Author Topic: digilent minicon  (Read 6148 times)

0 Members and 1 Guest are viewing this topic.

Offline maverick monkTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
digilent minicon
« on: June 06, 2007, 02:48:38 PM »
im building my first robot as we speek, and i have the mechanical part down pat i think, but i am new to this kind of circutry,

http://www.digilentinc.com/Products/Detail.cfm?Prod=MINICON&Nav1=Products&Nav2=Embedded
is this a good controler for a <8inch long robot, running modified continual running servo's (3 wire futaba type) and between 2-5 sensors? i read all the information but am still horably confused, the reason i picked this ic is that i am on a REALY tight budget, and most of that was put twards a chassis that i can use in multiple robots and modifie to my needs as I go on. ( seriously considering making it water proof).

:abridged version:

will this work with 2-3 futaba 3wire servo's

will it operate with 2-5 sensors

how hard is it going to be to program, and is the programing a major language ( i know vbasic and want to learn somthing more aplicable to robotics)

what will i need to do to make a 6v 1400mah ni-mh pack work with it

is it going to be adaptable to future needs

thanks,

Offline dunk

  • Expert Roboticist
  • Supreme Robot
  • *****
  • Posts: 1,086
  • Helpful? 21
Re: digilent minicon
« Reply #1 on: June 06, 2007, 06:13:41 PM »
Quote
is this a good controler for a <8inch long robot, running modified continual running servo's (3 wire futaba type) and between 2-5 sensors?

yea, it looks pretty good value for money.
it will do everything you are asking with the right programming.
it has an onboard voltage regulator that will allow it to run off any battery between 3.5 and 9V.

without reading the website too much i get the impression you need to buy an additional programming cable as well.

so, in short, it will do what you want.

on the other hand,
if your budget is that tight and is likely to stay that way for the forseeable future you might want to learn how to use microcontroller chips directly.
the Digilent board is just a ATmega168 microcontroller along with a lot of connectors and other bits that it doesn't need to run.
you might consider just buying or building an AVR programmer which will allow you to program the ATmega168 chip along with a huge range of other AVR microcontrollers.
the AVR chips themselves will cost between $2 and $15 depending on the one you choose and the volume you buy them in.

here's some reading to get you started:
http://www.instructables.com/id/E5H5UDWB5UEUKIKV8V/?ALLSTEPS

and our own Admins tutorial that fits your design requirements without too much modification:
http://www.societyofrobots.com/step_by_step_robot.shtml
this tutorial demonstrates my point: you don't need a pre built board to get an AVR to work. Admin is using an ATmega8 rather than an ATmega168 but the principal is the same.

Quote
how hard is it going to be to program, and is the programing a major language ( i know vbasic and want to learn somthing more aplicable to robotics)

i don't think anyone on this list will argue too much if i recommend learning C.
there are boards that use versions of basic but C is the most common and flexible. (the AVR microcontrollers use C including the ATmega168 on the Digilent board you were asking about.)
as for how hard it will be to program, well as hard or as easy as you want.
there's a lot of pre written code out there. use some of that if you want an easy life. Admin has written servo controll code for the ATmega8 for his $50 bot tutorials. even with little or no C experience modifying that should be within your grasp.

dunk.
« Last Edit: June 08, 2007, 04:51:48 PM by dunk »

Offline maverick monkTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: digilent minicon
« Reply #2 on: June 08, 2007, 02:41:22 PM »
i have read both and i would do that but... my soldering skills suck, my grasp is about at small wires, and that looks too complicated for me to get without ruining everything so bad i spend more that 50$ on replacement parts. thats what i plan for a second robot, but I want my first to run to prove i can do it,

are their any tuts online for learning C? i have the time and would like to be able to code myself.

Offline Brandon121233

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 320
  • Helpful? 0
  • "Genius is %1 inspiration and %99 perspiration"
Re: digilent minicon
« Reply #3 on: June 08, 2007, 10:30:08 PM »
Also look at the Arduino board, it also uses the Atmega168, but it has a lot of tutorials on how to get started programming in the very easy to learn Arduino language ( a variant of C/C++). It is also the board I am using for Walbot right now, so I could give you help if you needed it. Heres the link: http://www.sparkfun.com/commerce/product_info.php?products_id=666
Hell, there are no rules here—we're
   trying to accomplish something.

                                                                              —Thomas Edison

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,658
  • Helpful? 169
    • Society of Robots
Re: digilent minicon
« Reply #4 on: June 09, 2007, 08:55:09 AM »
Quote
are their any tuts online for learning C? i have the time and would like to be able to code myself.

always search the forum/google before asking questions! :P
http://www.societyofrobots.com/robotforum/index.php?topic=1014.0

Offline maverick monkTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: digilent minicon
« Reply #5 on: June 09, 2007, 07:53:58 PM »
sorry for my lack of googleing ( is that a word?)

change in plans... im not using servo's anymore, im using http://www.pololu.com/products/tamiya/0061/ dual 130 can motor with between .11 and 2.2 A draw on each motor. i know i need an H bridge for this, will http://www.pololu.com/products/pololu/0215/ be enough, i cant find a amp rating on it, but it says it has a built in h bridge.l
or will i need http://www.pololu.com/products/pololu/0120/ also, if i do need that, how do i interface it with http://www.pololu.com/products/pololu/0215/ ?  this is all so confusing, any hep would be greatly apreciated, also, do the 2 motors share the same ground???

monk

Offline rgcustodio

  • Robot Overlord
  • ****
  • Posts: 217
  • Helpful? 0
  • Use "Search" and ye might find answers!
Re: digilent minicon
« Reply #6 on: June 09, 2007, 08:13:41 PM »
The Baby-O :) Yep it has a built-in H-bridge, its a Sanyo LB1836M, the spec is in the bottom of the page you mentioned :)

I also don't know the rating of the H-bridge but it should be ok for small robots. If you'll be pushing the robot hard then maybe you can get another H-bridge module.

I have those same parts in my parts bin. The Baby-O will arrive with no legs, ie the pins are not attached you will have to solder them yourself. When you solder the legs, do it like the 3rd picture here: http://www.pololu.com/products/pololu/0215/bigcompare.html the 6 pins on top is for the ISP. Believe me you wouldn't want to solder it the wrong way, that's based on experience :)

Check the schematic diagram. You will notice M1, M2, M3, and M4. You connect one motor to M1, M2. The other motor to M3, M4. You will need PWM to drive the motors. Check orangutan-lib (http://orangutan-lib.sourceforge.net/) for some samples. This is code meant to drive the Orangutans.

Goodluck!

- Rommel
The best thing one can do when it's raining is to let it rain. - H. W. Longfellow

understanding is the path to enlightenment

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,658
  • Helpful? 169
    • Society of Robots
Re: digilent minicon
« Reply #7 on: June 09, 2007, 08:20:16 PM »
Quote
or will i need http://www.pololu.com/products/pololu/0120/

I seriously dont recommend using serial to control your motors because you would no longer have serial to output sensor data to hyperterminal . . . find a dual motor driver that works by using pwm or digital output pins. Just search SoR for motor driver and you should find tons of goodies.

Offline rgcustodio

  • Robot Overlord
  • ****
  • Posts: 217
  • Helpful? 0
  • Use "Search" and ye might find answers!
Re: digilent minicon
« Reply #8 on: June 09, 2007, 08:28:38 PM »
Quote
you would no longer have serial to output sensor data to hyperterminal

Don't forget, serial can be bit-banged :) as long as you have 2 unused pins from the MCU.

-Rommel
The best thing one can do when it's raining is to let it rain. - H. W. Longfellow

understanding is the path to enlightenment

Offline maverick monkTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: digilent minicon
« Reply #9 on: June 09, 2007, 08:48:42 PM »
i guess ill just go with the baby o-tang, and ill gear it extra low so as not to stall the motor out...

does 203:1 gearing sound low enough LOL, it shouldent have to work too hard, but i doubt it will be able to get out of its own way,

is their a way to make an amperage cut off, to prevent it from colecting over howevermany amps? and like, wire it onto the positive wires.

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,658
  • Helpful? 169
    • Society of Robots
Re: digilent minicon
« Reply #10 on: June 09, 2007, 08:58:09 PM »
Quote
is their a way to make an amperage cut off, to prevent it from colecting over howevermany amps?
Hook up an ammeter to your motor and see how much current it drains. If it is too much, just lower the maximum allowed motor speed experimentally.

Offline maverick monkTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: digilent minicon
« Reply #11 on: June 09, 2007, 09:03:07 PM »
how do i do that, i understand the ammeter part, but how do i adjust it then, it seams to me it used more current when the motor stalls out, so i can

A, pray that i dont stall and pray that if i do, nothing bad happens.
or
B, find a way to limit current to, say, 1A per motor, how do i limit to 1 amp (or any other amount) although, i could find a 130can motor that only draws 1 amp max...?

this is so confusing,

edit, it says for the chip that ground pin flow out per channel is 1.0 amps, dose that mean each motor is limited to 1 amp? also, what would happeb if i stacked the mosfets ( wired them in paralel) would it give me 2A on each circut?
« Last Edit: June 09, 2007, 09:14:58 PM by maverick monk »

Offline Ro-Bot-X

  • Contest Winner
  • Supreme Robot
  • ****
  • Posts: 1,431
  • Helpful? 25
  • Store: RoBotXDesigns.ca
Re: digilent minicon
« Reply #12 on: June 10, 2007, 12:41:51 AM »
A, pray that i dont stall and pray that if i do, nothing bad happens.

If it stalls for more than a few seconds the motor coils will get hot and melt. Smoke will show up...

Quote
B, find a way to limit current to, say, 1A per motor, how do i limit to 1 amp (or any other amount) although, i could find a 130can motor that only draws 1 amp max...?

The motor will ouput a torque force. This is measured in pounds-in or kg-cm and it means it can lift that weight at 1 inch arm lenght (a wheel of 2 in diameter). If you are trying to lift a heavyer load the motor will stall. Let's say the robot pushes a wall. You have to make sure the torque is greater than the robot's weight and friction between the wheels and ground, so the wheels will spin in place.


Quote
edit, it says for the chip that ground pin flow out per channel is 1.0 amps, dose that mean each motor is limited to 1 amp? also, what would happeb if i stacked the mosfets ( wired them in paralel) would it give me 2A on each circut?

1 amp per channel means one motor can draw up to 1 amp. Most chips allow stacking, but be carefull to use heat disipators.

Power is Voltage times Current. To change Power all you have to do is modify Voltage. You do that with PWM. Don't bother much with the amp controll, just make sure the motor driver can support the maximum amperage draw. If it doesn't, change eighter the motor or the driver.
Check out the uBotino robot controller!

Offline maverick monkTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: digilent minicon
« Reply #13 on: June 10, 2007, 04:25:06 AM »
ok, how do I use the friction estemation ( conservitivly 0.8 ) to calculate the force, I dont understand the formulas, for force i have 2 lbs of force per motor, and the robot is gunna weigh less than 1 pound. so it should be absolutly fine, right? unless I use the friction of superglue on fabric. ( is their a way to use multiple friction percenteges in 1 calculation?)


thanks

edit:
nvm, its looking like im going to need a motor controler, how many analog points will http://www.pololu.com/products/pololu/0120/ take up, and how many will be left for me to use for sensors,, also, were do i find a 6pin programmer, all the ones ive seen are like, iether 10 or 12
« Last Edit: June 10, 2007, 06:17:53 AM by maverick monk »

Offline rgcustodio

  • Robot Overlord
  • ****
  • Posts: 217
  • Helpful? 0
  • Use "Search" and ye might find answers!
Re: digilent minicon
« Reply #14 on: June 10, 2007, 11:15:28 AM »
Quote
nvm, its looking like im going to need a motor controler, how many analog points will http://www.pololu.com/products/pololu/0120/ take up, and how many will be left for me to use for sensors,, also, were do i find a 6pin programmer, all the ones ive seen are like, iether 10 or 12


You don't need the input to the module be be analog. Read the data sheet here:
http://www.pololu.com/products/pololu/0120/smc05a_guide.pdf
it contains several wiring examples and programming basics. It should be able to help you out. There is no replacement to reading the actual data sheets, make it a habit.

If you can afford it, Pololu has a 6-pin USB-capable ISP programmer. Check the "What's new" page. Most likely you'll need avrdude or ponyprog. Search the forums, its been discussed in the past and there are still open threads for that topic.

- Rommel
The best thing one can do when it's raining is to let it rain. - H. W. Longfellow

understanding is the path to enlightenment

Offline maverick monkTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: digilent minicon
« Reply #15 on: June 10, 2007, 11:45:52 AM »
im reading them, but, im not getting them, but i understand this much, i can use that H-bridge and still have sensor imput? how many sensors? what do all of these things ( pd1, pc1, pb1) meen, whats the difference, i looked in the manual things, but i just dont get it

sry, i know i am anoying, but, this is confusing, i thaught the mechanics and programing would be the hard part.
« Last Edit: June 10, 2007, 11:48:53 AM by maverick monk »

Offline rgcustodio

  • Robot Overlord
  • ****
  • Posts: 217
  • Helpful? 0
  • Use "Search" and ye might find answers!
Re: digilent minicon
« Reply #16 on: June 10, 2007, 12:08:56 PM »
Reading data sheets can be a daunting task at first but you'll get the hang of it.

Quote
i can use that H-bridge and still have sensor imput
Of course! On page 4 of the PDF I gave earlier, you will see that only 2 pins from the MCU/MCU board is used. You select which pins to use, as long as you can put out a serial signal on those pins.

Quote
how many sensors?
The ATmega48/88/168 family has 8 10-bit ADCs which you can use for sensors.

Quote
what do all of these things ( pd1, pc1, pb1) meen
If you will read the data sheet of the ATmega48/88/168 you will see these are ports/pins. They map to an actual pin on the chip. You connect your devices to these ports/pins.

Goodluck!

- Rommel
The best thing one can do when it's raining is to let it rain. - H. W. Longfellow

understanding is the path to enlightenment

Offline maverick monkTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: digilent minicon
« Reply #17 on: June 10, 2007, 12:25:47 PM »
thanks, i think i finaly get it  :o

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,658
  • Helpful? 169
    • Society of Robots
Re: digilent minicon
« Reply #18 on: June 10, 2007, 12:28:55 PM »
Quote
ok, how do I use the friction estemation ( conservitivly 0.8 ) to calculate the force, I dont understand the formulas

which part dont you understand?

try the excel sheet, it does all the math for you:
http://www.societyofrobots.com/downloads/RMF_calculator.xls
(fill in the yellow boxes, and the answers are in red)

Quote
for force i have 2 lbs of force per motor, and the robot is gunna weigh less than 1 pound. so it should be absolutly fine, right?

not really, because motors apply torque, not a force.

Offline maverick monkTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: digilent minicon
« Reply #19 on: June 11, 2007, 07:59:42 PM »
ok, question time again, I am not willing to spend $27 on a programmer for a $25 microcontroler so I took a look at

http://www.pololu.com/products/pololu/0126/ I like this better than a plug in wire because i can have a serial port in the back of my bot and I wont have to disassemble anything to programm it. and it costs the same as a plug in controler.

now, the million dollar question, how do I attach it to the baby orangutang
the thing has no manual or shematic, but it says this V i cant figure out what it means so far as to what wire goes from what pin to what pin, please help

"This adapter distinguishes itself from most competing units through its five drivers and three receivers, which give you access to all eight signal lines on a DB9 connector (the ninth pin is ground). This means that in addition to standard serial communication, your project can also use all of the handshaking lines and status lines. Even if you do not use them for their intended purposes, you might find it convenient to be able to reset your processor using one of the extra lines. A connection detection line gives your project additional options for responding to a physical connection to a serial port. All of this connectivity comes in a compact package that is less than twice the size of the DB9 connector alone.

The first nine pins on the deluxe serial adapter correspond to the same nine pins on a COM port DB9 connector. The additional pins are the logic supply voltage, the serial connection detection pin, and an inverted version of the transmit line (which can be useful if, for instance, you have a positive-edge triggered interrupt that you want to fire in response to the beginning of the start bit). The TX line and RX lines are labeled from the computer's perspective, so the TX pin has data transmitted by the computer that should be connected to your project's receive input. "


edit: teaser pics



« Last Edit: June 11, 2007, 08:03:57 PM by maverick monk »

Offline rgcustodio

  • Robot Overlord
  • ****
  • Posts: 217
  • Helpful? 0
  • Use "Search" and ye might find answers!
Re: digilent minicon
« Reply #20 on: June 11, 2007, 11:00:48 PM »
First, what do you want to achieve? If you only want a serial connection to your robot connecting the MCUs RX and TX to the TX and RX (yep you cross them) of the serial board. You can then connect a terminal emulator to the serial port.

If you want to use this serial board as a "programmer" (so that you can download your programs from your PC to your robot) it might work since the signals are already TTL level but you will still need additional hardware to achieve that. Not assured since I haven't tried this myself.

- Rommel
« Last Edit: June 11, 2007, 11:51:30 PM by rgcustodio »
The best thing one can do when it's raining is to let it rain. - H. W. Longfellow

understanding is the path to enlightenment

Offline JonHylands

  • Expert Roboticist
  • Supreme Robot
  • *****
  • Posts: 562
  • Helpful? 3
  • Robot Builder/ Software Developer
Re: digilent minicon
« Reply #21 on: June 12, 2007, 06:51:14 AM »
You realize you can't actually program a Baby Orangutang using a serial converter, right?

The reason we spend $27 on a programmer is it is a one-time purchase, and you can program an unlimited supply of micro-controllers with it.

- Jon

Offline maverick monkTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: digilent minicon
« Reply #22 on: June 12, 2007, 07:15:01 AM »
i cant program it with a serial converter? oh, well then, that kinda sux.

this orangutang is confusing me bad, i might just go with a didgilente mini con, with a 2 A h-bridge and a jtag3 to serial programmer. now, are they going to work together?? the baby Orang was way to confusing, this seems to be more modular..

also, i am right in thinking that the 2 pin conectors are for sensors? and the ground goes to the main ground?



https://www.digilentinc.com/Products/Detail.cfm?Prod=PMOD-OD1&Nav1=Products&Nav2=Peripheral
https://www.digilentinc.com/Products/Detail.cfm?Prod=MINICON&Nav1=Products&Nav2=Embedded

Offline Admin

  • Administrator
  • Supreme Robot
  • *****
  • Posts: 11,658
  • Helpful? 169
    • Society of Robots
Re: digilent minicon
« Reply #23 on: June 12, 2007, 07:20:33 AM »
Quote
this orangutang is confusing me bad
I dont use Pololu products because they dont offer any support, source, or examples for their own poorly documented products. (admin, being Mr Negativity :P)

Offline JonHylands

  • Expert Roboticist
  • Supreme Robot
  • *****
  • Posts: 562
  • Helpful? 3
  • Robot Builder/ Software Developer
Re: digilent minicon
« Reply #24 on: June 12, 2007, 07:31:33 AM »
this orangutang is confusing me bad, i might just go with a didgilente mini con, with a 2 A h-bridge and a jtag3 to serial programmer. now, are they going to work together?? the baby Orang was way to confusing, this seems to be more modular..

also, i am right in thinking that the 2 pin conectors are for sensors? and the ground goes to the main ground?

https://www.digilentinc.com/Products/Detail.cfm?Prod=PMOD-OD1&Nav1=Products&Nav2=Peripheral
https://www.digilentinc.com/Products/Detail.cfm?Prod=MINICON&Nav1=Products&Nav2=Embedded

The minicon looks great if you're going to use their system, with their modules. The programmer you mention is more expensive than the general purpose one from Digikey, and will only work with the minicon hardware.

The two-pin headers on the minicon board all look like jumpers. You don't get access to the actual I/O on the AVR - it looks to me like you have to plug in these serial modules using the six-pin connectors to do anything.

Very nice for beginners, but very limiting and extremely expensive in the long run.

- Jon

Offline maverick monkTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: digilent minicon
« Reply #25 on: June 12, 2007, 07:50:06 AM »
*hears the beginning to "money" in his head* darn, i was hoping it would come out cheaper. any suggestions on a 3A dual motor H bridge and a nice simple cheap avr controler? idiot proof if possible. I see so many on this sight, but i honestly havent got a clue what to look for

Offline JonHylands

  • Expert Roboticist
  • Supreme Robot
  • *****
  • Posts: 562
  • Helpful? 3
  • Robot Builder/ Software Developer
Re: digilent minicon
« Reply #26 on: June 12, 2007, 08:26:34 AM »
I would just buy one of the DIP ATmega chips ($5), the protoboard stuff mentioned in the tutorial, and the Digikey programmer.

For an h-bridge, if you need 2 channels at 3 amps, it isn't going to be cheap...

http://www.dimensionengineering.com/Sabertooth2X5.htm

If you can get away with 2.5 amps, you can use an L298 h-bridge chip, and drive it directly from the PWM outputs of the AVR.

You can either use raw chips and not spend much, or you can buy modular components that work well together, but spend a lot of money.

There is very little middle ground...

- Jon

Offline maverick monkTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: digilent minicon
« Reply #27 on: June 12, 2007, 08:35:44 AM »
ok, I guess Ill try making my own board. how do I utilize the power chip? like how do I attach it to the board and wire it in to the 2 motors, tha battery and the ic?

anyone have a simple schimatic for making your own dual h bridge?
« Last Edit: June 13, 2007, 10:35:00 AM by maverick monk »

Offline maverick monkTopic starter

  • Robot Overlord
  • ****
  • Posts: 204
  • Helpful? 0
Re: digilent minicon
« Reply #28 on: June 13, 2007, 11:22:44 AM »
bump I searched google but all the plans I found were iether WAY over done, or too half assed to understand, can somone help with a dual h bridge schematic that I can actualy build? or a cheap kit with at lease 2.5A per channel?

Offline JonHylands

  • Expert Roboticist
  • Supreme Robot
  • *****
  • Posts: 562
  • Helpful? 3
  • Robot Builder/ Software Developer
Re: digilent minicon
« Reply #29 on: June 13, 2007, 11:37:17 AM »

 


Get Your Ad Here