Let's Make Robots!

Lift robot

Collect small objects and place them in a basket.

Here it is the "lift robot". It will grab an object and after that it will place it on a basket. It uses the tracks of the very famous "yellow drum machine" and a lot of wood :) Actually I am planning to replace the wood parts by acrylic very soon.

The main body of the robot is made with the tracks of Solarbotics, a TV antenna piece, a part of a small toy, the Picaxe 28x1 and the battery holder. I plan to re-use this base for multiple robots...

Updated: This short video was recorded on July 03 ==>





Updated on July 03

Finally I got all the pieces assembled! The GM3 motor is doing a great job lifting the weight without trouble and connecting the second L293D was much more easier than I expected. I get a little problem though, the robot is rolling forward, that is why I will need to add some counter weight at the back or a ball caster under the frame. Hopefully this will be fixed on the next update. 



The grabber is made out of 2 gears of the Vex Gear Kit, one micro-servo and many acrylic parts.

It has been changed too.  All wood parts were replaced by acrylic. This process was a bit long but at the end I really like the look of the new grabber. To cut and bend the acrylic I followed the techniques on this link

First version of wood2nd version of acrylic [updated on July 03]




This is the top of the robot. This robot takes 2 driver-motors, 1 for the tracks and 1 for the pulley. Actually I got a lot of fun connecting the second driver-motor (the one on the blue mini-board) to the Picaxe 28x1. Also, I get some trouble finding the right motor to be controlled due to the starting current. Fortunately the GM3 gear motor solved my problem with the starting current...


Here some pictures of the GM3 gear motor that will pull up all the weight. I read on the documentation that the double-flat output shaft on the GM3 gear is ideal to take rotational load.



This is the frame and pulley that will support the grabber. I got the pulley and a metallic bar from an old Meccano and the frame is made out of some bars, glue and clues.

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great going...

hoping a video in Action soon...

I hope it will lifting objects in 2 weeks ;)

Nice work Juan. Have't seen a crane system on a robot for a while. 

The Vex Gear Kit is a nice finding - there is always a need for gears. The reuse of Meccano parts is a good idea too. I have just found a big bag of Swiss Meccano (Stockys) in a fleemarket. Got me tons of material to robotify.

Wooden robots have a lot of charme - where the acrylic look futuristic. Keep in mind that the acryl is a lot heavier than the wood you use (Wood density starts from around 0.4 * 10^3 kg/m3, Acryl starts from around 1.2 * 10^3 kg/m3). This can introduce different challenges on motor momentums and so forth...

Keep up the good work.

I didn’t though about the density of the acrylic, thanks for the advice, I will see soon how it does affect the operation of the crane.

The Meccano parts saved me some work! On the very first design I was using more of them but now just the 2 orange pulleys. I already tested the crane lifting a small weight and it worked very nice !



by the looks of this robots; depending on what you pick up it may tip forwards as there isnt much counter weight on the back, Sure you have the 3 motors, the extra block of wood and the batteries on the inside but they still may not be enough. Maybe adding an extra counterweight on the back could give it more traction(tho the tracks are good for that) and more downward force on the back.

This to me resembles a counter-balance/forklift in its basic form; i work with counter-balance/forklifts and i can tell you the back is pilled with extra weight. Also the higher the grabber+object go the more weight is needed to counter it.


Since I start working on this project I was worried about the counterweight, which is why I moved the 3 motors and the batteries to the back of the robot. Most likely you are right and it’s probably not enough... so I will have to find some extra weight and change a little bit the back part of the robot.

“The higher it goes, the more weight is needed to counter it” <- Hummm, that's a very good point and it will probably limit the weight of the object to be lifted...

BTW the “extra block of wood” was supposed to hold the original motor (the one with the start current problem); once I found the GM3 motor I thought about removing it but somehow it looks cool.

Nice robot Juan, cool to see something a bit different =)

The weight of the object in the gripper will be trying to roll your robot forward, pivoting around the front wheel of your tracks. To decrease the torque applied by the load, you could add something like a ball caster to the bottom of the lift, as far forward as you can. If you can put the ball caster halfway between the front wheel and the gripper, your robot only needs to weigh half as much to stay upright.

Honestly I never thought about the ball caster. I saw them before on some “Development Platforms” but I didn’t know how they were called. I just check the robot and a 3/8" diameter size could fit under the frame after a little work.

Nice advice!


Very cool, you've made nice progress. I'm curious, how will you detect objects to pick up? How will the robot find the basket? Good luck and have fun!

I think I will use the IR Controller from Picaxe to drive the robot, but I’m always open to suggestions.

The Picaxe guys call it: AXE040 PICAXE Infrared Upgrade Pack