3pi LCD problem, DC mootr 5:1 & QTR-8RC Reflectance Sensors

Hi guys,

3 cuestions about my 3pi.

1.- My 3pi LCD doesn’t work.

The 3pi buzz at the start, but LCD not. (I´ve just adjust the potenciometer, from min to max…)

How can I test the LCD?
The 3pi can work without the LCD?
With the Atmel Studio 6.2, … Can I Check the LCD or show in the pc the LCD texts?

2.- I´ve bought a apir of DC motors 5:1

The original 3pi have 2 DC motors 30:1.

Is it able to change de DC motors 30:1 by 5:1 reduction? It’s to try more speed
In the program, are there any change to do?

3.- I’ve bought too QTR-8RC Reflectance Sensors Array.

How many sensors more can I use with the 3pi?
Is it easy to conect and programm?
Have you got any exmple o squem?

Best regards


The 3pi can still function without the LCD. If you already tried adjusting the potentiometer and the LCD still didn’t display anything (and your code is printing something onto the screen), it is possible that the LCD is damaged. There is not a way to test the LCD through the PC. Could you post pictures of your 3pi powered on with the contrast set to the highest and lowest settings? Did you ever connect the LCD onto the 3pi backwards?

It is possible to swap out the 30:1 gearmotors with 5:1 gearmotors; however, I am not sure how well the 3pi would work. The additional speed might make it difficult to control the 3pi. Also, the torque might be too low for certain applications depending on which version of the 5:1 motor you purchased. The 30:1 micro metal gearmotors on the 3pi are the low-power versions. I do not recommend trying any of the high-power versions of our micro metal gearmotors since the motor driver on the 3pi might have problems driving them.

The 3pi does not have many free IO pins. It is also not clear if you are planning to use the integrated QTR-RC reflectance sensors that are on the 3pi in conjunction with the QTR-8RC sensor array. You can see which IO pins are used on the 3pi in the “Pin Assignment Tables” section of the 3pi user’s guide. If you post a diagram of how you intend to connect the sensor array, I would be happy to take a look at it.

By the way, since you have selected a sensor array and motors for your robot, you might consider building your own robot using one of our Orangutan robot controllers, which have integrated motor drivers and LCDs.

- Jeremy