TiggerBot II Robot

TiggerBot II is a small treaded robot platform. Included are instructions for building the plastic treaded platform and a custom printed circuit board containing a microcontroller and sonar sensors.

This is a relatively complicated project that is still at the late-prototype stages. Every attempt has been made to keep it simple to build but, well, robots are hard. Furthermore, this project will set you back somewhere in the $150-$250 range, depending on where you buy the parts. Continue at your own risk.

Specifications:
> chassis material: cnc laser cut acrylic
> drive motors: 2x continuous-rotation rc servo
> battery: 2.2Ah 9.6v rechargeable NiMH
> nav sensors: 5 way ultrasonic sonar
> cpu: AVR Mega32, 16MHz
> programming: RS-232 serial port bootloader
> code: written in c, compiled with gcc-avr
> expansion port: 5v/1A, gnd, 2x adc, i2c

for latest news see http://robotarmy.org/

Step 1 Background

This was my first robot, built in 2002 when I was a freshman in college. I named it TiggerBot because it was black, orange, and stupid. It was flawed in several important ways. TiggerBot II is a substantial redesign; it uses the same treads kit but is superior in all other ways. Pictured below are the original TiggerBot, several obsolete TIggerBot II prototypes, and the current prototype.

Comments

[Jr Hacking kid]

how do i make it with 3mm plastic if urs is in 6mm plastic

[Shifrin]

Wow! This is truly amazing, you could make hundreds off this if you made some sort of a kit for it, I know I would definatly buy it! Great Instructable! -Alex

[Iohan]

the circuit board is too complicate try to put someting that can be handmade in home

[e.c.kern]

i hand made it at home. maybe the circuit board isn't the problem.

[Iohan]

i can´t see how i can draw the circuit lines using that picture

[Patrik]

Any particular reason why you chose to rob those poor defenseless servo's of their servohood, instead of just buying a set of DC motors? Other than that, looks like a great project! Are you still using the same electronics for the latest prototype? Have you felt any need for sensors in the rear?

[e.c.kern]

also. i have a new pcb prototype now, but it looks mostly the same. i considered sensors in the rear -- the sonar multiplexers are eight way so three more transducer pairs can be added very easily -- but decided against it because (1) the transducers are a nontrivial fraction of the total cost (2) board space is limited (3) it would have required routing the highly sensitive receive circuits through the highly noisy rear section of the board.

[e.c.kern]

yes, dc motors would have been somewhat better. i chose servos mainly because they are widely available and cheap when compared to dc motor + h-bridge.

[Patrik]

I have to admit to being woefully ignorant regarding servo's and h-bridges. How essential (and expensive) is the h-bridge for this sort of design?

Otherwise, it seems like you could use something like this: Twin-Motor Gearbox. Same speed at a higher torque and less than 1/2 the price...

[jinventive]

I think he keeps the servos becuse they have more controllable speed, they have mor torque and can be controlled more precisely than regular DC motors.

[zaro12345]

I am assuming that he moded the servos because they are easyer to control than continous dc motors. also, it's cheaper.

[bre]

Wow, that is a very impressive array of sensors. This project rules!

[e.c.kern]

it's just five rx/tx pairs -- which isn't really that many -- my last robot had 8!

[frank26080115]

Amazing chassis design! I'm planning my next robot to be all aluminum but I'd really like to try out Ponoko now. Can we see the Eagle files and source files? Or did I miss the link somewhere?

[e.c.kern]

the eps for the acrylic, which is what you need for ponoko, is linked off step three. i priced a similar earlier prototype on ponoko and it was about $25 each if three are packed together on a size-2 sheet. i haven't shared it on ponoko because i have never actually ordered a copy there myself so i can't promise that anything would fit. unfortunately both of the board prototypes i've had made so far require several greenwire fixes so i haven't posted those designs yet. i'm getting pretty close, though.

[GorillazMiko]

Dang.. looks incredibly difficult. Very nice job by the way.

[e.c.kern]

actually i went pretty far out of my way to keep it easy to build. the circuit board looks complicated mostly because it's all through-hole components, which are harder to fit but easier to solder.

[Bongmaster]

is it available in kit form? :3

[e.c.kern]

unfortunately i don't have time to operate a mail-order business. maybe if there's enough interest someone else could kit some -- the full parts list is included.

[Jr Hacking kid]

and how can you make the servos go faster ?

[Jr Hacking kid]

dose Canal Plastics have a web site cuze i want to make a chasie like urs

[Jr Hacking kid]

could you make it radio controled it looks cool as a rover with a cam on it becuze thats wat i might do with it is it ok i can mod this

[ELMo_0007]

How long do the treads work out to be? I'm working on a project where they might be helpful but there are size restrictions.

[e.c.kern]

they are 16" total length per side; this uses the entirety of the kit. various shorter lengths are possible.

[frank26080115]

the treads comes in sections of varying lengths, some are about the length of a finger. You link them together at the end to create a loop however long you'd like.