BoeBot vs. ActivityBot
David Betz
Posts: 14,514
I gave my ActivityBot to my son and now I'm wondering if I recreate it by taking an old BoeBot that I have and adding the Parallax Digital Encoder for Boe-Bot (#28107) kit to it. Is that all that is necessary to have the same platform as the ActivityBot? I have an ActivityBoard that I can mount to the chassis. I'm just wondering if BoeBot + Parallax Digital Encoder kit equals ActivityBot. Or should I bite the bullet and buy another ActivityBot kit?
Comments
There's more to the AB than just the encoders. The encoders from the AB and the BOE-Bot are different. The AB's wheels have more holes and are in different locations than the holes in the BOE-Bot's wheels.
Besides the encoders, control board and wheels, the AB also has high speed servos. I think the AB also comes with a Ping.
There's a list somewhere of the parts needed. Hopefully someone will add a link (I'll look for it myself).
ActivityBot Encoder Wheel and Tire (#28114) $3.99 each
ActivityBot Encoder Kit (#32501) $37.99
I don't see the faster motors though unless these are the ones:
High Speed Continuous Rotation Servo (#900-00025) $16.99 each
If that's it then I guess a BoeBot can be converted to an ActivityBot (minus the ActivityBoard and Ping) for $79.95
I think those are the ones.
I have just about all the parts to convert a BOE-Bot to an ActivityBoy myself, except for the encoders. I just can't bring myself to pay $38 for a pair of encoders. I've been working on some homemade encoders to hopefully work with the AB. I still haven't tested them with the AB wheels yet but if they work, I'd be willing to send you a pair. I'm pretty sure I have an extra set of PCBs and parts to go on them.
I made my encoders quadrature encoders but they should also work as single channel encoders by leaving one pin disconnected. They might not work as well as the official version since Phil thinks normal encoders will have trouble with ambient lighting.
Thanks for the offer of your encoders but I decided to give Parallax the business and I order their servos, wheels, and encoders. Good luck with yours! I wish I had the ability to build my own parts like that.
The Prop BOE and the ActivityBot have different ADC chips, so you'll need code changes for that.
dgately
You don't absolutely need the Learn tutorials to use a BOE-Activity Board, of course, and you can always create your own routines and code. But the tutorials and libraries already provided make for a quicker start.
David,
The ActivityBot also has the 5 cell AA battery holder. I'm not sure what the BOEBot has. The High Speed Servos can use 7.5v .
Tom
David
Edit: Since I had to amend my order, I decided to go with the Li-ion battery pack! :-)
Dave,
I just want to make sure you know there are two kinds of Li-Ion battery packs. One is small and should fit under the Boe-bot/Activity Bot and the other is the size of an Activity Board and would need to go on the top side of the robot. I believe the two boards work the same way.
This is the one I intend to order. Its documentation says it works with the BoeBot. I assume it mounts underneath like the battery pack does. Has anyone used this Li-ion pack with an ActivityBot?
http://www.parallax.com/product/28989
That's the one that goes on top. Here's a picture of this larger board on my PropBOE-Bot.
This one (pictured below) fits where the original battery pack was. I'd think the smaller one would be a better match for your needs.
David, this is the board that Duane was talking about. It fits under the BOE-Bot and replaces the AA battery holder.
http://www.parallax.com/product/28988
Duane has the regular power pack which is bigger so that's why he had to mount it on top.
The power pack is nice because the charger is built into the board so you only need to plug it in.
Ray
I don't have the smaller pack but what I understand is both smaller pack and the larder pack pretty much do the same thing. They both charge the cells in place.
When I ordered my Li-Ion charger, the small one hadn't come out yet.
1. Have magnetic screwdrivers handy (space is very tight and dropping tiny screws over and over is amazingly frustrating).
2. Don't try to do the conversion without first taking most of the unit apart (including the tail wheel ball). Or, if starting off un-assembled or partially assembled, put on the Li-ion pack at the same time you are mounting your new servos. Certain screws need to be in place before the Li-ion unit can be installed.
This sure seems strange.
Did you watch the video on the product page? It looks like they so the pack installed.
I've been having trouble fitting the Li-ion PCB between the two nuts that hold in the servos and the encoders. The instructions for the BOE-Bot battery back say to remove those entirely but then the encoders aren't held in very securely. How did you handle this?
I've attached a picture of what the 4 servo/encoder screws look like from the outside of the chassis because I can't show the inside without taking my poor KittyBot (http://instagram.com/p/gJUfpqgjUN/) apart. (I will though if you need to see the setup more clearly, just ask.)
Three screws should have the lock nuts on the inside, and the one that the Li-ion pack sits on has the lock nut on the outside. Is this helpful?
Thanks!
David
I haven't ever personally had to trim the board to make it fit; the only other thing I can think of is that there may be a very minor difference in chassis size due to the age of your kit. On my bot, I have maybe 1/16" clearance or less between the board and the tail-wheel end of the chassis.