Society of Robots - Robot Forum
Electronics => Electronics => Topic started by: yash25 on July 03, 2009, 04:22:01 AM
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Hi! I'm an amateur robotics enthusiast, and I've built only basic BEAM bots till date. Now i wanted to build this kind of a microbot http://www.instructables.com/id/Building-Small-Robots-Making-One-Cubic-Inch-Micro/ (http://www.instructables.com/id/Building-Small-Robots-Making-One-Cubic-Inch-Micro/)
Here, the author is using a picaxe conntroller.Now, I cant find a picaxe microcontroller in my city, so can i get help regarding any other microcontroller I can use for this, which is of the same size but can be programmed in C( say AVR)?
Thanks and best regards to all!
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yeap, you could check out the attiny13, attiny2313 or atmega8/168/328... (from smallest to largest)...
these will require a small h-bridge ic but it will not take up much space.
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Thank you so much smash!
and do i program these with the winAVR i've got at home?
also, do i etch a board for such a circuit or do i do simple wiring?
thanks again!
cheers!
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You program with AVRStudio.
With the circuit board do what you can; if you have access to producing PCB's then go with that, if not go with wiring. Basically go for the smallest and cleanest method which i think is PCB.
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thanks miles..btw, does AVR studio run with windows? or is it linux based like AVRdude and others?
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nope, its for us windows users too ;D
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I use it on windows XP and thats all i've ever used. I would recommend downloading the latest version 4.16 and i think it has an upgrade for that version as well.
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Thanks folks..i know my doubts are basic but im reely new to this..so thanks for bearing with me! okay, so while i was typing all of this, i got one more query. Out of the chips that smash suggested, which one would be most recommended? Why?
So, my basic query is that what are the properties which make u choose a particular controller and reject the others? also, if im building a microbot, which property would i search for in a chip? and so on... i hope u guys get my point..
thanks again!
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i would try use a pcb as it can reduce the size of the circuit board by half if you design it well enogh
good lick with the circuit board
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well, the first chip (tiny13) is the smallest but has the least amount of memory and I/O...
the atmega8/168/328 is the most popular avr chip as it has 20 I/O ports..
but i would think the tiny2313 would fit the best here because it has like 5 I/O and its fairly small...
generally you choose the board because of I/O numbers, speed, size and memory...
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I saw this done before with the atmega 8 and then they communicated with ir it was a whole swamof these little things... but they had little micro servos taht were used off of a camera and they only required like one AA batterie and that was in the middle lining up with the bot going straight and then there were to small circuit on both side each with a motor out put that ran straight to the ic chip and the back had the infrared stuff and last but not least in the front they had the atmega... the cool thing about these is they only cost about 15$ or less to make and that they can fit under doors
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can etching be done at home? if so, can anybody suggest me any resources or links where i can learn this process?
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http://www.wisegeek.com/what-is-etching.htm (http://www.wisegeek.com/what-is-etching.htm)
read that....
I believe that you may not want to use metal for this is if that is why u asked its to light and really to small for me to do it...
and it your not intending to do it for this you should have started a new post :P
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yaa..but how do i do ithe etching at home?
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Okay..now i have my Attiny 2313...and im planning to do the schematics now...do i make a standard programming board first or do i directly make the final bot circuit?
also how do i program the chip. using parallel port(dunno i think it's called ISP right?) or serial?
what frequency crystal do i use?
also, if there is any standard schematic with anyone can u please give me the file or the link?
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??? y didnt u say you needed to know this much when you first posted you acted as if you had everything down pat.... and new this part... my best advice is to get the 50$ robot built because it will give you all the libraries you need for basic robotics programming
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Well, i did give a better introduction of myself in my other post in the list (the one about the Butler Bot)...well yes, my knowledge is very weak about microcontroller robots..yes, and im trying to learn..and yes, im trying to learn the 50$ bot ...
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theres nothing better than learning by doing.... when you say beam robotics that could be as simple as adding one batery to a couple of motors and strapping it to a base to were it has ability to move....
for more advice on this read my signature because the second part says basically if you try something to hard like i once did youll end up just having to go back and do the things you skiped.... trust me i learned this the hard way.... you may be an engineer student but learning by yourself and being taught are two different things... ive read the same books over and over again to make sure i dont miss a single thing....
good luck
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jamort is right, do not attempt something over your head...
to make the schematic you will need to look up the datasheet for the part, google "attiny2313 datasheet".
find out which pins do what, for a microbot you wont really need any analogue ports, only digital.
if some ports can handle pwm, they should be used for the servos and the other ports for the sensor(s).
etching can be done at home, there are tonnes of tutorials out there, google it.
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yes..i guess jamort is right..I should attempt the 50$ bot first! well, i can't seem to find the atmega8 here in my city, can u suggest any other chips? Also, can i possibly make the microbot using tips from the 50$bot tutorial (cuz i could find someone who sells tiny2313) maybe compare the datasheets(of atmega8 and tiny2313) and connect the pins accordingly(with the addition of a motor driver of course)..maybe i can burn the same programs of a wireless bot or a photovore suggested in the 50$tutorial?
well, these are just my ideas..i'm sure you'll can suggest something better for me!
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Its going to be a pain finding motor drivers small enouhgh for a micro robot my best suggestion is micro servos.... the only differnece between the atmega 8 and attinys is that they have diffferent pins same code just different ports with in the code
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why not an L293D? well i've worked a lot of times with them some years ago, so i should get the connections fine..also these are the motors im using http://www.solarbotics.com/products/gm15/ (http://www.solarbotics.com/products/gm15/)
but should i go ahead with the microbot then? i'll build it using the 50$ bot as my template and i'll program in the same way, making the same connections but on a smaller scale, and with the tiny2313, instaed of the mega8 ..what do you suggest? should i go ahead with this?
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the l293d will work fine but i would recommend the micro servos as well because they are plug in and play with microcontrollers...
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any good places where i can buy microservos from? and will i have to hack into them too???
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hey james..can u suggest any good model of microservos you know of???
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not really, just look for some with the things you require, ie. speed, torque, weight (most are 9g), size etc...
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acutally torque wont be a problem here..i assume i'll have to go for the smallest size...is it ok if i post my schematic here later???
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yea, that sounds fine.
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If you're still looking for a controller that is small, check this one out: http://bittybot.com/index.php?pageId=MEGAbitty (http://bittybot.com/index.php?pageId=MEGAbitty)
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thanks galannthegreat! i guess im using the tiny 2313...already bought one today morning!i hope it's ok if i put up my schematics and CAD design for approval for you'll to approve for me!
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yeap, post it and ill have a run through it.
remember to post screen shots of it too, for people who cant be bothered to open up cad or eagle.
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Hey james, im posting the schematic of the circuit as u advised me..its an EAGLE file ,( but i'll be posting the handdrawn schematic in sometime)..can u check the schematic for me please?
in the schematic, the capacitor symbols to the extreme right are photoresistors . Also, the pin headers on the top and bottom are for attaching to the lower part of the circuit. I have used the pins of the pin header as VCC and GND and also as connections to the motors.
I am also posting the CAD in sometime. It's going to be a three layered bot , the first layer has the circuit, 2nd one has the cells and regulator and motordriver IC and on the third layer i will be mounting the motors!
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okay i'd made a mistake in my connections..i'd connected only one of the motordriver inputs to the chip...the other two connections are from pin 6 and 7 of the chip to the pins 1 and 2 of the header! Here's the file again, modified this time!
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smash..i know u'd suggested microservos..but they're just too big..so im using pagers with anL293D...do check the circuit posted above...it doesnt contain the motor driver..but the basic circuit of the tiny 2313 is there. could u look it up please?
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Nice! I hope your project goes well!
P.S. Keep us posted on progress, it sounds like something very cool. ;D
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Hey Thanks a lot! That's made my day(well, on my side of the world, the day's just started!)! It's going to be difficult since it's my first microcontroller based bot and it's tiny..but my CAD's gone perfect and I think my schematic is somewhat right!
Can u please check it for me ? because then i can go down in the city and buy all the components!
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Now... If you need some motor controllers/driver, the MEGABitty comes built-in with drivers.
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yes i've heard of MEGAbitty ,but i think it would be more fun designing the whole thing myself so...and back in my college, if i ever submit this as an entry to any project disply, they'll disqualify,because im using a readymade board.
that's why the schematic and all...did u check out my ckt? are all the connections right???
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I'm pasting the EAGLE FILE here again!
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Can you please export the schematic as a png and attach it? This way I can look at it easier. Thanks.
P.S. Perhaps it will help to take a look at my schematic for a dual motor controller using tiny2313 here:
http://www.societyofrobots.com/robotforum/index.php?topic=8052.msg63205#msg63205 (http://www.societyofrobots.com/robotforum/index.php?topic=8052.msg63205#msg63205)
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Never mind, I have looke dat your schematic and I find it incomplete. I know you want to build several boards connected together but you can draw the schematics one near the other and make the boards on the same pcb like 2 square cells and cut them out after they are etched.
But I need to know what kind of robot you want to build, a sumo, line follower, photofobe, mars lander... so I know what kind of sensors you can use. Motor connections are simple, that's not a problem.
I have built small robot boards with perfboard and wires and housed them in a 4x4 studs Lego brick. It could read 2 Lego sensors and control 2 Lego motors and 2 servos, plus it had dual IR proximity sensor integrated. So, it's all possible. Here's a link to it:
http://www.societyofrobots.com/robotforum/index.php?topic=7546.msg58063#msg58063 (http://www.societyofrobots.com/robotforum/index.php?topic=7546.msg58063#msg58063)
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hi! i've never actually dealt with sch files a lot ..so i reely dunno how to export them as png and attach them , im trying though...can u help me out with this? :-[
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oh ok sorry...please ignore the last post about my confusion with the png.. :D..well actually..im building a photovore...in fact , basically, im only building the 50$bot but on the tiny scale! my bot dimensions are 1inch * 1 inch*1.5 inch...
okay..see, i know what u say is perfect...but my boards are going to be one on top of the other..so im giving the VCC and GND and those outputs of the chip that are going to the motors, to the pin headers!
also, it would be practically impossible to cut the boards after they're etched..because i don't have such good machinery available to me! also this being my first microcontroller project , im a bit wary about losing out due to poor cutting of the PCBs ...
so im giving my VCC ,GND, and motor pins to the strips(which will also act as stilts for the bot) i'll take these connections out with wires and connect them wherever required..
i hope i hav'nt messed up bigtime! have i???
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well, i forgot to tell you one more important reason of why the whole circuit is not present on the schematic is dat i am not going to acutally mount the remaining componants but i'm going to freeform them! so, making a schematic of it did'nt actually appeal to me...it would've been a waste anyway...i know it's hard for u to picturize the circuit with wires going nowhere and ending up in pin headers!
apart from these incomplete cannections..is there anything missing?