I recently purchased 3 BrickPis for my classroom (2 have arrived thus far). I purchased the kit that includes the ready to go SD cards. I built the Pis following the instructions online and was able to connect 1 BrickPi to the HDMI cable and projector in my classroom once. This BrickPi no longer connects to any monitor I hook it up to and the other BrickPi I have never got a monitor to sense.
I have read through the forums and found advice given to other people about connecting the BrickPi first and then powering it up. I am using the BrickPi microusb charger and the lights are turned on. Any next steps would be extremely helpful as my students and I are dying to use these!
The complete brickpi package is 2 boards (raspberry pi and dexter brickpi) The micro USB charger will only supply enough power to run the Raspberry Pi but not enough to run the BrickPi. If you have the brickpi connected to the Raspberry pi without a power source for the brickpi board then it is possible that the brickpi is drawing too much power for the raspberry pi to run properly. The brick pi should have come with a battery case that houses 8 x AA batteries. If you connect the 8 x AA batteries to the brickpi then it might work for you.
If you have the 8 x AA batteries connected to brickpi it will have enough power to also run the raspberry pi. i.e the raspyberry pi won’t be able to power the brickpi but the brickpi will be able to power the raspberry pi
The HDMI connection should be made prior to powering up the Raspberry Pi. Some monitors (and probably some projectors) may also need to be powered on prior to powering up the Raspberry Pi. Make sure you have a good solid connection (cable isn’t half-way inserted), and maybe try a different HDMI cable.
As long as the Raspberry Pi’s 5v USB power supply is adequate, the BrickPi will run. If it’s a BrickPi+, don’t try running motors when you don’t have batteries connected, and note than some sensors might not work as expected. If it’s a BrickPi3, the motors will automatically be disabled if there isn’t adequate battery voltage, and all the sensors will work normally. The BrickPi3, even with sensors, uses minimal power from the 5v rail (an order of magnitude less than a Raspberry Pi with WiFi).
