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Author Topic: Less than $50 Programmable Hexapod  (Read 4984 times)

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Offline KambeiXTopic starter

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Less than $50 Programmable Hexapod
« on: July 03, 2007, 10:41:55 PM »
Since $50 (and more, considering batteries, cables, etc) is still some money, let's build a cheaper robot with parts that can be reused in future projects and with possibility of expansion.

This one, however, is an hexapod (6 legs) controlled by 3 servos.


Comparing with the original $50 robot: (O= Original , H= Hexapod)



O: Hitec HS-311 servo
(modify the servo)    8.99    2    Servocity.com (Plus shipping)

H: 3 cheap chinese servos for the hexapod. The problem is these are hard to modify for continuous rotation but you can still try.
3 x servos (4.5g or 8g since they are small) = $9 (plus $4 shipping) shipped at bidproduct.com Savings = $9

O: 5V Linear Regulator    .48    1    DigiKey.com
KA7805ETU-ND

H: MC7805CT-BP 0.4 at digikey. $0.08 savings, every penny counts xD

O: ATmega8 AVR    3.66    1    DigiKey.com

H: ATTINY24-20PU , less memory and less input/outputs but is more than enough for starters. 1.91 at digikey Savings: 1.75

O: 28 pin DIP socket    1.26    1    DigiKey.com

H: We won't need the DIP socket.

O: 220uF+ Electrolytic
Capacitor    .28    1    DigiKey.com

H: You can use the same or any 47uF+ electrolytic capacitor you have (unless it?s too big of course).

O:.1uF Ceramic
Capacitor    .13    2    DigiKey.com

Not necessary, we will use the internal oscillator of the AtTiny. (0.26 savings)

breakaway male header    1.63    2    DigiKey.com

Not needed. 1.63 savings

340ohm resistor    .88    5 pack    DigiKey.com
PPC340YCT-ND
1.62Kohm resistor    .49    5 pack    DigiKey.com
1.62KXBK-ND
LED    .19    1    DigiKey.com
160-1034-ND
CdS Photoresistors    2.79    5 pack    RadioShack
276-1657

No changes here.

O: Grid-Style PC Board
with 356 Holes    1.79    1    RadioShack

H: Small Solderless Breadboard. I got one for $4 but the price will vary. Let's say $5. Extra $3.21

Enclosed 4 AA Battery
Holder (with On/Off switch)    1.89    1    RadioShack
270-409
9V Battery    .25    1    any store

O: 6v 1400mAh
NiMH Battery    16.50    1    onlybatterypacks.com

H: NiMH AA Charger Plus 4 1800mAh batteries $7.5 at eBay. $9 Savings

O:AVR STK Serial Port
Dongle Programmer    11.95    1    SparkFun.com

ATMEL AVR ISP Programmer For Parallel Port STK 200 /300 $10 Shipped (about $6 savings)


As you can see, the savings are many and there's still room for improvement, like purchasing only 2 servos and modifying them for continuous rotation (but the truth is these $3.00 servos are very basic and most likely you will break them if you try to make modifications.)

As Structure you can use a block of HDPE, wood or just using rubber bands to hold the servos in place. Also, since the base of the breadboard is adhesive, you can stick it to a hard surface like plastic or wood or even stick the servos to it (plus using the rubber band).

You can make the legs using ice cream sticks, wood, plastic or anything you can attach to the included servo braces.


And that's it, I will post some pictures when I recieve the servos since they take like 3 weeks to arrive to my country.

I hope you like the idea.



Offline Ai-bot

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Re: Less than $50 Programmable Hexapod
« Reply #1 on: July 04, 2007, 09:34:46 AM »
Hi...

I must say... very impressive under $50.
Is that before tax and shipping or after.
Nevertheless, I would like to see a demo video of this... sound fun. 8)


Offline S. Karim

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Re: Less than $50 Programmable Hexapod
« Reply #2 on: July 04, 2007, 02:15:34 PM »
tax shouldnt count, tax and shipping+handling is always there so it shouldnt be part of the the $50, since you're gonna exceed it.

if you need cheap servos, try https://www.unitedhobbies.com/UNITEDHOBBIES/store/uh_viewItem.asp?idProduct=2 - 208 oz/in for 6.69 a pop, but they are chinese so beware lol.

Offline sotu

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Re: Less than $50 Programmable Hexapod
« Reply #3 on: July 04, 2007, 02:40:10 PM »
Lol i bought 4 of those servos not so long ago,
Chinese or not chinese, doesn't mather, allmost everything is made in China/Japan now a day! :D
How to build a biped bot:

Offline S. Karim

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Re: Less than $50 Programmable Hexapod
« Reply #4 on: July 04, 2007, 02:46:23 PM »
Lol i bought 4 of those servos not so long ago,
Chinese or not chinese, doesn't mather, allmost everything is made in China/Japan now a day! :D
thats not what i meant. japan and china are tech gods, but in the servo industry, we defer "chinese" as "broken in 5 minutes" if you get what im sayin lol

Offline ed1380

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Re: Less than $50 Programmable Hexapod
« Reply #5 on: July 04, 2007, 06:00:52 PM »
Quote
O:AVR STK Serial Port
Dongle Programmer    11.95    1    SparkFun.com

ATMEL AVR ISP Programmer For Parallel Port STK 200 /300 $10 Shipped (about $6 savings)
good luck getting those to work
I've spent over $30 in trying to get mine to work. so $30+20=$50
Problems making the $50 robot circuit board?
click here. http://www.societyofrobots.com/robotforum/index.php?topic=3292.msg25198#msg25198

Offline sotu

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Re: Less than $50 Programmable Hexapod
« Reply #6 on: July 05, 2007, 03:04:14 AM »
Oh, ok. This is my first servos and people recommended those over at unitedhobbies.com so i took a chance, i hope they work ???
How to build a biped bot:

 


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