BWGunner
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20 ExcellentAbout BWGunner
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- Birthday 11/04/1970
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Cogthedog.com
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Location
Wausau
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Interests
Robots, dogs, art, writing, photography, hackmodding, wearable tech, Vlad Taltos and the number 42.
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SOME CORRECTIONS TO THE BUILD NOTES. I won't be publishing this again outside of COGtheDOG.com so glean what you can! :-D You need two of the T3-01 kits, build one entirely, drive it around. Isn't it cute? Remove the front fork and the big arm that holds the fork to the model, set aside. Disassemble the body. If you take the chassis main body halves and look at them laying flat, there's a fairly obvious space where, if you cut out a rectangle with a band saw or whatever (I used a table saw actually) you can notch out a rectangle that a standard servo slides into. Do that to both sides so the servos are back-to-back. It lines up with the hole the fork "neck" stuck out of. Check my photos, you'll get it. I built a mounting plate in the center next. Very thin spring steel, about the shape of the chassis main body. Drill some holes to pass bolts thru. I used an old plaster spreader, very thin and springy, but strong. I am planning on offering a custom build kit at COGtheDOG.com later this year. Assemble the body again around the steel plate in the center. Mount servos back to back on either side of the plate. I used 4-40 threaded rod. I bet you have access to better metric options in the UK. Now mount a servo horn on the mid-point of the SIDE of the fork arm. I used a horn on the side attached to the servo, but found M2 hex nut bolts the perfect length to feed through the fork "neck" and really bolt it all together. Assemble the second arm and do the same on the other side. You may note at this time my particular lack of measurements. That's because I didn't take any. I found most parts had "logical" locations, as thought Tamiya had anticipated most of this. The arm horns, for example, have a spot between two mounting nubs that very naturally fit the standard six-armed star shape servo horn. Lop off the arms you don't need. I used a ton of tiny screws to bold horns on both sides of the arm with an M2 thru them into the servo directly. Take the second set of "space frame" parts. Flip it around a few times so it faces the opposite way, hanging the former "radio platform" out the front. You might have to use a 4/40 threaded rod to pull the top one tight so the platform meets. Drill a 1" hole and mount an AdaFruit gimbal in it. bolt the two frames together over the chassis. Use slightly longer screws this time, you will be mounting two frames on top of each other. Look at some of the profile photos I have for details. I used existing holes where I could. You might want to upgrade the ADAFRUIT servos. Assemble the head. I used the battery cover/bash plate from the bottom as the snout and drilled a lot of holes. I put the radio up in the nose (freesky 6 channel is a PERFECT fit). We actually want a little weight up there, it helps the front wheels "set" a position when we change direction. Cantilevered head, you know. For the top of his head I cut down the body shell to just the headlight sockets and a small part of the A pillar for ears. I left the strip around the center and glued it around, like a strap, and that's the back of the head. Building the head is a total blur. Mess with the servos until you have a compact lower build. Attach the head with a few screws. Don't bother measuring, just punch holes and fill them with screws later for the Frankenpoodle look. I used a threaded 4-40 rod thru the head top servo bolted to either side of the helmet. Once it's all working shove lights and wires in open spots and hot glue lights where they look cool. Keep tucking until it's sorta clean looking. Jaw piece is screwed to the ADAFRUIT bracket. Since you lost the battery cover you might need to find a way to mount the battery. There are some convenient holes there for more threaded rod, but I just hot-glued it into place. The controller needs to have at least 3 mixes. I can think of a few ways I could use 4 or 5, but three is crucial. On mine I have throttle (1) on left stick up and down (sprung to center of course), hips on left (2) right and left, which is split out with a Y (with reverser and trim adjust screw) to the L/R head servo. Left arm (3) is right stick left and right and Right arm (4) is right stick up and down. 3 is mixed at 100% to 4 and 2. 4 is also mixed at 100% to 3 (AHA!) and 2 is split to head servo and reversed. Lastly head up/down is on a VR pot on the left. I use a FreeSky f6s and it's about the most basic controller you can use with this. Up stick left is go. Up stick right is head down (for speed, the forks are more stable laid flat, but turn on a dime standing up) and Down stick right is perky. Left on the right stick and both arms move as well as the hips and head. Reverse where you need to (oddly I only had to reverse the head) and it just works. He drives a bit like flying a plane...which leads to all sorts of fun geometry dynamics. Of course I have metal differential (ball) and axles, 7.2V battery and basic speed controller. I used a Traxxas brushed 370 and with full bearings it hits 25. C2 didn't use head servos at all, but used steering linkages for that terminator look. I connected them from the back of the fork "arms" to a floating head that looked around as I steered. It was pretty cool, but the servos are better. I used cheap metal gear servos at first and it worked very well. Loud and clumsy, but very functional. One hard tap on an arm, however, mashed the gears. I had to disassemble and reset, but no actual harm. On upgrading to APEX fast aluminum bodied servos ($25 each on Amazon) he has run flawlessly. Fast helps. I have some Tamiya Servo Savers on order to put in the shoulders, but they may not need it. One REALLY solid hit against a wall or really tall curb, however, and it will be messy. But that has not happened, it's just an irrational fear. I have wrecked him about a dozen times, and he seems very solid, and very flexible, at the same time. Lastly, I swapped out the Dancing Rider's rear servo arm (for tilting the rear engine) with 1/10 scale oil-filled shocks. They fit perfectly upside down. Do they help? I'm not sure. They dampen the hip servo in a way that can be frustrating sometimes and keeps him from really leaning all the way over. That said, they protect the servo from all the bumps when he goes off road...which is surprisingly frequent. Either way, they look too cool to take off for now.
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Thanks Wolfie! I was enormously pleased with the time stamp, thanks for noticing. This is the current write-up, but it's not long on details. https://www.tamiyaclub.com/showroom_model.asp?cid=133704 So I will write it out here: Take two of these kits, build one entirely, drive it around. Isn't it cute? Remove the front fork and the big arm that holds the fork to the model, set aside. Disassemble the body. If you take the chassis main body halves and look at them laying flat, there's a fairly obvious space where, if you cut out a rectangle with a band saw or whatever (I used a table saw actually) you can notch out a rectangle that a standard servo slides into. Do that to both sides so the servos are back-to-back. It lines up with the hole the fork "neck" stuck out of. Check my photos, you'll get it. I built a mounting plate in the center next. Very thin spring steel, about the shape of the chassis main body. Drill 4 holes to pass bolts thru. I used an old plaster spreader, very thin and springy, but strong. Assemble the body again around the steel plate in the center. Mount servos back to back on either side of the plate. I used 4-40 threaded rod. I bet you have access to better metric options in the UK. Now mount a servo horn on the mid-point of the SIDE of the fork arm. I used a horn on the side attached to the servo, but found M2 hex nut bolts the perfect length to feed through the fork "neck" and really bolt it all together. Assemble the second arm and do the same on the other side. You may note at this time my particular lack of measurements. That's because I didn't take any. Tricky part, take the second set of "space frame" parts. Flip it around a few times so it faces the opposite way, hanging the former "radio platform" out the front. Drill a 1" hole and mount an AdaFruit gimbal in it. bolt the two frames together over the chassis. You might have to use a 4/40 threaded rod to pull the top one tight so the platform meets. Use slightly longer screws this time, you will be mounting two frames on top of each other. Look at some of the profile photos I have for details. I used existing holes where I could. A note on the ADAFRUIT, it uses CHEAP servos poorly mounted. Mine blew out a gear on turning it on as it was mounted too close to the frame and just snapped when I turned it on. Of course I wanted to upgrade the servos anyway...so I did. Assemble the head. I used the battery cover/bash plate from the bottom as the snout and drilled a lot of holes. I put the radio up in the nose (freesky 6 channel is a PERFECT fit). We actually want a little weight up there, it helps the front wheels "set" a position when we change direction. Cantilevered head, you know. For the top of his head I cut down the body shell to just the headlight sockets and a small part of the A pillar for ears. I left the strip around the center and glued it around, like a strap, and that's the back of the head. Building the head is a total blur. Mess with the servos until you have a compact lower build. Attach the head with a few screws. Don't both measuring, just punch holes and fill them with screws later for the Frankenpoodle look. I used a threaded 4-40 rod thru the head top servo bolted to either side of the helmet. Once it's all working shove lights and wires in open spots and hot glue lights where they look cool. Keep tucking until it's sorta clean looking. Jaw piece is screwed to the ADAFRUIT bracket. Etc. Since you lost the battery cover you might need to find a way to mount the battery. There are some convenient holes there for more threaded rod, but I just hot-glued it into place. I don't swap batteries, I'm not professionally racing or whatever, and the battery seems to last about a half hour or more. I've put on 3 miles at a shot in the past, so it lasts long enough. Besides, the recharge wires are in an embarrassing spot and it makes me laugh to charge him. The controller needs to have at least 3 mixes. I can think of a few ways I could use 4 or 5, but three is crucial. On mine I have throttle (1) on left stick up and down (sprung to center of course), hips on left (2) right and left, which is split out with a Y (with reverser and trim adjust screw) to the L/R head servo. Left arm (3) is right stick left and right and Right arm (4) is right stick up and down. 3 is mixed at 100% to 4 and 1. 1 mirrors to head left/right. Lastly head up/down is on a VR pot on the left. I use a FreeSky f6s and it's about the most basic controller you can use with this. Up stick left is go. Up stick right is head down (for speed, the forks are more stable laid flat, but turn on a dime standing up) and Down stick right is perky. Left on the right stick and both arms move as well as the hips and head. Reverse where you need to (oddly I only had to reverse the head) and it just works. He drives a bit like flying a plane...which leads to all sorts of fun geometry dynamics. Of course I have metal differential (ball) and axles, 7.2V battery and basic speed controller. I used a Traxxas brushed 370 and with full bearings it hits 25. I need to work with the controller a little more. I think I can set "modes" that would allow me to turn off the mixes and kill the throttle channel. Doing this would let him be fully Animatronic. When he's set up this way naturally I've been able to get him to shake hands and do other dog tricks quite easily. Twisting the hips opposite the arms gets you a lot of character. I've also played with using steering arm linkage to bolt to the back of the head. No servos and you get the same ability to look around when you change direction...and a more industrial "terminator" style look. I used cheap metal gear servos at first and it worked very well. Loud and clumsy, but very functional. One hard tap on an arm, however, mashed the gears. I had to disassemble and reset, but no actual harm. On upgrading to APEX fast aluminum bodied servos ($25 each on Amazon) he has run flawlessly. Fast helps. I have some Tamiya Servo Savers on order to put in the shoulders, but they may not need it. One REALLY solid hit against a wall or really tall curb, however, and it will be messy. But that has not happened, it's just an irrational fear. I have wrecked him about a dozen times, and he seems very solid, and very flexible, at the same time. Lastly, I swapped out the Dancing Rider's rear servo arm (for tilting the rear engine) with 1/10 scale oil-filled shocks. They fit perfectly upside down. Do they help? I'm not sure. They dampen the hip servo in a way that can be frustrating sometimes and keeps him from really leaning all the way over. That said, they protect the servo from all the bumps when he goes off road...which is surprisingly frequent. Either way, they look too cool to take off for now. That's all my secrets. Let me see your build. Ask Tamiya to make an official kit. Let's get some dog races going!!
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How about this: I know it's SUPER long...
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You appear to be an expert on smelly things, I defer to the master! I was contemplating a sound device, but perhaps I am BARKING UP THE WRONG TREE!?
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I will get started on Epic Cog Video immediately. Slow-mo power-slides and jumps, full-speed blow by with debris and lens flare, terrifying crash footage everyone walks away from. You have given me purpose, Carter! You have a future in management! :-D
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Thanks all, you are too kind. Cog is a bit of a hacked together kit bash, but I adore him. I'm glad some others see the appeal. What I would like most, in case TAMIYA is listening, is to see this as a kit. Tamiya T4-K9 Cog the Dog anyone? IF YOU ARE A TAMIYA PERSON I WANT YOU TO MAKE THIS A REAL KIT. I will happily provide the specs, just make it. Please? Assuming I will hear nothing, so If there were a few people wanting the plans I could prolly put together a decent set of instructions. This place seems kinda set up as a marketplace, could I sell instructions or specialized parts to get Cog's all over the world?! That would be awesome. I have been surprised throughout this project how adaptable the T3 chassis is and how obviously it is compatible with Lego parts. Cog1 is a total Tamiya/LEGO build and it was surprisingly smooth. Is it ok if I add C4 as a Model in my own Gallery with T4-K9 as the model number or should I use T3-01? He's not really a T3 anymore so I'm not sure the protocol? Couple more photos just for fun. WOOF! Cog wants to play!
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BWGunner started following EXCLUSIVE Tamiya T4-K9 Dancing Dog
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Built entirely from Tamiya T3-01 Dancing Rider parts, my alternate build uses two sets. Even his head and eye pieces are directly out of the Tamiya T3 kit. Cog the Dog has 5 servos and a 6 channel receiver in his nose. An Adafruit micro gimbal moves the head, with left/right tied to the hip servo. 3 mixes coordinate arms and hip for four-wheeled leaning. A Traxxas 370, full bearings and an aluminum Hot Racing ball differential puts Cog at 25 mph. Please enjoy a little movie about Cog, an ongoing project that has taken many forms. The most successful one so far, unsurprisingly, is entirely Tamiya. https://drive.google.com/file/d/15Cv7sK0OL81QszjAD4fz_f8XaIIVgBop/view?usp=drivesdk
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