Older blog entries for egoo76 (starting at number 7)

9 Mar 2005 (updated 15 Mar 2005 at 14:03 UTC) »

I recieved the BASIC Stamp 2 OEM kit today and I am very excited! It only took a week to get here from Parallex with standard ground shipping. So I paid $36 and some change total. As I said before this is a kit that needs to be soldered, but I like to solder so no big deal. This will be the brain for my biped. I have been wondering about what type of soldering iron I should used (AC or Butane) to assemble the board. I figure that AC will be okay because I do not actually solder any of the chips, only the sockets. Besides, I have not done any fine soldering with my Butane torch/soldering iron.

I generally use the torch for soldering the frame on my robot. Their is quite a learning curve involved in the way I have chosen to assemble this thing, but I am slowly advancing.

I have been using metal clothes hangers for the frame, thread-all for the shafts, and various nuts and bolts. I cut the hangers into their three straight pieces and sand off the enamel. If I need to bend it I heat the metal up with my torch. It works really well but it is very time consuming. I chose this method because it is cheap, and that is really the only reason.

I have decided to use an empty tin coffee can for the 'body'. I have not decided if I am going to integrate arms into the design yet, probably not on this bot. I have also been working on the balance issue when the bot steps forward. I have come up with a sub structure in the 'calf' portion that will tilt on an axis further up the leg rather than having it tilt at the ankle. I'll keep it up and write later.


Well it has been a while since I posted an entery, so here it goes. I have been working a lot and getting much accomplished. I have the entire left leg frame built and the knee mechanics done. I still need to finish the foot and ankle mechanics. I have been working on the foot mechanics these past couple of days. I have decided to use a standard dc motor and reduce the speed with a dual worm gear configuration. I am pondering whether or not to use a stepper motor for the ankle or not. I probably will since that is what will actually turn the 'bot. I recently purchased some more gears and IC's from Nelnick.com, I specifically ordered a stepper motor controller. I have never used a stepper motor before let alone a motor controller IC, but it looks very interesting. I also purchased a STAMP 2 OEM kit today for only $30.00! It requires some soldering but that isn't to bad for the price. I have been looking at how many I/O's it will take to controll just the walking mechanics and it looks like a lot. I still need to add feed back and sensors too. So I have decided to construct several sub-systems to control most of the walking funtions and free up some I/O ports. We will see how that goes. I still need to consider power requirements and run time. Well, I will keep it up and write again.

I finally got a BASIC STAMP kit, it comes with a BS2 soldered to a 'Homework' board, which is a pc board with a small breadboard, associated MC circuitry, 9v plug, and a serial port. It also comes with several loose items: resistors, a transistor, a potentiometer IC chip, a servo, LEDs, pushbuttons, potentiometer, Cds Cell, and a small piezo element. On top of that it came with a CD full of stuff and a several hundred page book! I paid arount $90 for the kit which I bought from Radio Shack, and I am very satisfied indeed.

I am amazed at how easy it is to use, especially the programming portion. I hope to soon make my way through the instruction book and then begin to write a program for my robot. In the mean time I will of course experiment with different motor and sensory functions that are not included in the kit.

I am really no closer to completion with my robot mechanically. I am in a small room with thin walls and a tiny desk. But, I have been getting a feel for the atmosphere around the area and it seems pretty relaxed. I should be able to pull out some tools soon and begin working away! Finding time is another problem, I work longer hours here then at my home station. Well, I will update things as I go along. Oh yeah, still no internet in my room.

Well, I finally made it to my deployed location. I am in Florida for four months, not to shabby in my opinion. I currently don't have internet access for my leasure, so I am stuck trying to grab it when I can. I have been working on a couple things. I just recently scrapped my older legs and began working on a new pair. I changed the drive gear and the way it is set up. It looks much cleaner. I also found a BASIC STAMP project kit including a breadboard and some parts, but I don't have the money yet. I am going to be changing lodging locations soon, so hopefully I can get internet then. I really want to start publishing things on my web page. I need some feed back and suggestions. Until next time, keep coming until you get where you're going.

Well I have not been very busy working on my robot. I am leaving tomorrow for four months, so I don't know how much time I will have to work. Like I said I am in the military and periodically we have to go places to work and support operations. I am hoping that I will have opportunities to at least experiment with some of the electrical components. I am pretty sure fabricating anything will be out. Anyway I am still working on learning BASIC and creating a web site, but it is pretty slow.

I am still working on the ankle portion of the robot. It is a bit of a challenge getting the correct amount of movement, but I am sure I will get it. I am finding the joy's of tapping my own holes for the screws rather then using a nut at the end. I also found an old Siemens 8051 Microcontroller today with EPROM, S-RAM, and a character generator (but I am not sure what that is). I was pretty stoked until I realized that it is EPROM, not EEPROM, so I will have to work on getting it programmed (Anyone know how to do that?). Anyway it's late and I need to recharge. More tomorrow.

Well I completed the gear box for the ankle. I used 22 gauge sheet metal for the box. It houses two gears, the first is a 30T/10T gear that drives a 50T gear. I used a 3V moter with a worm gear as the power plant. Im estimating that I will need about a 1/4" of movement to balance the weight as the biped walks, but we'll see. One problem that I can already see is the size of the gearbox assembly. It is larger then what I had in mind, but I feel that I had to make it that size to achieve the gear reduction/torque that will be needed to move the weight of the bot. I was surprised at how quickly I was able to fabricate the box, only about 2 1/2 hours from start to finish. It used to take me about 3 1/2 to 5 hours to complete a gear box. I have also noticed that my accuracy is much better. Practice makes perfect. Thanks Goodrobot for the certification, it's appreciated. Well I am up pretty late so I am going to shut it down and recharge.

Well today I finished the left knee mechanics of my biped. Now I am going to start working on the ankle section, primarily the balancing mechanics. I am going to create a Web Page fairly soon, but now I am pressed for time.

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