Summer 2017 Week 3

It’s Thor again!

Last time I posted, I had edited our PCB to include an ATMEGA chip and a new ethernet port for an easier connection to the keypad. My idea of how big the ethernet cable is compared to the board was off, so the design was not good.

Ethernet too big

I had the ethernet port facing down the PCB (toward the right in the picture). This would have caused a problem with the cable and the piezo buzzer, so Owen redesigned the PCB. Owen's redesigned PCB

This is the picture from OSH Park showing what the new PCB would look like after manufacturing. The ethernet port is now turned to the right to not interfere with any components and there are 5 neopixels in a row in the middle of the board. The code to implement the strip is just a simple upgrade to the code for the one light that is on the board now. In the bottom left corner is the piezo buzzer. We are switching to a surface mount buzzer. In the bottom right corner are a few holes labeled “ISP1”. These will be used to program the ATMEGA chip on the board to avoid any problems programming it using the Pi.

I now have 11 days left of employment on the CATS device for the summer. Hopefully we can get the PCBs in and then it will be crunch time when I start soldering and assembling.

Until next time!

Summer 2017 Week 2

This is Thor again, back with some more summer news! Since the last post, it has been a little slow because of waiting for the order to arrive so I can assemble the new boards. Last week I was able to have the Arduino control the successful login sound and light. I have now coded an unsuccessful sound and light. All it does it beep and blink red, but the Arduino is able to read in a string sent serially by the Pi. If the Arduino reads in “login”, then the successful code runs and if it reads in “error”, the other code runs. This way, we can have different sounds and lights set up to execute at different times when certain actions occur. The Pi can sent string serially and then continue on with the code while the Arduino takes care of the light and sound. This will prevent interruptions in the Pi code so the keypad can function at a fast pace. On the new PCBs, we have the serial connection between the TX (transfer) and RX (receive) pins on the Pi and Arduino. They will have to be tested when we assemble them because I was only testing the connection over a USB cable. Only the RX from the Arduino and the TX from the Pi are going to be connected, so that the Pi can send strings to the Arduino. We do not need to send anything back to the Pi. The Arduino also runs on 5V logic while the Pi runs on 3.3V logic. The Arduino can handle and understand the 3.3V signals coming in from the Pi but vice versa would need a voltage divider. To simplify the hardware, we are not going to have the Pi receive anything back from the Arduino for now.

Once the shipment of parts arrives, we can assemble them and hopefully our devices work the way we intended so we can begin installing them on machines if time permits.

Until next time!