[HeRos] After the storm, the sun !

Today was a trying day nevertheless efficient. The reason was that we have solved two problems. The first one referred to my post of yesterday and the second one arrived just after we solved the first problem.

The first problem was that two HeRos were not able to transmit data over the UART to the Pololu. The transistor was probably damaged. We still were able to oscillate but at low frequency since the up time was very long. An other strange fact was on the voltage of the serial RX transmission. When the HeRos was connected to an USB port of the computer we had 3.3V contrary to with a Pololu where we found 2V. Alexis solved the problem by adding a pull-up to the line. Now, we set the pin as open drain and we only drive the low level. The HeRos are able to use the Pololu again.
However, one HeRos was a little bit more damaged. We were not able to drive the RX pin and the maximal voltage was 1.2V. Maybe we will look next week with Alexis in order to bring him back. By the way, we still have no idea how did the Pololu damage our HeRos.

The second problem was easier to solve and a kind of funny (when we understand it, of course). On one Pololu, the camera didn’t work any more except sometimes during a global shot. We concluded after debugging our code that it was good, on top of that the same code was working on other HeRos. We pointed out that the camera only worked when the red led 3 was lighting. After looking on the schema, we saw that the pin is between the Uart3_Rx and Uart3_CTS and we might have a contact.

With all the problems, we are delayed on the external modules but we are still good. I took pictures tonight with Charles, have fun 🙂


Global Shot Demonstration

HeRos touched by a global shot

Direct Shot Demonstration

HeRos touched by a direct shot


HeRos in darkness

HeRos in darkness


Eric Masseran


1 comment to [HeRos] After the storm, the sun !