Older blog entries for jkkroll (starting at number 28)

Deskpet Update & Pics

I finished laying out the PCB during lunch today. Maybe I can clean it up and get it out to BatchPCB for fab by tomorrow morning:

I finally got around to taking some pictures of the base:

Syndicated 2008-06-11 04:26:20 from robotguy.net/Blog

Deskpet Planning - Part B

1) I picked a battery: 230 mAh LiPo from All-Battery. 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.

2) The IS471F requires 4.5V but I want to run from a max of 3.3V. Looks like I’m going to need to find another solution for proximity detection.

3) Charge pump for the color sensor LED’s: MAX1595? I have used some of the Maxim capacitor charge pumps in the past and they work well.

Syndicated 2008-05-29 23:07:24 from robotguy.net/Blog

Deskpet Planning - Part A

I am working on the design for the Deskpet, and 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
  • Pushbutton


  • 2X Motors
  • Speaker
  • Wireless Data
  • OLED “face”

And here’s what I have so far for each:

Color/Line Sensor:

NECM005 RGB LED and TEMT6000 light sensor

Linear Hall Sensor:

Not sure yet. I like the 3 pin SIP devices from Allegro, but they need 4.5V. I would like to keep everything possible running from a 3V or maybe 3.3V supply.

IR Proximity Detect

2X IR LED’s and IS471F 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

CDS Cell or TEMT6000 light level sensor

Wireless Data:

Nordic nRF24L01 board from Sparkfun

Battery Level:

Voltage divider to ADC on the main processor

Battery Charging Circuit:

MAX1555 Lithium charge controller


SMT Momentary Normally Open SPST

2X Motors:

LB1836M Low Voltage Dual H-Bridge and 2X GM10 geared pager motors


Citizen Micro Speaker from Electronics Goldmine.

OLED “face”:

uOLED96 from 4DSystems. I have an older version than the one shown in the link with 8MB internal flash, and no uSD slot.

Still left to work on:

  • Battery - Size and mounting locations
  • Charging method - How does the robot find & connect to the charger?
  • Decide on a Hall Sensor
  • Find an LED charge pump since the G and B LEDs require 3.6 V

Syndicated 2008-05-28 19:54:59 from robotguy.net/Blog

More CNC’d parts

sprockets I have been playing more with my CNC machine and am working on some tiny treads for the GM10 motors. Here is a pick of the drive sprockets that I made. That is 1/4″ square grid paper that they are sitting on. I cut some prototypes out of nylon (yuck) then cut these out of some sample scraps of “Butter-Board“. That stuff cuts nice!
I made a female mold for the treads, but I don’t like it, so I’m going to redesign it. Maybe the sprockets also. I just got a 1/16″ end mill in the mail today so I can probably make them better now anyway. As soon as I tram my mill and get out the backlash, since my circles appear slightly out of round.

Syndicated 2008-05-20 21:36:36 from robotguy.net/Blog

Deskpet redux

As an ongoing project (see Flik previously) I have been working on a small robot that could live on my desk as a pet, hence the Deskpet moniker. I’ve done some research into how to give him personality, as well as how to add emotion (links soon). Last weekend I decided to play with my CNC mill and cut out a design for the body of my deskpet robot. I’ve 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 CNC’d master to make an RTV mold, and I molded a urethane copy:

Deskpet1 Deskpet 2

The body is shown with a Nickel for scale. The pics are really crummy because I used my cell phone, I’ll post better pics later. This will make a robot small enough to use for Micro-Sumo competition, and is designed around the GM-10 motors. I may end up selling these as just the body, or as a complete robot kit.

Syndicated 2008-05-13 21:57:58 from robotguy.net/Blog

The impossible takes a little longer…

Take a look at this: http://wiki.airsoftcommunity.co.uk/Gatling_Gun.

According to the Airsoft Wiki, what I am attempting to do is nigh impossible. Cool! That’ll make it even more fun.

Syndicated 2008-05-03 00:23:29 from robotguy.net/Blog

And now for something completely different…

So for anyone looking for an update on the Steampunk PDA: It’s dead. I was building it so that I would have something to sync with Outlook and remind me of appointments, tasks, etc. Well, the company gave me a Blackberry, so I now have no incentive to finish the PDA. Would it be cool? Sure. Would it be cool enough to entice me to finish it, even though I already have something that works? Probably not, but maybe someday. Who knows?

My next project is an automated sentry gun for the Defconbots competition at Defcon in Las Vegas this year. I was going to build a level 1 sentry from TF2, but a buddy here at work is already doing that. So…. I decided to one-up him and aim for a level 2 sentry.

Level 2 Sentry

Yep, complete with dual, counter-rotating gatling guns. I have picked up a few parts, enlisted a partner, Nate, who may be posting on the blog later, and even made a gatling-esque paperweight on the CNC mill:


Sorry about the image quality, I took that with my cellphone this morning.

Syndicated 2008-05-02 18:44:05 from robotguy.net/Blog

Well begun is half done?

My board showed up today from BatchPCB:

I managed to get the 3V power supply built and tested. Yay!

Tomorrow I will get someone at work to solder the processor on for me, as it is well beyond my skills (64 pin MLF).

Syndicated 2007-08-29 04:26:44 from robotguy.net/Blog

Route 66

I received the display (no pics yet :’( ). It is teeny, but the contrast is really nice. Last but not least, I just finished the routing of the PCB and should be sending it out for fab at BatchPCB by Friday.

I have three “airwires” left. The auto router choked on this board, so this was the best I could do manually. I added some vias so I could solder a jumper in to connect the nets.

Syndicated 2007-08-09 05:43:50 from robotguy.net/Blog

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