Let's Make Robots!

Ebay mixed bag of robot bits

I mentioned on SPANR's page that I bought a bunch of robot bits on ebay some time ago and I started playing with them recently. This blog is my way of keeping track of what I got and some thoughts on what I can do with it.

First off, the biped.

(30/12/12) I pulled out what I thought was a Lynxmotion biped robot to figure out what was working with it. Further investigation revealled that it was a Lynxmotion biped torso with a SSC-32 servo controller mounted to it and two Dagu 6-servo robotic arms where one would expect the legs to be. The grippers were seperate and missing their servos but the end of the arm was obviously supposed to mount a smaller servo in what would be a very odd orientation for a biped robot's leg. Four more servos were mounted to the torso at the shoulders with another two servos hanging off by their cables. Not knowing what to do with all of this I removed one of the 'legs' and mounted the gripper to it. I connected the SSC-32 to my PC via a USB-to-serial converter and ran Lynxmotion's Servo Sequencer and promptly found that a servo I had employed in the gripper wasn't working. It had a blown transistor/FET at the motor connection so I swapped it out with a working servo which had been missing the top half of the housing (gears exposed). As there was no spare screws, nuts or bolts with my robot parts I made do with zip/cable ties to finish assembling the arm (zip ties hold the world together!).

On New Years Eve (31/12/12) I figured out that the 'spare' servos attached at the shoulders, together with the loose brackets are in fact the legs of a Biped BRAT. I tried reassembling the BRAT following the assembly instructions on the Lynxmotion website. I had to disassemble the pan/tilt and buy some nuts and bolts but I was able to assemble the BRAT biped.

ebay photo of 'biped'

Two 6-servo arms (minus two servos in the left arm), a biped torso and a biped BRAT.

(04/01/13) I've been playing with the biped BRAT and the sequencer software, making him stand on one leg and wiggle his foot. Not too sure where I want to go with the brat. I really like Tman's conVERSE, which is a modified brat. For now I'll tinker with animating the brat in the sequencer and maybe look at exporting the servo keypoints to an arduino sketch. SPANR has some mounting points intended to receive servos so I'm a little curious if he could accept the 6-servo arm(s). Perhaps a custom claw/tool on the second arm instead of simply replacing the missing/broken servos.

What else do we have here?

I have managed to extract some magic blue smoke from a Dagu 4-channel motor controller that was already looking a little damaged before I started to play with it. If it was working I would have put that to use on the Rover 5 robot base (4 motors, 4 encoders) which just needed a new set of wheels for the tracks (I haven't ordered them yet as I want to try my hand at 3d printing some mechanum wheels first).

Tentatively on the look-out for a 2-channel motor controller (or 2 H-bridges) for a Heng Long 1/16 'Bulldog' tank base. Can't find any info on the motors although I can find identical motor & gearbox sets on ebay. Original electronics were gutted though the transmitter was included (might gut the circuit and connect to the switches/potentiometers (photo below) for a head start on a robot controller). Also included with the tank base was the airsoft BB-firing gun and the motor & gears for turning the turret (no bodywork though).

Micro-update 18/01/13: Ordered an Arduino mini to replace the original electronics in the transmitter. Will use an APC220 wireless to connect with the robots.

Transmitter for the Heng Long tank. Pots on the right stick (left of this photo) and two-way switches on the left stick.

Wireless camera mounted on a servo pan/tilt with a receiver for a TV (briefly tested, doesn't appear to be working).

Sanwa Conquest MkII FM Transmitter & Receiver (Model aircraft radio control), 6 channel (though don't know how the 6th channel is operated, 5th channel is a gear raise/lower switch, remaining four channels operated by two sticks). There are three Sanwa servos with this, they have a slightly different connection arrangement (Power, Ground, Signal instead of the standard Ground, Power, Signal), which lead to some confusion when I tried testing some non-Sanwa servos with this receiver.

Wait, there's more?

Yup, there was some electronic goodies too. Within SPANR's project box was found a Dagu 4-channel motor controller and a DFRobot Mega1280. stEve received the DFRobot Duemilanove. DFRduino I/O Expansion shield with SD module, Input Shield (thumb joystick + two push buttons), LCD Keypad Shield. A Chinese bluetooth module. A pair of 1km range APC220 wireless serial modules with one USB adapter. A 3-axis accelerometer Gyroscope L3G4200D breakout board. And last but by no means least, a Dagu IR Compound Eye.

5 x 7.2V Ni-Mh batteries with a charger and several connectors. SPANR came with a 12V battery & charger.

Breadboard jumpers, M/M, M/F & F/F patch leads. A PS1 controller. Two books: Introduction to Arduino and Robot Builder Bonanza.

ebay photo of entire collection


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