speed?

I just got my Sparki robots and they’re absolutely amazing!
I can’t wait to show these off. Your whole team deserves so much congratulations!
It is so easy to set up and will be an unbelievable teaching tool.

I have a question about wheel speed:
I noticed a speed parameter of 100 to motorRotate(). Any harm in turning it up?
Okay I admit I already tried it. 250 seems to work. Any technical problems here that I should be aware of?

Thanks!
-Ken

Thanks for the smiles :slight_smile:

I’m fairly sure its software-capped to 100. Anything more than that should just make it go to 100.

I’ll put down a note to change the code in the next update so that you can “overlock” it by going over 100. Do note that this is literally overclocking the motor, so special care needs to be taken.

In terms of the hardware limitations, the top motor speed is based on voltage. However, this doesn’t mean that you will get a higher speed in Sparki just by using a 9v battery instead of 4xAAs. It means it can go faster. The way stepper motors work, you make it take tiny steps in a row really fast. Each step is a set angle. This is great, because it means we know exactly how far its turned, regardless of what voltage is on the motors.

How fast you can make it step before it starts to turn is dependent on the voltage. Step too fast for a given voltage, and the motor starts to ‘slip’ and move all jerky. Right now we cap the stepping speed to be reliable for low-charged NiMH (the worst case scenario). That means ~1000 steps a second. You can see this in the Sparki.h file:

I remember when playing with this before, we got it to go up to ~1300 by using a 9v battery instead (the motor is not designed for that). Too much voltage though, and the motor heats up and burns out. The voltage regulator for the electronics can take 9v no problem, but it would damage the servo motor (6v reccomended max, so unplug it if you want to play with voltage). You can play with this STEP_DELAY value if you’d like.

Hi,

I looked at the code. Values from 0…255 will work.

I verified speed changes all the way up to 255 for the main wheels. It might not be good for the motors, but it works. The wheels run very smoothly at 255 using alkaline batteries.

-Jeff