Month: November 2021

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CUMonitor Consumer Release

Development of the CUMonitor hardware is progressing and the first boards acceptable for consumer release have arrives and are going thru soak testing.

CUMonitor PCB changes

The major changes have been to add the facility to power the board through a micro USB connector adding onboard voltage regulation of the 3.3v.  The new A to D circuits can run without the the addition of a burden resistor so these have been removed. This means that the CUMonitor consumer PCB assumes that the 30A 1V current clamps will be used. But this should be OK form most household use cases. The surface mount spaces for the burden resistor have been left in case 100A clamps are required. There was a missing resistor on the previous board that is also fixed.

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CU Monitor PCB Upgrades

The CU Monitor PCB upgrade has involved quite a few changes. Moving to the ESP32S2 processor has meant completely revamping  the build to use  the newer and faster processor. Aside from doing away with the with the ADS1115 chip and reading the A to D values across the I2C bus the board has simplified in a number of other ways.

I’m pleased with the upgrade process even though the PCB board will have to be recreated. The  porting meant using new libraries and did away with the I2C bus. There is lot more space on the chip for expansion and the number of samples  per second has risen to more than 9000 from the few hundreds we had with the old design. The current run of PCB’s have burden resistors that are now redundant and one missing resistor from channel 2. But otherwise appear to work great. I’m soak testing them now before ordering some production quality boards and to see if there are any “undocumented software features” in the new libraries.

One change to go in is adjusting the recess of the jack plug sockets these need to be less as when the jack plugs are inserted thru the case they experience an ejection force because the case pushes the jack plugs away from the PCB. Also I need to add pylon holes to allow rapid alignment when the PCB is inserted into the case