First of all, you will need to make sure that the cable you are using to connect Micro:bit with the computer is designed to be a data transfer cable (i.e. it has all of the wires inside it populated) rather than just being a charging cable. Some charging cables that come with mobile phones and other portable devices only have the power wires fitted - which means that your micro:bit will power up when plugged into the USB of your computer, but you will not be able to drag and drop code on to it.

When the micro:bit is powered from USB, the yellow system LED on the back will light.

Also, if one USB port does not work, you may try another USB port on your computer, sometimes the problem gets fixed this way.

Micro:bit can only carry one .hex file at a time. If you move a new .hex file, it will replace the previous one. You can’t drag and drop more than one hex file at once onto your micro:bit. If you try to drag and drop a second hex file onto your micro:bit before the first file has finished downloading, then the second file may fail in different ways.

If the micro:bit runs out of resources or detects a fault, it enters a 'panic' routine which displays a sad face on the micro:bit screen followed by a number (for example, 020). In all cases, pressing the reset button on the back of the micro:bit will restart the program, which clears out the RAM memory and starts again.

You can consult this page for the details of any specific error code.

To reset your micro:bit to run the default program that came with it (called the Out Of Box Experience), download and flash this .hex file via USB.

If you are unsure on how to do this, follow our article on How to transfer code onto the micro:bit via USB.

The DHT11/DHT22 Sensor shows some problems if reading are taken in quick successions. So, it is a better approach to add "Pause (ms) ____" Block after each Read Humidity/Temperature blocks. Pausing for at least 2000 ms (2 seconds) is the optimum solution.

Sometimes, if the displayable text is long, it can get fragmented and give wrong outputs. You may add additional blocks like "Insert New Line", which may solve such problems. Also, do not forget to round up the temperature, or else it will show a long output, for example, like 71.2342376..., instead of 71.

You may post your question on the Discussion Board, or you may send us an email, or you may post your question on the padlet page of the Episode.

You may also go to the official troubleshooting site for Micro:bit.

You can attach the sensors and other devices to the ports like P0, P1, P2, etc., of the Grove Shield. But, one thing to remember, the OLED screen needs to be attached to the I2C port.

You should connect the red alligator clip to the 3V port and the black aligator clip to the GND port.

You need to be careful while attaching a charger to the Micro:bit or Grove Shield. Because, the circuit can tolerate upto 6V, and the output from a USB port is usually 5V, which is converted to 3.3 Volt within the Micro:bit device. Also, we may attach batteries or Power banks, which have output close to 3V. But there are some phone charger which can give output above 6V volt, which may irreparably damage the Micro:bit device. So, you should avoid using such powerful charger to the Micro:bit device.

It is advisable to connect one Micro:bit with one USB port, as connecting two Micro:bit devices with the same USB port using USB splitter sometimes may cause unwanted problems.