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New Fairphone Bottom Module with an appropriate case

design
usb
case
bottommodule
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#1

Hello,
I’ve designed a new bottom module/PCB for the Fairphone 2. The new bottom module supports an USB type-C connector. Be aware that it doesn’t make your phone charge faster, because it doesn’t support USB-C power delivery. Also the transfer speeds will be the same, but USB-C is stronger and more durable than Micro USB. And it’s also reversable, so what do you think. Do you like my project. This time I don’t need help from Fairphone.
The First picture is the original motherboard and the second picture is my design.



New Fairphone Bottom module with USB-C port
#2

Cool thing! Do you have a working prototype? (E.g. built into a FP2?)


#3

Would it be possible to ship this with just the PCB and everything that is glued on it + a cover that users can open and close themselves, so they can reuse the loudspeaker and vibration motor of their broken bottom module (as those two components rarely break)?


#4

I plan to produce some PCBs form a PCB prototype manufacturer and solder the components by hand and test it in my own FP2


#5

Also, because I designed it my own I can improve the design to prevent the PCB from bending, which kills most bottom modules. When they bend the microphone usually no longer works


#6

Do you plan on modifying the other components (vibration motor, speaker, microphone) or add another (?) ?


#7

WOW, just wow!
I just hope, that the guys at Fairphone can and will add some support for your projects.


#8

No, for now I will have to take the speaker and the vib. from a dead module and reuse them. The microphone will be a new one. But I added a filter for the differential pair and I also added a reset fuse. Maybe Fairphone will cooparete this time, if I can show a working prototype. This shouldn’t be too hard, because I can handsolder everything and the PCB is cheap to produce, because it’s only a 2 layer PCB.


#9

Not just that. You cannot use microUSB cables anymore, but you can use USB-C cables.

For example, there is a FLIR camera you can buy which has one of three connectors: lightning, USB-C, and microUSB (example). I expect my next devices to contain USB-C. So right now I’m in dubio about which one to get. Because I don’t expect the microUSB one to last long. A higher quality, portable, WLAN-only (with KRACK fix?) costs almost double the price.


#10

Very nice and surely highly demanded by the users.

Good that you mention all of this, but generally imho one who specifically requests USB-C should know why he/she wants it. For us FP2 users it’s just a different connector (mechanically more or less stable compared to µUSB). Still it’s a smd type with small solder points. One with raw motor activities will sure manage to break it after some time too. But complaints may not come up then as there is nothing newer/more advanced available atm. There are still adaptors/cables available µUSB<->USB-C as without soldering & utilizing the full USB-C circuitry onboard there is nothing more such as quick charge, high-speed data transfer etc. available. This again seem to be very little known facts with a high potential for complaints (at some point), let alone some fried devices when users purchase the (cheapest) USB-C cable available.

I think the best way to keep it alive for long time is to adjust ones force when dis-/connecting or again use a magnetic connector, not dropping the handset when connected etc. The internal part holding the contacting pins remains of plastic.

I never had troubles with any type of soldered socket and broken joints. I am unsure if this is only due to my qualification regularly seeing devices from the inside.

…or as I mentioned above use adaptors or magnetic cables with interchangeable tip such as those. For us FP2 users there will not be a functional difference anyway.


#11

I use USB-C onboard, which uses through holes for additional durability


#12

Very cool! I was wondering just a few days ago if it was feasible to make an USB-C bottom module… and you did it! Great work, keep us updated with the testing!:grinning:


#13

This is truly a great project!
I’d instantly take one (or maybe more) of your modules once they are in stable working condition. The timing couldn’t be better, since my current bottom module is acting up again and the primary microphone seems to either have an internal electrical issue or the module itself doesn’t properly get connection, which leads to a extremely glitched microphone that either doesn’t work or give the person on the other side an unexpected scare of sudden loud static. I have to apply pressure to a certain part at the bottom cover of the phone for the microphone to work.

I’d also volunteer to help you with any beta testing for stability feedback and such, if yo require so!


#14

The speaker and the vibration Motor aren´t soldered to the PCB, so it is easy to reuse them. For a new bottom Module it is great to have the new standard USB port is a great thing. For me the new microphone is the best idea, cause the old one is not only the weakest part of the phone, it overdrives very fast. It is not doable to take a video of a concert for example, cause the sound is so poor.
Now my question: Is it possible to implement a microphone diversity, where in case of oversteer it switches to a secondary microphone which is less sensitive?


#15

This would be hard, but not impossible. But the better solution is to use a better microphone from the beginning.
By the way: Now that you have your microphone desoldered, you can try a different mic. Just pick one that supports the 3.76x2.95mm formfactor


#16

That would be easy if I could identify the old one and take a look into the datasheet
take a look here:


#17

Doesn’t video recording normally use the mic in the camera module, rather than the one in the bottom module?
Also: You’ll probably get better results with a small external mic than with anything built in.


#18
  1. I believe you mean the top module, not the camera module.
  2. Afaik both mics are used to achieve stereo sound.

#19

I do not know which Mic it uses. I assume that the mic in top module is for noise cancelling during calls. I did not find another mic, so I think the FP only have two of them in total.
I tried to use an external mic, connected to the headphone jack, but the FP does not switch to it on video recording.


#20

I took a lok at different datasheets and the pinout seems to be always the same