I’m getting back into robotics after a long break, I bought my first lynxmotion kit from Jim 10 years ago (3 servo Hexapod 1 ) and had a few more 4 and 6 legged friends built throughout the years, I think my Quadrapod projects are still posted even (Extreme Quadrapod by Andrew Alter). Anyway, thats my short intro, glad to be back.
The Johnny 5 kit caught my eye, so I’m lookin to pick one up here shortly. Just wanted to know if anyone here was a J5 owner, and if they would provide any insight on how they set theirs up ie: RC, Atom, BS2 controlled.
I’m thinking Atom/SSC 32/Playstation controller for some flexibility.
Johnny 5 is very new, and I don’t think anyone here has actually built one yet. Several of us want to though. If/when I build a Johnny 5, I’d want it to be able to bend and reach forward all the way to the floor.
Is reaching to the ground in front currently “out of reach” given its design? Looks like the torso could bend forward a bit if needed, might need to bump up the servos in the torso to do it well though
The design was intended to be more expressive, rather than utilitarian. If you build the two servo waist with both servos with their horns to the front the robot can reach the ground, but it will be more work for the servos.
Is there another servo aside from the 645MG that you would suggest for those two in the torso if I wanted a bit more strength there? I didn’t see anything in your list of servos that looked like a decent upgrade without going over $100 per servo. Do you think the added stress of setting up the servos like that would be too much for the servos to handle?
You might want to try Tower Pro MG995 Servos. They provide 20-25 lbs max torque EACH and sell from $15.00 to $18.00 each not including shipping cost.
I have not tried them so I can’t comment on quality or longevity, but at such a low cost you might want to give 'em a try.
Someone in these forums built an entire scout with these servos and said they were a bit jittery, but in the video, it looked only minor during brief moments between moves.
It seemed ok for that scout equiped with 20+ servos so two of them for a rover that only needs to work for one joint can’t be all that bad. It’s not like these servos need to keep a rover ballanced or anything.
I have not tried them so I can’t speak with any real confidence but you are only talking about two of them. Come on Eddie, you can get off the floor now, and brush your self off. Geez!
Can you share your experiances using these servos? I would like to know.
Admittedly my opinion / avoidance is strictly based on the multitude of posts on rcgroups.com where I first encountered them, then follow-up research based on the “come now they can’t be that bad can they” thought process. I don’t think I would spend money on them or could in good conscience recommend them to anyone else without the heads-up preface as there were that many instances of people not happy with them. I still think they might be good mechanical fodder for OS conversions. I also think in a .40 IC R/C trainer where the motor vibrations out shake the servo jitter they might be ok. The video you reference looked at times like the bot was a parky patient and the guy himself commented on the servo jitter, and that it was not unexpected.
I would guess, and this is just a guess, that if the torque was always applied in a single axis like the shoulder or maybe the elbow of an arm that the jitter would be less because the pid error would always be in one direction. I’m not sure how easy it would be to align two of them in parallel like the shoulder of the l6 arm or the j5 base. The j5 base seems like it would go over center a lot so you would have two fairly strong gear trains twitching against each other everytime that happened… which doesn’t sound healthy for the servos, the rest of the robot sitting 4-8" above the pivot, or your battery life.
You still have to buy your BRAT servos though, right Mike? Give-em a try!
I did some research on these cheap monsters and have ordered 6 of them…
No, just kidding. I went on some RC forum and read a load of personal reviews. It seems like a crap shoot. You might get an ok one, or you might get a DOA, or one that works for five minutes. I have never looked in to these servos since I have always had my heart set on Hi-Tec servos. Since actually researching the TP MG995s I would play it safe and save up for a quality servo(s).
As far as having two servos joined together with different overshoots and different resolutions would most likely put both out of commission in a hurry with them being so “breakable” to start with.
My apologies for not having my facts straight. Ok Eddie, resume the ROFLMAO.
I used 5645 servos on our J5, the one in the ZZ-Top Low Rider music video. 8) They do have more power. You could always revert to the robo-one trick of moving the arms to build up momentum to lift the torso up easier. Honestly, I haven’t tried to lower it down enough to pick up something from the floor. It may not be as difficult as you think.
I’m doing pretty good these days My old Hexapod 2 PE and ‘extreme’ Quadrapod got stolen when my house got broken into about 4 years ago, a lot of time and money lost there, so I took a bit to get back into robotics, but your Johnny 5 model sparked that old flame. You should be seeing an order from me in the next few weeks here
I know you’re probably a busy guy these days (I remember calling you 10 years ago when I was 13 and picking your brain about the original 3 servo hexapod I bought haha) but if you get a chance could you see how well the J5 model can lower down to pick an object off of the floor? I’ll pick it up regardless, I’m just curious if I’m going to need to make some changes to make it happen.
I second that on the Tower Pro servos. They are complete garbage. They can produce the torque they spec but they are all very jittery, especially under load.
I bought one of Jim’s very first Robot Arms a long, long time ago. So long ago that I don’t actually remember the year but it was one of the first runs.
And I too am back into robotics after a long absence and have already built a Robobnova 1 and a have a Bioloid kit I am playing with.
But there is something about the Johnny5 kit that is so appealing that I might push the ‘Buy’ button today and get it on order. It looks like it has so much potential for all kinds of additions. In fact, I just ordered earlier this week a POB-Pack 2 : POB-Pack 1 + POB-Proto setup from POB Technology and now plan on using it on my Johnny5. Looks like a great fit.
So, let’s keep the thread alive and share what we can.
I am building a Bioloid/Johnny-5 type robot using the tracked base.
Well, I was going to post a link to the YouTube video, but apparently Lynxmotion has a spam-bot prevention policy that prevents me from doing so, at least for today…
If you really want to find the video, go look on my blog, which is at the website huv (with www and com in the right places, and /blog as the trailer).
Its controlled from my PC through wifi to an onboard gumstix verdex, which is talking to the Bioloid bus through an FT232 USB chip. In the video I’m controlling it with a joystick, but of course the plan is to move it to full blown autonomous eventually.
Ordered my J5 kit today, should be here by the weekend
Planning on using the smirf bluetooth setup to control it from my laptop for now, will eventually move to an onboard pico-itx setup w/ wifi and control it via RDP on my home network.
) and had a few more 4 and 6 legged friends built throughout the years, I think my Quadrapod projects are still posted even (Extreme Quadrapod by Andrew Alter). Anyway, thats my short intro, glad to be back.
