Three boards arrived from OSH Park today. First 4-Layer board I have ordered from them. Quality is pretty good. Silkscreen is a bit weak but that is probably due to me running the weight of the text to thin.
Internal two layers are GND and 3.3V. Outside two layers are signals.
Close up of the kickass OctoPROBER logo.
Character display mounts on the back of the PCB. This way the PCB can be mounted to the front of the case without silly long button caps on the tact switches.
The Pinheck Pinball System uses a PIC32MX795F512L-80I/PT mcu. It is a 32bit mcu running at 80MHz with 512KB of program space. Plenty fast enough for pinball. The only reasonable package it comes in however is TQ-100 package which has a pitch width of 0.5mm. This pushes the limit of the vision system of the DP2600-2 but I managed to get the system dialed in to make the placement.
The PIC32MX795F512L-80I/PT is a tray part so the machine does not pick the part up from a feeder. Instead you line up all the chips in a row and the machine knows where to look for it. Uses the vision system to find and locate the part.
After picking up the chip the machine takes it over to the “Uplook” camera. Here is can make sure the part is oriented correctly and lined up.
The machine then moves on over to the part location on the PCB and places the part. In the image you can see the dark areas between the shiny leads of the PIC32. The dark areas are the solder mask showing through which means the part was placed correctly and straight.
The Pinheck Pinball System is currently being tested in America’s Most Haunted. Once it gets a good bill of health we will move it to getting actual production boards made.
Finished REV 0 of OctoPROBER last night. I added a MCP3021 which is a I2C 10bit ADC with one analog channel. It will be used to monitor the battery voltage and indicate when the lithium battery is close to being dead.
Schematic is a bit of a mess but I will be cleaning it up.
Files are on GitHub. Will start programming the hardware test software this weekend for the propeller.
An update on the OctoPROBER layout. I added a Real Time Clock (RTC part # DS1340Z-33+) to the I2C buss. Temperature recordings can be logged with an accurate time stamp.
To keep the time when the unit is off it pulls power directly from the lithium battery. When the OctoPROBER is powered on it pulls power from the 3.3V power rail.
Speaking of the battery the OctoPROBER’s main power source is a 18650 lithium cell. Power draw is around 200mA so a 2600mA battery will last around 13 hours. The RTC in standby mode pulls 125uA max which gives it a max standby time of 866 days. That should be plenty for most use cases.
Late Edit.//
Fixed some more traces. Just need to work on cleaning up the silkscreen then it is off to the fab house!
This has been an idea I have been kicking around for awhile. The OctoPROBER is a 8 channel, K-type thermocouple temperature logger. It has a micro SD card slot for logging data remotely. The USB connection can send log data directly to the PC.
Power is supplied via internal lithium 18650 3.7V cell and is charged over USB. The BQ24075RGTT is used to manage the charging of the lithium battery by using the outputs of the FT230X USB chip. I will cover this in more detail when I can verify my idea will work.
To prevent corruption of the SD card a soft power circuit is employed. A single optocoupled output is given to allow control of an external circuit.
Just finished testing the REV 4 prototype. Flashed the Propeller and PIC32 successfully multiple times. Test software verifies that the hardware is working. I pushed the last fixes to GitHub that will make up the REV 5 board. Looking at selling the boards around the $400 mark fully assembled and ready to go with sample code.
The Parallax Propeller MCU runs in 3 different flavors. A DIP-40 package (P8X32A-D40), a LQFP-44 package (P8X32A-Q44), and a QFN-44 package (P8X32A-M44). This appnote covers the two SMD packages; LQFP-44 and QFN-44.
The schematic is fairly simple as its just to show a typical layout of for the Propeller. The part number for the crystal is a 6MHz which will run the Propeller at 96MHz. It is a common HC-49/US package so the standard 5MHz type crystal can be used with this layout.
I made a special footprint that can use both the P8X32A-Q44 and P8X32A-M44. This way a part shortage on either package won’t hurt production. I made sure to leave plenty of room around the chip and supporting circuitry for easy fanout of the I/O. Just make sure to route away from the X0 and X1 crystal I/O to reduce EMF.
Files can be found on the GitHub repository and the footprint itself can be found in the my Eagle Library.