Ever since the Palm Pre came out I’ve been in love with it’s inductive charging upgrade. Similarly to the Powermats, the charging base acts as a device stand with it’s integrated magnets in addition to charging your device without having to plug and unplug your device every time you need to use it. Once on the charger it outputs 5.50v. It’s a bit higher than other USB chargers I’ve used.
“Induction chargers typically use an induction coil to create an alternating electromagnetic field from within a charging base station, and a second induction coil in the portable device takes power from the electromagnetic field and converts it back into electrical current to charge the battery. The two induction coils in proximity combine to form an electrical transformer.” -Wikipedia
After peeling off part of the backing you can see the coil and it’s output circuitry. You can also see the four magnets it uses to attach itself to the charging base. They do a good job of holding my heavy phone and case to the base.
After finally getting in the Touchstone base and replacement back I decided to get this working over some lunch. I was a bit uncertain at the time that the magnets would be able to hold my phone while it’s in it’s case. I also wanted to make sure that I wouldn’t experience any signal loss issues or suffer from any overheating while charging. I found the quickest way to make this work was to take the male end of a microUSB plug and wire it directly into the contacts off the inductive back. After taking apart the microUSB plug from a spare dead cable, you can use a 200 ohm resistor to short the D+ and D- pins on the plug. This allows the device to charge at a higher current, which will in turn charge a bit faster. After soldering it up I used some colored silicone to insulate the back of the plug.
In order to clean this up and make it a bit more permanent and presentable, I have get away from using the charge port and get it through the housing. Unfortunately, the back housing of my phone has a nice metal frame right where I want to mount it. There are also a few antennas I need to avoid. The induction coil is going to have to stay on the back of the case, and somehow get passed thorough the metal housing into the board. I drilled through the back of the case near the sim card holder.
It took a bit of poking and prodding but I was able to find 2 test points that when the motherboard was plugged into a USB charger had +5v showing between the points and the ground plane. No magic smoke was released!
After a bit of soldering I was able to route the positive lead out of the phone housing and is now staged for the next step- going through the housing and into the case. The metal frame of the sim card holder is attached to the ground, so I can use that to complete the circuit. On a normal USB type charge port the ground pin attaches to the ground plane which is usually where all the shields are anchored into so I feel safe doing the same.
For the next stage of the project I’ll have to use some contacts or pogo plugs embedded within some silicone to go from the inside of the phone to the contact points on the induction charger. Ben had the good idea of using some thin copper PCB protoboard to act as thin traces.
To be continued!
- Tonight @ 7pm is our #CodeMonkeys Meeting. Tonight’s topic is on Github. Here’s the plan for tonight
- Non-Members are welcome.
- Tomorrow night 9/7 – Meeting @ Republic Coffee 7pm. (As always, non-members welcome)
- Thanks to Brandon, we picked up 42 Pentium 4 computers, and a very nice SAN and Server rack.
- We’ll be working to go through the 42 Desktops so we can inventory the hardware.
- We’ll definetely need help working on the machines, we’ll let everyone know when we plan on working on them.
- The goal for the PCs is to set a few aside for group use and then possibly sell (cheaply) the rest with proceeds going to the Laser Cutter Fund.
- There is a leak by the back door, we had to pull up the carpet, we’ve got the landlord involved and currently waiting to hear back from him.
- We have some new members and a couple of pending new members. If you haven’t been to a meeting in a while, come see the new faces.
- Claudio has started a thread on the email list for those wanting RaspberryPi cases printed on the 3d printers for donations to the laser cutter fund.
- Rachel is prepping info to do a class on Stained Glass.
- We have bought a storage rack and The Artsy & Crafty among the group have begun plans for storing and sharing various arts and crafts supplies at the space.
- Ben is going to pickup the storage rack today so it should be at the space for anyone who would like to go put it together.
LAN PARTY VI: The Undiscovered Fragger
THIS SATURDAY! 8/25 – 4pm
Food: Pulled Pork – $10 person BYOB
Raspberry Pi Raffle: Drawing @ 10pm Tickets $2 each!
List of Games We’ll Most Likely Play (Feel Free to Suggest):
- Left 4 Dead 2
- Monday Night Combat ($10 – Steam)
- Super MNC (Free – Steam)
- Diablo III
- Unreal Tournament 2004 (Should be cheap)
- Microvolts (Free – FPS/Team Deathmatch http://www.microvolts.com/ - Requires free user account)
- Team Fortress 2 (Free)
What you need to bring:
- Keyboard / Mouse / Game Controller
- Headset / Headphones (please no speakers)
- Surge Protector / Power Cables / Cat 5 Cables
- Bring your own chair if you wish (nothing too large)
- Any snacks / drinks outside of food we’ll provide
- Cash for Food / Drinks / Raffle (We take PayPal too)
Age Requirement: You must be 18+ or have a parent / legal guardian with you to visit MidsouthMakers.
Just heard for Jeremy, the leader of the Memphis PHP User Group. We’ll be hosting their monthly meeting this Thursday. Their meeting topic this month is “Building Magento Extensions with Brian Wentzloff” Id love to see some people from the #CodeMonkeys come check this out. We’ll definitely be doing some PHP in the near future. Magento is a very powerful E Commerce platform that quite a few companies are using, so the presentation should be very informative.
Our very own Cliff has graciously donated a RaspberryPi for us to raffle off. We’ll be selling raffle tickets for $2 per ticket with no limit. All proceeds of the raffle will be put towards our Laser Cutter Fund which we are getting near our target goal. We’ll be drawing the winner of the Raffle at the LAN Party on August 25th. You do not have to be present to win. Please see Joe to purchase tickets any time between now and August 25th.