Introduction: How to Recycle Android Phones for BOINC or Folding Rig Without Using Batteries
I AM IN NOT IN ANYWAY RESPONSIBLE FOR ANY DAMAGE DONE TO YOUR HARDWARE BY FOLLOWING THIS GUIDE.
This guide is more effective for BOINC users (personal choice / reasons), it can also be used for FOLDING
Since I do not have too much time, I will try to make this tutorial short, but will add info if more people request it.
Step 1: Hardware
The idea is to have a
regulated power supply with enough Amps to feed as many octo-core android you can get your hands on
My setup is based on a TDK-Lambda HWS-150A-3/A 3.96 V/DC 30 A which I bought for under 100 euros. This open frame power supply gives 30A at 3.3V +/- 20%, which means 3.96V max, above the 3.8V requested by the “battery”
Initially I used another TDK Lambda with 12V & 12.5A (much cheaper version LS150-12) together with a cheap buck converter which reduce the voltage to 3.8V.
For ideal results, all batteries used in the smartphones should have a nearly identical voltage which should be around the 3.8V. For almost an year I’ve been using 2 octo core Landvo smartphones with USB 5V by using the “salvaged” battery circuit. For the other Allview androids this method is not working, although at 5V I was getting messages of … over current, since I did not “salvaged” the battery circuit.
The most important/difficult piece of the hadware is the USB hub. A friend of mine had to 3D print it and solder all the circuitry. Basically it feeds the desired non-standard voltage (in my case 3.8V) but it has the option to “fast charge” at 5V (which I did not test, since if you need 5V there are a bunch of options to buy from)
The 3D schematics he will add them a bit later and I’ll update the tutorial here
Since no batteries are involved, on the back of the phones I soldered the “red” to the plus and “black” to the minus. The other 1, 2 or 3 middle pins I found them irrelevant, you can search on the internet
Step 2: Software
I only used official
BOINC, and I guess it will be better to enable also play store updates, unless the phones are not limited by RAM
I prefer to run WCG since this is basically a Badge Rig, although the 256MB RAM limitations depends on the project, and sometimes I guess 7 Cores take up something like 400MB RAM
So basically I have been running this for the last two weeks or so and I am getting around 97%
CPU Time / Elapsed Time (hours) in WCG :)
Step 3: Control & Tuning
I am using team viewer + host installed on the phones. Although Landvo + Allview does not support full remote control, it is the only solution I could find. Please add in comments if you are using another solution.
I am running only 7 out of 8 cores, just for caution, but the SoC does not get very hot.
Right now I am running 4 octa + 1 dual on the rig, and 2 octa (Landvo) on a normal usb hub, see table below.
Step 4: Possible Improvements
I will try to switch to Samsung phones since they should be able to run team viewer with quick support.
It will also be nice if I could print a 3D battery with only the red + cable coming out in order to use the phone back cover.
10 cores phones would be nice to try when they will be more common and cheaper.
In order to reach the goal of 20 octa, I could use some wago 222-415 (5 wires) lever nuts connectors (one hub of 5 usb per wire) since the open frame power supply does not have enough place to insert the 4 hubs wires
For errors and correction please leave them in the section comments below.
Step 5: This Is for the Makers
3D printing + Soldering required
My friend did this part, so I cannot give too many details.
KiCad files attached also for soldering and to have a view of the 3D model