New products: Assembled Zumo 32U4 robots

New products: Assembled Zumo 32U4 robots

Customers have been requesting an assembled version of our Zumo 32U4 robot kit ever since we released it in March, so it makes me very happy to be able to announce that we now have three pre-assembled Zumo 32U4 robots to choose from:

The three options differ only in their motors, and while the speed and torque vary across the three gear ratios, the peak output power is the same for all of them. You could maximize speed (i.e. 50:1 motors) or torque (100:1 motors), or perhaps you are looking for something in the middle (75:1 motors). The following table compares the gear ratio in more detail, with the first four columns showing specifications of the gearmotors by themselves and the last showing the measured top speed of a Zumo chassis loaded to a weight of 500 g:

Micro Metal
Free-Run Speed
@ 6V
Stall Torque
@ 6V
Stall Current
@ 6V
Top Zumo Speed
@ 6V and 500g
50:1 HP 625 RPM 15 oz·in 1600 mA 40 in/s (100 cm/s)
75:1 HP 400 RPM 22 oz·in 1600 mA 25 in/s (65 cm/s)
100:1 HP 320 RPM 30 oz·in 1600 mA 20 in/s (50 cm/s)

These three gearmotors are the ones we consider best suited for typical Zumo 32U4 applications (and many of our example programs are tuned to work with 75:1 HP motors), but we have many other gear ratios available that you can use when assembling the kit version of the Zumo 32U4 robot.

At this point, you might be wondering why it took so long for us to make an assembled Zumo 32U4 robot. Well, we have been working on several improvements to the Zumo 32U4 ever since releasing the kit, and we wanted to have them all in place before coming out with these more finished assembled products. The first improvement was to the sprockets, which changed from white with solid hubs to black with spokes. These new sprockets fit better on the motor shafts and make assembly and disassembly easier, and we think they just look cooler! They might also help you hide from your opponent’s IR sensors, but the color is of course no use against other sensing technologies like sonar.

Assembled Zumo 32U4 robot with older white sprockets (side view).
Assembled Zumo 32U4 robot with new black sprockets (side view).

The second improvement was to make a new component to hold and shield the IR LEDs used by the proximity sensor system. Without this, the LEDs are just supported by their leads and shielded by a piece of heat shrink (see the pictures above), and we wanted something better. Now the kit and assembled versions include a plastic LED holder that mounts directly to the front blade:

Finally, we have improved the blade. They are now stamped rather than laser-cut, and we have added cutouts around the general-purpose mounting holes so that they can be hand-bent to new angles as desired, independent of the blade angle. This new blade also has the chassis mounting tabs pre-bent to the appropriate angle, so that’s one less step required during assembly of the kit.

Original laser-cut Zumo 32U4 blade.
New stamped and pre-bent Zumo 32U4 blade.

And speaking of the kit, we still strongly encourage people to get the Zumo 32U4 kit and build it themselves. We designed the Zumo 32U4 to be a starting point, and building it yourself will make you more comfortable with customizing and enhancing it. Making it yourself will also make it a little more meaningful when your robot triumphs over the competition!

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