At MacroFab we have a large industrial air compressor that provides compressed air to our pick and place and various machines. I want to monitor the compressors pressure and run time to help influence the maintenance schedule for it.
Stephen and I talked about the Compressor IoT project on the following Podcasts: MEP EP#68, MEP EP#70, and MEP EP#74.
Working on this fan controller for my Jeep. All the files are on github. Uses a 4×40 character VFD. Has an onboard E-compass module that will show inclination and direction. Part number is FXOS8700CQR1.
I am still working on the Gameboy VGA driver. You can see the code and hardware working on the BenHeck Show. I have to get some other projects done before I can finish the Gameboy :)
Parts, PCBs, and Stencils arrived earlier this week so I put together the three prototypes for REV4. Above is pre reflow.
Directly after reflow.
Magnified picture of the board. Turned out great. FTDI chip flashes and Propeller programs over USB. The new MAX11613 ADC works as well. I will be posting the driver code for that shortly.
Micro SD Card Slot changed. Old one was Molex MFG# 502570-0893. New part is 4UCON MFG# 15882.
Tact Switch changed to more low profile switch.
ADC switched from AD7999YRJZ-1500RL7 to MAX11613EUA+. Slower ADC but increase from 8bit to 12bit resolution.
Changed Voltage Regulator from TS2937CW33 to NCP1117LPST33T3G.
Added 10uF Electrolytic Cap to 3.3V rail.
Crystal changed to low profile ABMM-6.000MHZ-B2-T.
Added voltage divider to switch to USB power if external power falls near cutoff for regulator.
Render of the PCB from OSHPark.
Top stencil pattern. The through hole pads on the micro USB connector are going to be soldered with the “Paste In Hole” method. I have not tried this yet but if it works I will be able to cut out an entire operation during production of the boards.
Finished the next revision of the Propeller Development Stick REDUX. The power switching has been changed to fix the flakiness of the past revision. I switched the TPS2115 to a TPS2113. This seems to have fixed the weird power switching issues. The layout has change completely. SD card slot is on the top side of the board and the power circuity and ADC are on the bottom now.
Finished drawing the case last night for 3D printing. Used SketchUp to draw it as its free. Still searching for that perfect 3D modeling program. SketchUp is an ok piece of software. Compared to AutoDesk 123D V9 it lacks some features but the newer 123D Design (they changed the name slightly) its pretty lame.
Testing the standby current draw for the OctoPROBER. It uses a soft power switch and a real time clock which draws power when the device is turned “off”. Fortunately the power consumed is very small. At a battery voltage around 4V the standby current is under 20uA. With a 2000mAh battery we have a standby lifetime of 100000 hours or over 11 years! Don’t really have to worry about the OctoPROBER loosing its clock time anytime soon.
Above is the REV 1 of the OctoPROBER. This revision fixed allot of the issues I had with programming the propeller and the propeller resetting when the USB plug was plugged in. To fix the USB resetting the propeller when being plugged in I disconnected the reset line off the FT230X (USB chip) from the reset signal on the propeller. This breaks being able to program the propeller as it needs to upload code directly after start up. To fix this problem the code has a menu option that will reset the propeller if it sees the USB reset line so the user can control if the USB resets the propeller or not.
To enable ease of first time programing or encase the firmware gets borked there is a switch that manually connects the FT230X reset signal to the propeller reset signal.
Rev 2 of the OctoPROBER I decided to do away with the MAX31855 chips. They are very expensive ($5 a piece) and not very accurate (+-2C). Instead I am using 2 MCP3424 18-bit ADCs to do the thermocouple readings. To perform cold junction readings I am using 8 AT30TSE752 board temperature sensors. This should provide +-0.5C accuracy and the ability to use any thermocouple type.
