Scioly.org

Ed63 wrote:Brushless motors are great, but a brushed motor is just fine for this event. We're using a brushed motor and battery directly connected and getting times in the 1.75 to 1.80 sec range. We have been the fasted car at both invitationals so far this year. Sometimes simpler is better.

As one data point, I can confirm that brushed motors work fairly well for this challenge. The winner at our state competition used 6 x AA batteries running both an
Arduino and a MOSFET motor controller coupled to a 6V motor that also included an encoder. Wheels were pretty small (probably 2.5 inches or so). Time was about 2.2 seconds and was around 5 cm away from the target on the second run.

azkbisfb wrote:

Ed63 wrote:Brushless motors are great, but a brushed motor is just fine for this event. We're using a brushed motor and battery directly connected and getting times in the 1.75 to 1.80 sec range. We have been the fasted car at both invitationals so far this year. Sometimes simpler is better.

As one data point, I can confirm that brushed motors work fairly well for this challenge. The winner at our state competition used 6 x AA batteries running both an
Arduino and a MOSFET motor controller coupled to a 6V motor that also included an encoder. Wheels were pretty small (probably 2.5 inches or so). Time was about 2.2 seconds and was around 5 cm away from the target on the second run.

I doubt any of the top 10 cars at nats will be brushed motor cars, since from what I've seen top 10 will be around 1.4-1.7 sec and pretty accurate, and I don't think brushed can get times that high.

azkbisfb wrote:

Ed63 wrote:Brushless motors are great, but a brushed motor is just fine for this event. We're using a brushed motor and battery directly connected and getting times in the 1.75 to 1.80 sec range. We have been the fasted car at both invitationals so far this year. Sometimes simpler is better.

As one data point, I can confirm that brushed motors work fairly well for this challenge. The winner at our state competition used 6 x AA batteries running both an
Arduino and a MOSFET motor controller coupled to a 6V motor that also included an encoder. Wheels were pretty small (probably 2.5 inches or so). Time was about 2.2 seconds and was around 5 cm away from the target on the second run.

Were they rechargeable AA's? You can't pull much current from alkalines - especially AA size.

Yes. They were the rechargeable AAs you can get pretty cheap at Costco.

Today, we got a lovely state-specific rule that says programming from a computer is considered remote control and will result in participation points only. While we are waiting for clarification about what this actually means, I am prepping for the worst case scenario that this applies to microcontrollers on the car as well.

For those of you not using a microcontroller, would you recommend a wingnut braking system, and is it equally reliable as in other events such as Scrambler? I remember doing something like that for Battery Buggy but did not believe it was that great.

samlan16 wrote:Today, we got a lovely state-specific rule that says programming from a computer is considered remote control and will result in participation points only. While we are waiting for clarification about what this actually means, I am prepping for the worst case scenario that this applies to microcontrollers on the car as well.

For those of you not using a microcontroller, would you recommend a wingnut braking system, and is it equally reliable as in other events such as Scrambler? I remember doing something like that for Battery Buggy but did not believe it was that great.

It might just mean controlling it during the run, but in case you arent allowed to bring a computer to the event and upload a program (which is complete BS), then try adding a visual feedback (LED display or something) and then making it so you can use a button to change the setting/distance.

Bazinga+ wrote:

samlan16 wrote:Today, we got a lovely state-specific rule that says programming from a computer is considered remote control and will result in participation points only. While we are waiting for clarification about what this actually means, I am prepping for the worst case scenario that this applies to microcontrollers on the car as well.

For those of you not using a microcontroller, would you recommend a wingnut braking system, and is it equally reliable as in other events such as Scrambler? I remember doing something like that for Battery Buggy but did not believe it was that great.

It might just mean controlling it during the run, but in case you arent allowed to bring a computer to the event and upload a program (which is complete BS), then try adding a visual feedback (LED display or something) and then making it so you can use a button to change the setting/distance.

I would highly recommend this approach. It takes out all of the "what if" possibilities that come with relying on a laptop to upload code and it wasn't too difficult to achieve.

windu34 wrote:

Bazinga+ wrote:

samlan16 wrote:Today, we got a lovely state-specific rule that says programming from a computer is considered remote control and will result in participation points only. While we are waiting for clarification about what this actually means, I am prepping for the worst case scenario that this applies to microcontrollers on the car as well.

For those of you not using a microcontroller, would you recommend a wingnut braking system, and is it equally reliable as in other events such as Scrambler? I remember doing something like that for Battery Buggy but did not believe it was that great.

It might just mean controlling it during the run, but in case you arent allowed to bring a computer to the event and upload a program (which is complete BS), then try adding a visual feedback (LED display or something) and then making it so you can use a button to change the setting/distance.

I would highly recommend this approach. It takes out all of the "what if" possibilities that come with relying on a laptop to upload code and it wasn't too difficult to achieve.

Only issue I have is that you cant fine tune the values after your first run.

Sure you can. Put on some sort of input device that the Arduino reads that can "trim" the device. You could use a series of buttons to key in a "trim" value, or add a potentiometer and read its analog value and correspond that to some sort of "trim" or "fine-tune" value.

andrewwski wrote:Sure you can. Put on some sort of input device that the Arduino reads that can "trim" the device. You could use a series of buttons to key in a "trim" value, or add a potentiometer and read its analog value and correspond that to some sort of "trim" or "fine-tune" value.

Yes that's definitely possible, but the time needed to implament that would be better spent getting the car to go faster (since time is worth so much this year).
Not to mention you are allowed to start the car anywhere behind the starting line as long as its not more than 1 meter behind. So Instead of changing the program you can simply move the car further back/forward.