• ### New product: VL6180X Time-of-Flight Distance Sensor Carrier

- 14 February 2018

Hello,

I'm glad to hear that you like the parts and our prices!

It also sounds impossible to me, and we don't have detailed information about how the ST devices work, but they do specifically talk about measuring the time of flight, and datasheets for similar parts like the ISL29501 give more details about how you can use analog signal processing to determine an absolute flight time. Of course the electronics can't do much in a few picoseconds, but signal rise times of 10 ns/V and millivolt sensitivity are normal, which gets you to that timescale. Building an interferometer in a chip and sweeping the frequency of a laser diode sounds a lot harder.

By the way, the light has to go there and back, so you can double your times, which helps a bit.

-Paul

• ### How to make a Balboa robot balance, part 4: a balancing algorithm

- 12 December 2017

Hello,

Part 5 of this series discusses driving around. Please also see the comments for some more suggestions.

-Paul

• ### How to make a Balboa robot balance, part 5: popping up and driving around

- 5 December 2017

Hello,

I don't have any immediate plans to do more tutorials. But if you have made it this far with your Balboa, you should be ready to explore these ideas on your own! Any of these ideas would be taking it further than what I have done, so I would be interested to hear what you try and comment on it; maybe you could post your progress to our forum. For navigation, you might be interested in my dead reckoning robot from a few years ago; you could probably use the same basic approach to do more precise navigation with Balboa. There are a ton of tutorials available for IR remote control; since the Balboa doesn't have any built-in support for this, just look for any Arduino remote control project. Here's an example from our Zumo library using the built-in sensors on the Zumo, which are also available as discrete modules (though there are other sensors that are more appropriate for remote control applications).

-Paul

• ### How to make a Balboa robot balance, part 2: inertial sensors

- 27 March 2017

That's a reasonable idea. I have never actually seen it fail to initialize the sensor. If it did occasionally fail, I might change that line as you suggested, but only after looking into the source of the problem and determining that there is nothing I can do about it. Our examples are not intended to be robust against communication failure, so if you need something more robust, you might also want to look into re-initializing the sensor if it fails during loop() and consider enabling the AVR's watchdog timer.

• ### Building a Raspberry Pi robot with the A-Star 32U4 Robot Controller

- 4 October 2016

Thanks for the comment! I have updated the command as you suggested.

-Paul

• ### Paul's dead reckoning robot

- 19 August 2015

For anyone interested in building a robot like this, our new A-Star 32U4 robot controller includes most of the electronics shown here, on a single PCB. So if you use that, you can skip the breadboard and directly wire your batteries, motors, and sensors to the controller.

• ### Paul's dead reckoning robot

- 20 July 2015

I have not made a wiring diagram (need to learn Fritzing!), but I still have the robot, so if there are any connections that are not clear in my post, I would be happy to check them for you.

• ### Math on the Pololu website!

- 27 June 2014

Ben wanted me to post the details of the Gaussian integral, so here we go.

It's simpler to think about the full integral from -oo to +oo. Let's give that a name:

lambda = int_-oo^oo e^(-x^2) dx.

Then, instead of trying to compute lambda, we work on lambda^2:

lambda^2 = ( int_-oo^oo e^(-x^2) dx )^2 = int_-oo^oo int_-oo^oo e^(-x^2) e^(-y^2) dx dy.

We note that e^(-x^2) e^(-y^2) = e^(-(x^2+y^2)) and rewrite in polar coordinates:

lambda^2 = int_0^oo e^(-r^2) 2pi r \ dr.

Luckily, that integral is easy, since d / (dr) pi e^(-r^2) = - 2 pi r \ e^(-r^2):

lambda^2 = - [ pi e^(-r^2) ]_0^oo = pi;

lambda = sqrt(pi).

Finally, since the Gaussian is an even function, our desired integral is just half of that value:

int_0^oo e^(-x^2) dx = sqrt pi / 2.

• ### Pocket-sized USB charger adapter

- 6 March 2014

Thanks for the nice feedback, and please let us know when you post more projects!

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