Category: Server

[Mini-Server] UPS Redesign

My portable USB phone charger’s LCD screen broke today, so i decided to tear it apart and use its 11,200 mAh battery for the server UPS. I also recently built a 3D printer, so I designed a case to hold  the components to my budget Ebay UPS.

I decided to refine the schematic the same for the USB UPS, because the boost converter was prone to dropping out early, and therefore the battery was never 100% usable.

The new schematic uses a TP4056 1A Lithium Ion charger with a DW01 Battery protection IC and the MT3608 DC-DC boost converter (capable of boosting a voltage as low as 2V up to 5V with 2A of output current). 3A rectifier diodes and a large capacitor are used to smooth the transition between mains sourced 5V power and battery power.

The whole circuit can be assembled for less than $8. (The high quality super capacitor being the most expensive part)

In testing, the Mini-Sever can now run for just shy of 4 hours off of mains power.

[Mini-Server] UPS

I built a UPS using a an EBay sourced boost converter and lithium ion charge controller. I used a lithium ion battery I salvaged out of an old bluetooth speaker. I mounted it all to a sheet of aluminum. Total cost: $3

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I used a 3.3v signal from the power supply to tell the pi if it lost AC power. I modified my software to E-Mail me and shutdown the pi if the battery got too low.

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In testing the UPS, I uncovered that at a certain point, about half charge on the battery, the voltage dips and the boost converter drops-out triggering a reset on the pi. I only end up getting around 20 minutes of battery life with the 750 mAh battery, which is adequate for most power loss events.

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[Mini-Server] Server Circuitry

I secured the LCD in place with screws and made a 3.3v to 5v 2N3904 level shifter for the I2C communications between the screen and the pi. The switch is wired and works as an interrupt in the python code. I also used one of the pi’s pwm outputs to pulse the button LED, so there is a “breathing” effect when there is a notification.

I need to cleanup the code and add a menu system so I can control a few programs. I also need to clean up that circuitry!

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[Mini-Server] Case mods

The case has a small fan that can be controlled with pwm, and a LED/pushbutton. No screen!

I had a $3 Chinese I2C 16×2 LCD display laying around. So, I got to work with the dremel and file and now the case has a LCD.

I need to have the faceplate machined and refinished. I modeled the cutout in Solidworks and sent it out to be cut. Luckily, I know someone who can do it for free.

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[Mini-Server] New project

I bought a Raspberry Pi 2 a while back…. It promised more RAM and a faster clock speed than the B+ model it was replacing.

I could finally run a low power Minecraft Server! I downloaded Raspbian and put it on a class 10 microSD and was hoping to be mine-crafting in minutes.

I got everything setup and attempted to connect from my gaming machine. Loading. Loading.. Loading… Loading…. LOADING

Well it did work but the frame rate was horrible. I tried tips on configuration settings I found on the minecraft/pi forums, but nothing made it any better.

So I was out $30…., Or was I?

I then hatched the brilliant idea of making a website on the pi to host my projects. I got everything configured and a basic version of my site setup. Then it ended up sitting in the corner plugged in, at times narrowly avoiding being mauled and disfigured by the vacuum cleaner.

I set out to make a proper case with a screen and UPS.

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