Alan KM6VV

10

wowy I don’t see any capacitors on the power going into the regulator or out of it. if you check the data sheet for the regulator there will normally be guidelines on how much capacitance is necessary to keep the regulator from oscillating. nice work so far though. :wink:

11

I noticed the same thing. He has it direct connected to the regulator. You want caps for over voltage protection as well. Like Eddie said, I would check the data sheet for some examples.

Good work on the board. 8)

12

Nice work!

I know there are many here who are much better with the designing a circuit than I am, but I wonder if you need the seperate jumpers for the grounds of the two power supplies?

Also if it were me, I would probably like the ability to have some pins that are VS and others VL. Maybe you could use the second jumper space to have seperate jumpers for the left side versus the right side? But then again maybe for your application you won’t need this!

again great work!

Kurt

P.S. - If you are wanting something small and still be an Atom Pro (only 8 IO pins), maybe try the Pro 1m basicmicro.com/downloads/datasheets/B0221.pdf. It would be great to have a real small board to use to extend the number of IOs we have or to maybe offload some processing to…

13

What would really be cool is if the atom pro came in an self contained SOIC28 or a PLCC28 package. That would make it really small.

14

Thanks!

I have considered that. But they are the standard Atom processor, and this board I am making is because I want to use the Pro. :wink:

Thank you for pointing that out. I did say before that I had never used a regulator and wasn’t sure how to connect it. :slight_smile:

Actually I have the data sheet open right now and I don’t see anything about connecting regulators. :wink:

Thanks Kurt, those are some good suggestions. I have actually thought about adding seperate jumpers for all 20 pins. I haven’t tried it but I don’t think that will fit. :wink: So I just added a jumper at the front of the board. Besides, I usually just power 5v to my servo’s anyway.

I do like that Pro 1m controller. Looks very handy and would really save allot of room. I’ll have to look into that…

That’s a pretty small package to fit so many things in! :laughing:

Thanks for the comments everyone!! :slight_smile:

Brandon C.

15

wowy, if you would like to, put up your schematic and we’ll take a look at it and make suggestions on where to add caps and looks for any other gotchas.

16

As a general rule it is good to make a working prototype prior to spending time and $$$ on having boards made that may need more development.

17

Just what I was going to suggest!

And again I must comment that Basic Micro has the smaller Nano chips, which are a PIC with the same code, but you add the level conversion and xtal.

Alan KM6VV

18

I have a question:

Does the BasicATOM Pro have a built-in regulator or something? I was just reading through the pinouts and there was an image with “A B C D” on it, pointing towards certain parts of the Microcontroller, and it says the “D” is a Power regulator.

Alan, the Nano chip is nice but I don’t think it’s as fast as the ATOM pro.

19

I was sure I just answered this. Another thread?

Yes, the Atom and Atom Pro have a built-in regulator (MC5207-05, I know I did), a transistor and a transistor array for level conversion, and oh yeah, a serial EEPROM on the 'pro.

Alan KM6VV

20

I think it was another thread. :wink:

Well in that case I should just remove the regulator from my board to save even more space?