Electrical – SIM900a Modem IMEI 0, Help with TX RX pins

I have this strand of LEDs/Controllers and I've made it work with the LPD6803-RGB-Pixels library.

To connect the strip correctly:

• Di (Blue Wire) = VCC -> Connect pin: Vin on Arduino.
• Ci (Green Wire) = Data -> Connect to pin: 2 on Arduino.
• St (Red Wire) = Clock -> Connect to pin: 3 on Arduino.
• Li (Black Wire) = GND -> Connect to pin: GND on Arduino.

Once the Arduino is programmed, unplug USB cable, and only use the 12V supply.

Hope this helps.

I think you're killing the tantalum capacitor across the input. In fact, it looks like it's bulged up in your photo.

Although the capacitor may be rated at 16V (I don't actually see a rating anywhere, but I'm inferring it from the size and input voltage spec) seasoned engineers will never use tantalum capacitors in this sort of situation. The input current needs to be limited by several ohms and/or the rated voltage should be something like three times the operating voltage. Your wall wart can probably supply several amperes.

Years ago, this information was anecdotal, but today you can find it buried deep within the manuals for such parts. They bury it, because it means you very seldom should use tantalum capacitors, and almost never across power supply rails unless the current is limited to much less than an ampere.

Many have been burned by this (perhaps literally). Often failures take place long after product has been shipped, and can cause localized charring, meaning (if your standards are high, as in aerospace or medical) the entire board must be scrapped.