View Full Version : [Project] Deskpet

06-13-2008, 11:25 AM
I'm new here, but I guess I'll jump in with both feet...

As an ongoing project (see Flik (http://robotguy.net/blog/2007/01/03/latest-project/) previously) I have been working on a small robot that could live on my desk as a pet, hence the Deskpet moniker. Iíve done some research into how to give him personality (http://robotguy.net/blog/category/personality/), as well as how to add emotion (links soon). A couple weekends ago I decided to play with my CNC mill (http://robotguy.net/blog/2008/05/21/cnc-setup/) and cut out a design for the body of my deskpet robot. Iíve been working on this design for a while so it was just a matter of loading and running the program. Then, one of the guys at work used the CNCíd master to make an RTV mold, and I molded some urethane copies (click on any pic for a larger version):

http://robotguy.net/deskpet/tn_dp_trio.jpg (http://robotguy.net/deskpet/dp_trio.jpg)

http://robotguy.net/deskpet/tn_dp_green_back.jpg (http://robotguy.net/deskpet/dp_green_back.jpg)

I decided to build a prototype with a minimal configuration to get started. I plan to use an ATMega128 processor because I have several laying around. Here are the required input and outputs:


Color/Line sensor
Linear Hall effect sensor
2 way IR proximity sensor
Ambient light level sensor
Wireless data
Battery level sensing
Battery charge input


2X Motors
Wireless Data

And hereís what I have so far for each:
Color/Line Sensor:

NECM005 RGB LED and TEMT6000 (http://www.sparkfun.com/commerce/product_info.php?products_id=8348) light sensor. I have some ideas (http://robotguy.net/notebook18-19.html) on how to use this to detect position on a "playmat".

Linear Hall Sensor:

SS49E linear Hall sensor from Honeywell. Works with 3 to 6V input. I plan to place this in the front and use it to detect magnet-enhanced "toys".

IR Proximity Detect

2X IR LEDís and IS471F (http://www.junun.org/MarkIII/Info.jsp?item=46) modulated detector. Could also be used for IR homing beacon for charging station. To avoid interference with the proximity detect, sending a specific pulse from the LEDs would trigger the charging station to transmit a response.

Light Level

TEMT6000 light level sensor

Wireless Data:

Nordic nRF24L01 board from Sparkfun. (http://www.sparkfun.com/commerce/product_info.php?products_id=691) Eventually, the Nordic chip will be incorporated into the PCB itself.

Battery Level:

Voltage divider to ADC on the main processor

Battery Charging Circuit:

MAX1555 (http://www.sparkfun.com/commerce/product_info.php?products_id=674) Lithium charge controller


SMT Momentary Normally Open SPST (http://www.sparkfun.com/commerce/product_info.php?products_id=8720)

2X Motors:

LB1836M (http://www.semiconductor-sanyo.com/search/property.asp?clcd=41&prod=LB1836M) Low Voltage Dual H-Bridge and 2X GM10 geared pager motors (http://www.solarbotics.com/products/gm10w_deal/)


Citizen Micro Speaker (http://www.goldmine-elec-products.com/prodinfo.asp?number=G13780) from Electronics Goldmine.


230 mAh LiPo from All-Battery (http://www.all-battery.com/index.asp?PageAction=VIEWPROD&ProdID=1639). If I raise the standoffs by about 0.05″ I can fit it between the motors and the PCB or I could add a small shelf to the back end of the frame, kinda like a penny-racer.

I have finished the layout of the board (1.75" X 1.75") and sent it off to BatchPCB for fab:
http://robotguy.net/tn_dp_pcb1.jpg (http://robotguy.net/dp_pcb1.jpg)

Meanwhile I am working on the code for the wireless module.

That's it for now. I keep updates on my blog, http://robotguy.net/blog/ (http://robotguy.net/blog/), but I'll try to keep this updated as well. I also have more of my older planning info in my robotics notebook (http://robotguy.net/notebookcover.html) if anyone wants to look through that...

06-13-2008, 12:44 PM
That's awesome! I was just thinking when I woke up this morning about something similar, and had started whiteboarding a bot about 1.25" square. What are your final measurements looking like, do you think?

06-13-2008, 08:33 PM
I've been following this project in your Robots.net blog. Very cool.

So you are molding the bodies? Is it easy to make more? Would you by any chance be interested in selling a robot body...? I've always been looking at those little motors on solarbotics, but that has to be the coolest design I've seen with them.

Again, an awesome project.


06-14-2008, 04:53 PM
What are your final measurements looking like, do you think?

1.89 Wide X 1.825 Long X 1.35 Tall
http://robotguy.net/tn_dp_size.jpg (http://robotguy.net/dp_size.jpg)

I've been following this project in your Robots.net blog. Very cool.

So you are molding the bodies? Is it easy to make more? Would you by any chance be interested in selling a robot body...? -Fergs

Oh yeah, I forgot that I'd set up robots.net to track my blog.
I am considering selling either the body by itself or a complete kit with motors, wheels, pcb, battery and docking station. However, since you are the first to ask, send me a PM, and I'll send you a body to "beta test." I could use the feedback.

06-14-2008, 07:42 PM
i would be interested in a kit when ya get there.

06-14-2008, 10:31 PM
1.89 Wide X 1.825 Long X 1.35 Tall

BTW I designed this to be small enough to use for Micro-Sumo competition (http://robogames.net/rules/all-sumo.php).

06-19-2008, 03:11 PM
Double post. Oh, well.

I built up a quick pre-prototype using a single 230mAh LiPo, a Baby Orangutan from Pololu and a Nordic wireless module and key-fob from Sparkfun:
http://robotguy.net/deskpet/tn_dp_proto_rc.jpg (http://robotguy.net/deskpet/dp_proto_rc.jpg)
Family and friends have been having a lot of fun driving it around.

My end goal is to let the 'bot talk to a base station connected to a PC. I REALLY want to write an RF bootloader, so I can reprogram without touching the 'bot. This is the hardware for the base station ( Still need to write the software and firmware):
http://robotguy.net/deskpet/tn_nordic_rx.jpg (http://robotguy.net/deskpet/nordic_rx.jpg)

06-19-2008, 03:23 PM
Very cool.

Office sumo.

I've got a little skull that would look right awesome on one of those...


06-28-2008, 01:42 AM
I'm a sucker for micro little guys... that's way too cool!