We have all been through “duh” moments while working while debugging our projects. There is a running thread in the forum, started by cde.

Today, while trying to create a motion sensing Pantry light, using a HC-SR505 mini PIR sensor, was the overly sensitive sensor. I was trying to power it directly from the Launchpad’s 3.5V line, but it kept retriggering and retriggering for no reason! It has a beefy 22µF and 0.1µF caps on board, but it wasn’t working.

Turns out, its because I had some common anode leds for testing, through the MSP430. Whenever the last led @ 13mA turned off, either VCC dipped or Gnd rised, causing the damn PIR sensor to trigger. The caps were useless. I wish I had a scope to see what was actually happening.

So What is the stupidest thing you ever had to troubleshoot?


Setting different addreses to two of nRF24L01’s. Took me two days to figure…

Rei Vilo

Inverse the +3.3V and Ground for an MSP430… Luckily, the MSP430 survived!


Keep getting error message in CCS saying unable to program the LP (not exactly but something very similar to that meaning). 100% sure the board is connected. Unplugged the USB and plugged in again, restarted CCS and restarted PC. Turns out I tried to program a non-existent 2553 as I moved it out from the LP to a breadboard


Switching MISO and MOSI for a SPI EEPROM, while building my PicKit3 clone. On the original schematic from the PK3 user guide they are called SDI and SDO, for both the MCU and the EEPROM. So I naturally connected SDI to the same net, and SDO to another one. But in reality SDI was the input on both sides, and SDO the output – so they should have breen swapped. It took me about 3 months to find this out 🙁

Share your frustrations in the comments below or in the forum thread.

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