servo controllers
Badger
Posts: 184
Hey
does anyone know how to teach an old dog who dont know how to read schematic very well but learning. tell me how to build a dc motor control that uses an external power supply with reverse with speed control (i will wright the software is necessary) or will trade an armite board from coridium corp. for a controller that will do this. I want to run it off the propeller board i have because it has the sd slot built in so i can store data there for the program to use if necessary .
Badger
does anyone know how to teach an old dog who dont know how to read schematic very well but learning. tell me how to build a dc motor control that uses an external power supply with reverse with speed control (i will wright the software is necessary) or will trade an armite board from coridium corp. for a controller that will do this. I want to run it off the propeller board i have because it has the sd slot built in so i can store data there for the program to use if necessary .
Badger
Comments
An example is the PPDB with a L293D driving 2 small motors. Or the 2 tb6612 driving 4 motors. It should handle up to 8 motors but I haven't tried more than 4. Both these drivers take a separate power supply for the motor.
With the L293D, pins 1,2,7,9,10,15 connect to prop pins, 8 to the motor power, 16 to +5V, 4,5,12,13 to ground.
If you need more power than L293D then pololu have some 20A motor drivers that it should be able to drive though I haven't tried it.
PS I have only recently added the PCF8574 support so that may have bugs.
PS this is a DC motor speed controller not a servo controller
Post Edited (Timmoore) : 10/2/2008 1:37:23 AM GMT
thanks for the code due to the fact i am really new to all of this. I know dos basic, quickbasic, visual basic, a tiny bit of c++, and was a long time ago fairly well versed in borlan pascal. I have a list of stuff i stuff coming in from TI here is a list of the chip numbers.
ONET4291VARGPTG4 Green 5 5 item shipped on 09/30/2008
SN65LBC184D Pb-Free 5 5 item shipped on 09/30/2008
TMP100NA/250 Green 5 5 item shipped on 09/30/2008
TMS320F2809GGMA 1 1 item shipped on 09/30/2008
TPS54612QPWPRQ1 Pb-Free 5 5 item shipped on 09/30/2008
TRF7961RHBR Green 5 5 item shipped on 09/30/2008
TSB83AA23ZAY Green 5 5 item shipped on 09/30/2008
TSC2300IPAG Pb-Free 5 5 item shipped on 09/30/2008
and the amounts i ordered. if you can let me know if one of these will work. Some them are temp censors and others or fiber stuff but i cant remember which ones are power chips.
could you let me know.
I am just now taking electronics courses so i am learning .
so i am trying .
Badger
I will look into your suggestion write away. it will take a little time to find what i am looking for due to that i dont know what i am looking for LOL. I will find it. Then i will as you said ask your help .. I am trying to build a robot and need to build the mobility base. I also need to try and build a gearing system due to these motors at 1 am and 3.5 volts turn 1800 rpm with out load and 5800 under load. i dont think the sonar censor will react that fast LOL . i will do some research
Badger
I have 2 remote control receivers here i think one is still intact can that help me. it has some other stuff on it. the steering servo has somethings on it that i dont know what it is. it has a positive and neg. power leads and a 4 wire control wire on it as well. It has 3 prongs in the spindle gear box that seem to act like a switch to let the controller know the position of the servo.
i hope you can make heads or tales the above .
Badger
You are building a robot, you have some motors - the specs of the motors say 3.5V 1A. How big/heavy is the robot? how much does it need to carry and how fast? Wheels or tracks?
If this is your first time, I would suggest getting a motor driver chip rather than building a driver from MOSFETs. Unfortuntely I dont know of a motor driver that runs at 3V. I had the same problem recently - I was hacking a toy that used 3V motors, the easest way was to change the motors to 6V motors the same size, then one of the cheap standard motor driver chips would work (I used the L293D). I ended up running the 'toy' of a 7.2V nicad, the motors directly off the battery and the same battery into the power in of a propeller board. The new motors were only $2 each which was much cheaper/quicker than finding/designing a motor controller that would work at 3V.
If you want a TI motor driver then the SN754410NE works but only down to 4.5V. Its basically the same as a L293D and available for < $2.
In terms of your steering servo, I would guess it has some form of motor driver on it, probably uses a DC motor, the 4 lines control the motor. The +ve/-ve provide power, the other 3 pins are probably a limit detector, 1 pin will be connected to 1 of the other pins at either end of the steering i.e. when the steering is full 1 way, 2 of the pins connect together, when full the other way, 1 of the previous pins connect to the 3rd pin. Are the any numbers on the steering servo?
These are the only motor i could find at rat shack that had a mettle gear on them. I dont yet have any gear boxes to put them in. that is the reason i said i would trade my armlite board for something like that. the robot does not need to be fast and is not going to be more than 5 or 6 pounds. I dont think i am going to push the amps out that high i dont think i need it. Plus i am using a parallax sonar censor and it does not react fast enough to be moving that quick. I also would love to be able to build 2 ir censors for side to side object detection but that is pretty far into the future. Money is not available here due to having to put my oldest in a special private school. He has a condition called aspergers syndrome it is a form of autism he is looks and acts normal but when it comes to reading it is not there. He is real good in math and as long as we have someone read what ever he needs to do for him he does a's and b's but that is expensive. my youngest goes there on a financial hardship clause for the second child so we lucked out on that.
anyway i want to put it on tracks and so be it I only have one track my kids lost the other a few months ago so i am looking for something there so. I will find it mean while just want to be prepared for when it all comes together. I am going to build it out of balsa wood and would dowl rods. I dont have a steel mill or lath so i have to punt cant even find a good erector set i have one but it does not have enough part and such. I have about 5000 legos LOL ..
any ideas on how to build a gearing system i can rake up some gears from some old printers and such and that frame i will have to build out of aluminum .
Badger
ps it is late and rainy here. I have had to take a bunch of pain meds so my writing is a little off. if you have question or dont understand what i have written in any of my post please ask ok
I just put a couple of small robots together recently for some school children. One was a small trackbot, it is just over 2lbs. What I did was to get a Tamiya track kit http://www.superdroidrobots.com/shop/item.asp?itemid=409 - you can get them cheaper looking around, and a tamiya twin gearbox (http://www.superdroidrobots.com/shop/item.asp?itemid=408). Fastened them to a small piece of wood 6x2.5x3/16 with a bit a plastic with holes for the axles (I copied the design from this http://www.superdroidrobots.com/shop/imageview.asp?file=TAM-023-000.jpg). Stuck a bit of expanded foam on the wood to lift above the tracks and stuck a prop board on top.
I did find a motor driver that would drive the motors that came with the gearbox - they are similar to your motors but it was much cheaper to change the motors (http://www.pololu.com/catalog/product/604) and use a L293D for the motor driver.
I used a 7.2V nicad I already had. The tamiya gearbox is all plastic gears but for this small a bot it works. Its a bit underpowered for the weight probably need to lighten it to ~1lb and run it from 9V nicad but I dont happen to have a 9V nicad and it works fine for its purpose.
I have since found other people have done very similar things see http://letsmakerobots.com/files/field_primary_image/P1000214-600.jpg
The other bot I didn't even use wood, the base was a bit of 8x4x1/2 foam board with 4 motors hot glued to it. Even the wheels were hot glued to the motor shaft (though they do come off after some abuse of the bot). Its about 1lb and is way too fast, though doesn't do any damage because its made of foam. Most of its weight is the same 7.2V nicad.
Until this I had always used lexan/plexglass or aluminium, but for small bots foam board works well and I will use it again.
The other thing I did was to put a IR detector on it and program it to respond to IR remote commands - allows it to be driven around like a RC car very cheaply using a normal IR controller. Its works for the trackbot but I can't control the other one fast enough before it hits something[noparse]:)[/noparse]
They both have a prop board driving the bots, though I need to fix the trackbot, its currently got a PPDB stuck on top - ran out of time. I need to add a L293D to a prototype board and replace the PPDB with it. Though it looks funny watching a PPDB driving around on a set of tracks.
The other area that is useful to know about is CPU design. In particular, how an instruction is decoded then used to fetch data.
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
BioProp: Robotics - Powered by Bioloids and controlled by the Propeller
▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
E3 = Thought
http://folding.stanford.edu/·- Donating some CPU/GPU downtime just might lead to a cure for cancer! My team stats.