Content in “indoor”

First Robot (Stole Frits' Design)

jklug80 — Fri, 16 May 2008 06:11:20 +0200

Primary image

What does it do?

Isn't he cute? He's also stubborn! I used Frits code and design for the first robot. I editted it to use the SRF05 instead of the other IR. The problem is debug is showing distance of 90+, but he still moves a centimeter, looks around, then goes forward. He stops every half second. Any ideas what is going on? It is hitting the Whichway subroutine and it shouldn't be. Range = 90 and dangerlevel = 20 it shouldn't halt the motors.

Symbol dangerlevel = 20 ' how far away should thing be, before we react?
symbol turn = 300 ' this sets how much should be turned
symbol servo_turn = 700 ' This sets for how long time we should wait for the servo to turn (depending on it´s speed) before we measure
symbol trig = 3 ‘ Define output pin for Trigger pulse
symbol echo = 6 ‘ Define input pin for Echo pulse
symbol range = w1 ‘ 16 bit word variable for range
symbol lrange = w1 ‘ 16 bit word variable for range
symbol rrange = w1 ‘ 16 bit word variable for range

main: ' the main loop
pulsout trig,2 ‘ produce 20uS trigger pulse (must be minimum of 10uS)
pulsin echo,1,range ‘ measures the range in 10uS steps
pause 10 ‘ recharge period after ranging completes
let range = range * 10 / 148
debug range

if range > dangerlevel then
gosub nodanger ' if nothing ahead, drive forward
else
gosub whichway ' if obstacle ahead then decide which way is better
end if
goto main ' this ends the loop, the rest are only sub-routines

Cost to build

$100

Embedded video

Finished project

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Time to build

Type

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Rebel, first attempt at building a robot.

GobliZ — Tue, 13 May 2008 20:12:09 +0200

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What does it do?

Line following, Driving around free with obstacle avoidance

This is a first attempt at building a robot. For now it is able to follow a line, and to drive around free with obstacle avoidance. In the near future I will program it to follow someone/thing, and in the far future I will try to let it solve a maze. ie. find it's predefined goal in a maze. The programming bit wasn't the hardest for me as I am studying Computer Science. It was the electronics that I really had to dive into. But in the end that was also not the hardest. I really enjoyed building my first robot and I think many will follow.

The parts that I used for this robots are:

Mini Bot Board II
Atom Basic Pro
2x Continous rotation servo
1x 180 degree servo
Ping))) Ultra Sound sensor
Tracker sensor (3x Infrared sensors)

I am already busy in designing a wooden chasis for it. So the Rebel II is already being desinged. I hope I can soon upload some videos of it running. Also I will make the source code available if someone is interested.

Tell me what you think of it? some suggestions for improvement, critisism, all is welcome.

UPDATE:

added 3 videos. In the first video rebel is following a line. In the second one it is navigating around and avoiding obstacles. In the third video, at the end, the batteries fell off and he dragged his guts around :P

Cost to build

$195

Embedded video

Finished project

Number

Time to build

30 hours

Type

wheels

URL to more information

Weight

First Real One...

Chris the Carpenter — Fri, 09 May 2008 04:00:56 +0200

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What does it do?

A nice, simple base running on good ol' Fritz code

Well folks,

Here's another entry based on Fritz's great code. One goal I had was to not have anything soldered directly to the main board. Instead I installed another board for hard connections and to allow me to expand in the future. I am thinking of this as a great, solid test bed for additional sensors and experimenting with code.

Cost to build

$200

Embedded video

Finished project

Number

Time to build

20 hours

Type

tracks

URL to more information

Weight

PhilBot (Aspiring Phil Collins Robot)

RobotRookie — Sat, 03 May 2008 23:16:29 +0200

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What does it do?

Drives around and finds something to drum on, while avoiding walls.

After seeing so many great drumming robots on LMR, I figured it was time for me to build one of my very own. I have never built a robot, or done anything quite like this, so this will be a learning process. I bought an Arduino a month or so back after reading about it constantly in my favorite magazine, MAKE. With a little help from TheCowGod, who also used the Arduino in his drumming robot, I have put together the start of PhilBot.

I also picked up a motor shield for the Arduino from Adafruit. It is a great way to use the Arduino to control multiple motors, and servos. It offers a lot of simple code to make the most out of your motors and servos. I used the body design of Brandon from Society of Robot. I used the same motor and motor mounts as well.

This morning I spent some time in front of the band saw and drill press and built the body. It was pretty quick and painless, and cleaned it all up with a bench sander. Overall, I am very pleased with the way it turned out.

I decided that before I worry about drumming, I need to get this thing to drive around, avoid walls, and find objects to drum on.

I bolted everything together and ran some code that I had written ahead of time. I am not happy with the wheels I have, but it is really hard to find wheels that will work well with a 3mm motor axel. I will probably have to fabricate something myself. I also quickly realized that my "looking" servo is far too slow. For the most part, PhilBot ran pretty well for its maiden voyage with all new code. There is still plenty of work to do, but he seemed to at least stay away from walls and obstacles, yet found a few things to drum on.

I got my new servo this morning. I picked up the Hitec HS-81 servo. This was nice and cheap ($15 at my local hobby shop), and it is fast! I cut a (somewhat sloppy) hole into the surface so the servo sits nicely inside and tapped some holes for a couple screws to hold it in place. After letting Philbot run around a bit, it quickly became obvious that my slow servo was the cause for a lot of the problems I was having before. Now it is time to fidget with the code...

I ran out of room for another motor on my motor controller (only 4, 2 for front drums, 2 for wheels). So, I am using the extra servo slot I have for the bass drum. I am also going to use the bass drum as my third leg while I am not drumming. When I find something to drum on, I will lift up the leg, the robot rear end will sit on a couple rubber feet, and it will turn into a drum. I don't know if it will work yet, as I am waiting for the JB Weld to cure. The ball is actually a top that you spin. I stuck the dowel end into a hollow aluminum pole. Also notice my new flat battery (6V 1000 mAh) that will fit nicely in between the two layers to run the motors/servos. Oh, and one more thing. The drive shafts will be trimmed down, just haven't gotten there yet, nor do I know if I am going keep these wheels...but I don't have any other options for a 3mm axel. More photos and hopefully a video once I get the two drumsticks installed and the code a little more fine tuned...

Cost to build

$100

Embedded video

Finished project

Number

Time to build

Type

wheels

URL to more information

Weight

My first robot - Ziltoid the omniscient

cjmtama — Sat, 03 May 2008 22:50:19 +0200

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What does it do?

Navigates and avoids objects

Ok, This is my first go at it. I will post more pics and some video as well.
Yes I did name him Ziltoid based on a Devin Townsend project. This is the first incarnation of Ziltoid here, I will work on a second one, probably just modify this one with speakers and sound. Ok, I had a little fun with the 2nd video. It does not explain anything, but it was fun to play with. Enjoy!

Ok, I can go over what I used now and costs. But first, thanks to Fritsl for the inspiration

and his how to build your first robot tutorial. Could NOT have done this or want to attempt

to do this without your guidance. The above tracks and chassis are from SUPERDROID

ROBOTS for $15. The chassis is solid and the parts that came with it to put it together

were tooled very well.

The two motors are from SOLARBOTICS, 143:1 ratio , 90 degree for

$11.50. I think next time I would go with a faster ratio, but this worked for a starter bot.

Since I really did not have some of the proper tools for this kind of project, I had to go

and get some basic stuff, like a glue gun, a better soldering iron and an extra pair of

hands/alligator clip circuit board holder. So add in an extra $40 bucks or so for that stuff.

Of course the whole thing is controlled by PIXAXE-28X starter pack with USB programming

cable. This was kind of the big single cost which was a total of about $73 from SPARKFUN.

The only problem I had, was once it came, the software CD was melted and un-usable.

No problem though, just went to the PICAXE web site and got the editor and manuals for free.

Add in L293D -Dual H-Bridge Motor Driver for about $3.50 from SOLARBOTICS. I could

not find the PICAXE servo upgrade kit anywhere that did not cost me an arm and a leg for

shipping, so I just used the 330 ohm resistor and had to do some searching for header

pins to hook up the servo and IR sensor. Found some 1X10 header pin connectors at

IEC for about $0.31 for 10. Problem here is that I bought like 10 sets for about $3.10

and paid over $9.00 for shipping. Lesson learned? Yea, buy whatever you can at the same

site at the same time and save on shipping. Used a Hitec HS-322HD servo from ROBOTICS

CONNECTION for $9.

I used the Sharp GP2D120 IR sensor with the IR sensor cable from ROBOTICS CONNECTION.

Cost for those was $9 for the sensor and $3 for the cable.

Other than the basic design change with tracks instead of wheels, the only other change

made was I added some header pins to the A/B motor outputs and connectors to the wires

from the motors so I could easily add/remove the motors and or board to another project

If I needed to. This was an awesome first time experience and thanks again to Fritsl and

everybody here for there input and knowledge. Hopefully this will help some other beginner

start on his, or her's robot. Now on to Ziltoid II.....INDEED HUMANS!!!!

Cost to build

$167

Embedded video

Finished project

Complete

Number

Time to build

20 hours

Type

URL to more information

Weight

The way we walk...

jka — Sat, 03 May 2008 00:16:05 +0200

Primary image

What does it do?

Walks straight ahead

This is an attempt to build a walking biped with only 4 servos, since that's what I have left right now. Since I don't have any video recording equipment right now, I'll try to describe how it walks. It start by tilting left to put all the wight on the left foot and lift the right foot. This is done by turning the left foot servo to the left, while turning the right foot to the right to support the robot as far as possible in the tilt, like this:

When the left servo turns further to the left, the weight will be on the left foot and the right leg will be lifted:

After the leg has been lifted, the robot will use the other two servos to move it forward. At this point, I always reach out for it, because it looks like it's going to fall:

Next step might be to add a gyro or acceleratometer, so it might adjust itself, if it's going to fall.

The "brain" is an Arduino that is mounted on a perf board. Only port 0-7 are connected because, the Arduino designers have, in their infinite wisdom placed the connector for port 8-13 half a unit from the 0-7 connector, so it won't fit on a standard perf board.

I'll add a video next week, when I get my hands on a camera that can record video (no, there is no camera in my phone and my webcam doesn't work)

UPDATE: Video available.

Cost to build

Embedded video

Finished project

Number

Time to build

Type

URL to more information

Weight

Gripper Bot

TigPT — Sat, 19 Apr 2008 21:25:24 +0200

Primary image

What does it do?

Will be able to catch things with a grippe

Foto Album

I'm thinking in make a robot where i can make my things my way.. so i'm making it to be line follower, but to future update to gripper.

Last updated foto

From now on i will start to upload fotos to here.. to don't spam the main topic.

http://picasaweb.google.pt/tig.rodrigues/GripperBot

Cost to build

Embedded video

Finished project

Number

Time to build

Type

URL to more information

Weight

KALSABER

Krumlink — Sat, 12 Apr 2008 23:02:07 +0200

Primary image

What does it do?

Follows and Tracks A light Source

KALSABER is an autonomous Light seeking robot that can Track a light source with a hacked servo head, and will proceed to follow it.

KALSABER v1.0

Krumlink's Autonomous Light Seeking Advanced BEhavior Robot v1.0

Unfortunately this robot is Currently Disassembled, but I took many pictures, and The circuitry is still working.

Kalsaber uses 4 CDS Cells in a 2 pair configuration that is then fed back through a Conduit that feeds into the robot's Circuity. It has 3 Transistor H Bridges, 1 sensor board, and 1 "Motherboard". It is all custom built circuitry, and the servo has been hacked for easy hook up. The Servo Head has it's H Bridge mounted on it, with the Sensor head on it's Side (look at the pictures). I spent a lot of time trying to get the thing working, then it worked great. I usually just use the Head, since it works nearly perfectly. Unfortunately no Video exists of it operating, but it worked great :)

All point to point wiring xD

Cost to build

$20

Embedded video

Finished project

Complete

Number

Time to build

3 hours

Type

wheels

URL to more information

Weight

Boe-bot for The Chair Challenge II

TigPT — Tue, 08 Apr 2008 19:18:22 +0200

Primary image

What does it do?

It complete the requirementes asked in "The Chair Challenge II"

Find out my new project here.

Hope it respect all parameters in the challenge:

"The Chair Challenge!"

Requirements:

Robot can be placed in any position and place operator prefers before start
Robot must then spin around it´s own center at least 10 times before step 3. (so we know it is actually navigating on it´s own)
Now the robot should try to drive around each of the 4 legs of a chair, like the orange arrow

Result:

Robot was placed at the chair left side, in it direction.
The robot spins 10 times over itself before start the task.
The robot drives around each of the 4 legs, like the orange arrow.

Picts:

Code:

"The Chair Challenge!"

Requirements:

Robot can be placed in any position and place operator prefers before start
Robot must then spin around it´s own center at least 10 times before step 3. (so we know it is actually navigating on it´s own)
Now the robot should try to drive around each of the 4 legs of a chair, like the orange arrow

Result:

Robot was placed at the chair left side, in it direction.
The robot spins 10 times over itself before start the task.
The robot drives around each of the 4 legs, like the orange arrow.

Code:

'(I know it is not that cute.. it may be simplified, but i was afraid of gaping time to finish the task, since I'm with school projects in hands.. maybe I tune it up later)

' {$STAMP BS2}
' {$PBASIC 2.5}
' {$PORT COM6}

'---------- VARS ----------'
pulseCount VAR Byte
irdetectleft VAR Bit
irdetectrigth VAR Bit
fase VAR Byte
'---------- TEST ----------'

'---------- START ----------'
GOSUB Spin '5 Spins on it own center
GOSUB Spin '5 Spins on it own center
fase = 0
'--------- MAIN CODE ---------'
DO
FREQOUT 8,1,39500 'activate IR
irdetectleft=IN9
FREQOUT 2,1,39500 'activate IR
irdetectrigth = IN0
'-- states machine --'
SELECT fase 'find beguin position
CASE 0
IF (irdetectleft=0) AND (irdetectrigth=0) THEN
fase = fase + 1
LOW 1
ELSEIF (irdetectrigth=0)THEN
GOSUB Slow_Spin
HIGH 1
ELSE
GOSUB Soft_Spin
ENDIF

CASE 1 'turn around the first chair leg
GOSUB Slow_Around_Leg
HIGH 1
GOSUB Forward
GOSUB Around_Leg_Large
GOSUB Forward
GOSUB Slow_Around_Leg
GOSUB Slow_Around_Leg
GOSUB Slow_Around_Leg
LOW 1
fase = fase + 1

CASE 2 'find and sping on the 2nd leg
IF (irdetectleft=0) AND (irdetectrigth=0) THEN
GOSUB Slow_Around_Leg
HIGH 1
GOSUB Forward
GOSUB Around_Leg
'GOSUB Forward
LOW 1
fase = fase + 1
ELSEIF (irdetectrigth=0)THEN
HIGH 1
GOSUB Slow_Forward
ELSE
HIGH 1
GOSUB Slow_Forward
ENDIF

CASE 3 'find and sping on the 3rd leg
IF (irdetectleft=0) AND (irdetectrigth=0) THEN
GOSUB Slow_Around_Leg
HIGH 1
GOSUB Forward
GOSUB Around_Leg
GOSUB Forward
GOSUB Slow_Around_Leg
LOW 1
fase = fase + 1
ELSEIF (irdetectrigth=0)THEN
GOSUB Slow_Forward
ELSE
GOSUB Slow_Forward
ENDIF

CASE 4 'find and sping on the 4th leg
IF (irdetectleft=0) AND (irdetectrigth=0) THEN
GOSUB Slow_Around_Leg
HIGH 1
GOSUB Forward
GOSUB Around_Leg_Large
GOSUB Slow_Around_Leg
GOSUB Slow_Around_Leg
GOSUB Slow_Around_Leg
GOSUB Forward
LOW 1
fase = fase + 1
ELSEIF (irdetectrigth=0)THEN
HIGH 1
GOSUB Slow_Forward
ELSE
HIGH 1
GOSUB Slow_Forward
ENDIF

CASE ELSE 'stop at end of task
DO
GOSUB Stay
LOOP
ENDSELECT
LOOP
'---------- SPIN ----------'
Spin:
FOR pulseCount = 0 TO 255
PULSOUT 13,850
PULSOUT 12,850
PAUSE 45
NEXT
RETURN
Soft_Spin:
FOR pulseCount = 0 TO 10
PULSOUT 13,770
PULSOUT 12, 770
PAUSE 45
NEXT
RETURN
Slow_Spin:
FOR pulseCount = 0 TO 5
PULSOUT 13,755
PULSOUT 12,755
PAUSE 45
NEXT
RETURN
'---------- BASIC ----------'
Stay:
FOR pulseCount = 0 TO 255
PULSOUT 13,750
PULSOUT 12,750
PAUSE 45
NEXT
RETURN
Forward:
FOR pulseCount = 0 TO 40
PULSOUT 13, 650
PULSOUT 12, 850
PAUSE 20
NEXT
RETURN
Slow_Forward:
FOR pulseCount = 0 TO 50
PULSOUT 13, 740
PULSOUT 12, 760
PAUSE 20
NEXT
RETURN
'---------- LEGS ----------'
Around_Leg:
FOR pulseCount = 0 TO 110
PULSOUT 13,735
PULSOUT 12, 850
PAUSE 40
NEXT
RETURN
Around_Leg_Large:
FOR pulseCount = 0 TO 150
PULSOUT 13,735
PULSOUT 12, 850
PAUSE 40
NEXT
RETURN
Slow_Around_Leg:
FOR pulseCount = 0 TO 10
PULSOUT 13,735
PULSOUT 12, 850
PAUSE 40
NEXT
RETURN

Cost to build

$130

Embedded video

Finished project

Complete

Number

Time to build

5 hours

Type

wheels

URL to more information

Weight

390 grams

Little Drum Machine

TheCowGod — Mon, 07 Apr 2008 23:36:15 +0200

Primary image

What does it do?

Drive around and find interesting things to drum on

Here's my latest project. I liked Frits' Yellow Drum Machine so much that I decided I wanted to build one of my own. I'm working on the physical construction first -- once I have somewhere to mount the batteries and logic board, I'll glue on some drumsticks and start working on the drumming code. When my SRF05 arrives in the mail, I'll add that and start working on navigation. The last step will be adding the sampling board to record and play back sounds. Well, that's the plan, anyway :)

Photos

My brother is a woodworker, which is nice to have access to :)

Look at that, dadoes and everything!

The robot's "superstructure," looking much nicer than the way I first planned to make it (Frits-style -- keep adding glue until it stops moving :). Batteries go in the bottom compartment, circuit boards in the upper one, and maybe a giant speaker glued to the top :)

Gluing it up...

The base so far

The underside

The breadboarded circuit. The blue board is a Pololu Micro Dual Serial Motor Controller for the main tank tread motors, and the three transistors will each switch one of the "drumstick" motors on or off. The green wire towards the top will be for output, maybe an LCD or a speaker.

One of the "drumsticks". I found that 1/4" aluminum tubing seemed to give a bit of a ring without being too heavy.

Sure, that's clear as day, right?

Main body glued together. It's a little taller than I had imagined, but ah well.

Rear view

2008/04/07

Reworked mounting of circuit boards to free up more space, and glued on the first drumstick motor.

2008/04/09

Now he's got a "bass drum".

Bass drum motor detail

2008/04/10

He can rock out now. Similar to what I assume Frits did, I hacked a little sampling circuit board, removing the pushbuttons and soldering wires to let the microcontroller trigger the playback and record functions. Now he can record his beats and play them back in a loop while he jams along with them.

Sampling circuit board detail

2008/04/13

My first PCB! A board for the SN754410 that lets me turn the sonar left and right.

The solder side. (I need a finer tip for my soldering iron)

Fabricated a bracket to mount the SRF05 onto the motor.

Rear view

He's now mostly complete. I want to add one more drumstick up front, but otherwise everything's there.

Once I'm happy with all the circuits, I'll probably solder it all up a PCB to eliminate that rat's nest.

Underside

2008/04/15

After gluing on the second front drumstick, I decided that the construction was complete, and I was reasonably sure that there wouldn't be major new components added anymore. So I decided to rebuild the circuit on a PCB "shield" that would fit right onto the Arduino rather than using a breadboard with dozens of loose jumper wires running between the two. To further clean things up, I cut up a ribbon cable from the same old 486 that donated its speaker to this project, and used that to connect my PCB to all of the sensors, motors, etc around the robot. The result is a much cleaner setup, and if I want to remove the Arduino for whatever reason, I can simply pull off the two ribbon connectors, rather than having to deal with tons and tons of wires and then later having to re-figure out which wires go into which I/O sockets. It took me quite a bit of thought to come up with a layout for all of the pins that grouped common functions together and made the circuit small enough to fit on that small PCB, and I'm actually pretty proud that I managed to fit it all in. What's even more amazing is that, after spending 6 hours soldering everything up, it actually all worked perfectly! I expected there to be tons of hard-to-track-down problems after doing so much soldering in such a small space.

One last shot of the circuit on the breadboard . I won't lie -- the real purpose of this shot was so that if I soldered up the circuit and it didn't work, I'd have some sort of documentation of what the original circuit looked like so I wouldn't have lost everything :)

That's a mess. Good riddance.

I didn't take any pictures of the soldering process, but here's the top side of the completed board. SO much cleaner. At the bottom is the 9-pin socket for the Pololu motor controller. Above that are the three transistors and diodes for the three "drumstick" motors. The screw terminals at the top are for the motor battery supply, and the pins on either side are for the two ribbon connectors. In the background, you can see the paper where I enumerated and grouped together all of the pins I needed to connect, in order to figure out what should be close to what, etc.

Bottom side of the PCB, where all the action is.

It slides right onto the Arduino, and mates with the Arduino's I/O sockets.

The paper where I laid out all my connections before soldering.

2008/04/17

With the construction done, I shifted my attention to improving the code. The coding I had done for playing drums worked pretty well for music that I hardcoded by hand, but as I started thinking ahead to how I wanted him to be able to 'write' his own drum beats, I realized that I'd need something a little more programmatical and less music-oriented. So I took a page from real drum machines, and I redid my drumming routines to get rid of the explicit calls to play notes of varying lengths. Now, instead, I just divide a measure into 8 beats, and my drum patterns are 4 measures long, so that's 32 beats per pattern. I have 4 "instruments" (bass drum, two drumsticks, and a click from the speaker), so a pattern can be represented by an array of four 32-bit long integers. When I want to play the pattern, I just loop over each bit in the integer, and play the drum if it's a 1, or don't play the drum if it's a 0. I had to do some fun bitwise math to look at individual bits from each integer, but it works, and now I just need to come up with four integers and I've got a new pattern.

I came up with some quick and dirty code to let him come up with his own patterns -- each time I measure left/center/right distance with the sonar, I stick each of those measurements into bass drum, snare, and hi-hat. It shows promise -- they actually sound pretty musical just like that. This whole 'coming up with his own patterns' thing will need some tweaking, to guide the patterns closer to musical and away from 'random banging', but it seems doable.

The part that I continue to have trouble with is the *&$king navigation. At first I thought I had found the problem when I realized that, since I had mounted my two drumsticks so far forward, my SRF05 was actually detecting those sticks most of the time when it looked left and right, so it was literally like he was wearing blinders. I cut the hot glue and re-glued the two motors angled farther back, so now that's not a problem anymore, but I still have trouble getting realistic numbers out of that sensor. Lots of times it will be like 8 inches away from a wall and pointing straight at it, and the sensor reports that the distances are something like (60 // 8 // 45) or (13 // 8 // 146) or things like that. The direction that is facing the wall head-on tends to work well, but the views to the sides seem to be completely unreliable. I added some debugging code to have it beep out the three distances through the speaker like the tracking devices in the movie Alien, with the pitch getting higher as the detected distance gets closer. That works really well for letting you know immediately how far away it thinks things are, at least relative to each other. And that has shown me that most of the time, it's getting totally incorrect numbers, which is why he can never manage to find anything to play drums on.

I know these sonar sensors have trouble when they're hitting a wall at an angle and things like that, so I'd expect little flaws every once in a while which wouldn't bother me, but this was pretty much just useless. Then I realized that one problem might be the fact that those little Solarbotics GM10 motors turn about 60 degrees in either direction, so his side views were actually getting close to looking completely sideways. That meant that, even if he's facing the wall head-on, the side views end up looking really far away, so the robot has to find himself really close to a wall before his side views can actually hit the wall:

So I glued small plastic tabs onto the motor, to limit the rotation of the head down to only about 40-45 degrees in either direction.

This seems to work MUCH better. I set him down on the ground, and he quickly lined up with the wall, drove up to it, and started drumming. Awesome. Now I can move on and continue working on improving the coding. So, some final shots of the completed robot:

The sampling board didn't have any holes in it for mounting with standoffs, so I borrowed more inspiration from Frits and just hot-glued it onto the side. And he's right, a strip of glue DOES work well to hold down the loose wires. How did I survive this long without a hot glue gun?

Ahh, I like that so much better than those loose wires everywhere.

I moved the microphone away from the bass drum motor, because it was picking up the whine of the motor louder than the drumming itself.

2008/04/19

I give up. The little plastic tabs I glued onto the sonar motor weren't working as well as I'd hoped, plus after just a few minutes of testing, they broke off and the motor went back to scanning its full 120-degree range. I just couldn't get the robot to find things worth playing on -- he spent all his time wandering around, snaking back and forth, never actually reaching any walls. It was especially frustrating since my 'object following' code for Harry The Discbot works so well. Harry, of course, has his "eyes" on a real servo, not a GM10 motor. So I gave up trying to get it to work with the GM10. I can certainly appreciate the pleasure of building complex things with really simple tools, but I just wasn't making progress and it wasn't being fun anymore. So a few minutes with an X-acto knife, and the GM10 is outta there. I first glued on the Hitec HS-55 micro servo that I'd bought on a whim to use on a later project. Once I started testing it though, I was surprised by how slow it was. I had just kind of assumed that, since it was such a tiny servo, it'd be really fast, but apparently it's geared down to be closer to the speed of a full-size servo. It worked just fine for locating objects, but I really wanted to try to preserve as much of the "zip" of the GM10 as possible. It probably doesn't help that the HS-55 is Hitec's "economy" model. When I looked up the specs, I found that sure enough, the speed of the HS-55 at 4.8v is 0.17 sec/60 degrees, whereas most of their nicer servos, just a few dollars more, are in the 0.12-0.14 range (and even down to 0.9-0.10 still at reasonable prices). There are $80 servos that do it in 0.04, but that's not what I'm looking for.

So I bought an HS-81, which is rated at 0.11 sec at 4.8v, brought it home, and tested it, and was much happier with the speed. It's still no GM10, but I'll happily trade a little bit of zip for actually being able to find the damn wall. So I broke out my X-acto knife AGAIN (I've gotten good at removing hot glue), removed the HS-55 and glued down the HS-81, and now we're in business. I ported over my object-following code from the Basic Stamp-powered Harry to the Arduino, spent some time adapting it to this purpose, and at last! He can actually reliably find things to drum on. Ahh.

With the GM10 gone, I no longer needed the motor driver PCB I spent so much time and thought making, so off that comes from the side of the robot. Ah well, I'm sure I'll find use for it in another project.

I've also made some more progress on his 'writing drum patterns' subroutine, so it sounds a lot more like music. I've posted a new video above showcasing his new talents. There's still work to be done, of course -- there's a slight gap between patterns for some reason, and I've got plenty of ideas for improvements to the code. But now he's finally starting to behave like a proper drum machine :) Now I'm having fun again. And I hope Frits isn't too disappointed that I gave up on the GM10 -- I'm impressed as hell that he managed to make his work so well with one. I guess I'm just not as skilled a roboticist as him :)

I'll keep updating this as I continue working.

Cost to build

$150

Embedded video

Finished project

Number

Time to build

20 hours

Type

tracks

URL to more information

http://binrock.net/photos/?rid=896