First of all Yellow Drum Machine was my source of inspiration and after looking at all other users I have started making a Tank Servo Bot. I have just completed assembling the Tankservo bot kit from budget robotics. Currently working on assembling USB Picaxe28X1 module board (still waiting on the picaxe28x1 chip (alomost a week after ordering). My fellow robot hobbymate Duane (Octobot2) lended me one of his spare picaxe28x1 chip. Thank you Duane.
Will keep posting ...Good to join the group...
Thank you all.Atthaced is the new pic for sprocket and wheel.
CPU: Picaxe 28x1
Power source: 2- 4 AA batteries (4 RECHARGABLE FOR CPU AND 4 1.5V AA FOR SERVOS)
cool, I like that chassis, I saw it on the budget robotics site while I was ordering my octobot. Did it go together well? As soon as the month is up Im going to order one of casca’s tankbot chassis. (wife made me promise not to spend any more on robots this month!) My next bot will be a casca-based drum machine
nice job! i wanted to make a similar thing with my continuous servos but i don’t know how to. how did you attach the servo to the gears? (i know there are adapters but i’d have to order them)
(i can’t really understand from the picture how you did that)
wait wait, looking more wait wait, looking more carefully at them, the orange gears really look like those standard wheels by tamyia, which i managed to screw to my servos. i think i’ll give them a go too!
THe kit came with the tamiya wheels and sprocket for it. I have to use 2 supplied screws and nuts for each wheel to attach the sprocket on to the wheel. Then fit the wheel on the servo motor and tighten it with a screw (black).
i am concerned about the way i am concerned about the way you attach it to the servo. are you using a 4 horns servo horn (these are the “horns” i’m talkig about http://www.futaba-rc.com/parts/futm1980.html) or a 6 horns one?
I am using a output pin in series with 330 Ohm resistor for the signal/command to the R/C servo motor (which is modified for continous rotation). It has 3 wires Red (6VDC), Black (0 VDC/common) and White (for 5vdc control signal. on some servos it is orange wire).
To initiate the servos I am using servo 3, 75 (this will send a pulse of 0.75ms to output pin3 for every 20ms).
After this I am using servopos 3,120 (this command will move the servo to position 120).
Depending on what position you command the servo it will rotate in clockwise or Counter Clockwise direction.
For more information refer to Servopos command in Picaxe manual2.
It can be done as you suggest, but there is a much simpler way.
It’s so simple, compared to some motor control methods. I use the servo command to initilaize the servos in my initialization routine, and then the servopos command to control them in the program.
Once called, the servopos command operates in the background, with no loop required.
Read about the servo and servopos command in the Piacaxe Manual 2 for the basics, but they don’t talk about servos for continuous rotation.
With R/C servos that have been modified for continuous rotation, a pulse value of 150 supposedly is STOPPED. If you want the servo to rotate CCW, you send it a command less than 150. For example, 145 might be slow CCW. If you want the servo to rotate CW, you send it a command greter than 150. For example, 155 might be slow CW.
In practice, it seems that the stopped value depends all on the particular modified servo. I’ve seen 4 where STOPPED turned out to be between 130 and 135. If you’re willing to work on the servo, you can correct this. I prefer to just find where STOPPED is by a little experimentation, and adjust my speed commands from there.
Duane S
Wilson, North Carolina USA
P.S. I see that PSR_177 was replying at the same time that I was.
oh btw i bought my tank oh btw i bought my tank threads today, but the shafts provided are way too short. Next week i’ll buy the shafts set. But i am happy as i managed to stick the drive sprocket to my servo horn. :=)
