Look Ma, No USB! Untethering the WeDo

To keep the WeDo simple and easy to use for younger children, the WeDo doesn’t have an intelligent brick in its building materials. No intelligent brick, so no programming and no power. The USB hub is there to provide both from the computer. But, wouldn’t it be great to be able to untether some WeDo creations? Especially cars?

This WeDo car has an AAA battery pack for power.

This WeDo car has an AAA battery pack for power.

Well, it is possible. At least, it is possible to give WeDo creations power, if not programming. The key is to use elements from the Power Functions line of products. The Power Functions use exactly the same cables as the WeDo (and not the same as the NXT or EV3). So, by using one of the battery boxes, your WeDo creation has the power to propel itself beyond the reach of the computer. There’s are trade-offs though. As there is no programming, the sensors cannot be used. A programme cannot be written that controls how far the car will go. And, the battery boxes are large and heavy, necessitating some sophisticated building. This is not a project for grade one students.

This WeDo car uses an AAA battery pack for power and is turned off and on with a control switch.

This WeDo car uses an AAA battery pack for power and is turned off and on with a control switch.

There are three battery boxes in the Power Function line. The 8881 battery box is the heaviest and largest and takes six AA batteries. The smaller and lighter 88000 uses six AAA batteries. Finally, the 8878 is a rechargeable battery box that uses the same charger as used by the NXT and EV3 kits. In this photo, a car based on the design from [here] has been modified by removing the USB hub and adding in the battery pack. As there is only one switch on the 88000 and 8878, the car can only go in one direction. However, the switch on the 8881 allows you to power the car in two directions. Still not enough fun? Well, add in the 8869 Control Switch and controlling the direction (back and forth only) is now possible with the 88000 and 8878 battery boxes. But, the Control Switch will likely be built into the car as the cable is not very long. The ideal goal is remote control. Can the WeDo meet this challenge?

This WeDo car has a battery pack for power, two motors and an infrared receiver.

This WeDo car has a battery pack for power, two motors and an infrared receiver.

The most fun might be using one of the remote controls with the 8884 IR Receiver. The 8885 and 8879 remote controls allow you to turn the motors (and lights) on and off. In addition, the 8879 provides power level (speed) control as well. By using a two-motor design, it is even possible to have the WeDo car turn. Before rushing out to buy this equipment, check whether anyone has a Lego Train Set or Lego Technic Set that included Power Functions products. For this post, the 8293 Power Functions Accessory Kit was tested. This kit includes a motor, battery box, control switch, lights and a few building pieces. However, I then found out that my sons’ train set included the 88000 battery box, IR receiver and 8879 remote control. All inter-connected fine.

Resources

The following building guides were used as the basis of the cars featured in this post:

This WeDo car has an AA battery pack for power and an infrared receiver.

This WeDo car has an AA battery pack for power and an infrared receiver.

 

 

 

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