Dash Robotics

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Picking a Motor

Hey everyone, 

   As we mentioned, we're sorting out all the components that will make up Dash. We've got the chassis and electronics basically sorted, but one of the last remaining pieces to decide on is the motor. Dash sports two electric motors, one driving the right legs, and one driving the left. These motors are small, only 6 or 7 mm in diameter (about 1/4 inch), light, and easy to work with. They're what's called a coreless brushed, DC motor. The coreless part means they accelerate very quickly, something we think is important for Dash. Of course, not all motors are created equally, and they vary greatly with respect to cost, power, and efficiency.

   When selecting a motor, there is often a trade-off of battery life and speed. We think Dash should be fast. We also think he shouldn't need to recharge after 5 minutes of playtime. The first thing we test for is speed, and the second is battery life. One of the motors exceeded our expectation.

For the battery life testing, we wanted it to be as "real" as possible, so we put Dash on a leash, gave him a fully charged battery, and let him run until he could run no more.  

We tested several motors, sometimes with Dash running, and sometimes with Dash on his back. 

By comparing different motors, we can get a sense of which has the best tradeoff of battery life and power. With this fast motor, Dash had almost 15 minutes of battery life while running both motors at full blast continuously. From previous experience we know that actual play time is much longer than that, so you shouldn't be recharging Dash too often. 

In the meantime, we've been doing lots of user testing so that Dash's chassis is fun and easy to put together. Work also continues on our mobile app and electronics. Check here for more updates every week!

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