Wish List - Hardware
This page details hardware features which some would like to go into future phones similar to the Neo1973.
Related pages are:
- Wishlist - Hardware - Novel Devices - openmoko will run on a large number of devices in the future, some of which may be DVD players, cameras, or convergance devices.
- Wishlist:Unlikely - Hardware that is unlikely to appear in any OpenMoko device, due to it being impossible to fabricate with near-term technology, or for other reasons.
- Wishlist:Accessories - Accessories that people would like, that connect easily to the phone - initially primarily for the Neo1973
- Wishlist:Expansion - add-ons to the phone, maybe involving hardware changes, and software and hardware protocols to implement these.
This page is rather long. Before adding a new idea, please read through this page and the above pages, to make sure your idea has not been suggested before.
AT91CAP9S500A (ARM9 + FPGA-port)
- 20 March 2007 Green supercomputer is 'go' in Scotland Quote: "...A supercomputer 10 times more energy efficient and up to 300 times faster than its traditional equivalents..."
Take a look at this microcontroller, that integrates an ARM9 microcontroller and a dedicated FPGA port: AT91CAP9S500A. It has "only" a max. clock at 200MHz, but can use a FPGA for hardware acceleration, that could be used for video (de)compression, aacPlus v2/HE-AAC v2 sound (de)compression and many other things. HE-AAC v2 is better than MP3.
- AT91CAP9S500A Quote: "...The AT91CAP9S500A is built around a 12-layer bus matrix, allowing a maximum internal bandwidth of twelve 32-bit buses. Its distributed DMA architecture enables multiple data transfers to take place between the processor, memories and peripherals with minimal processor overhead...".
- GNU-Based Software Development on AT91SAM Microcontrollers
- Maybe this is a good tool?: BYU JHDL, Open Source FPGA CAD Tools
- 02/05/2007, FPGA tool bottleneck stalls HPC Quote: "...Current FPGA synthesis, placement and routing tools are written for hardware designers, not software programmers simply trying to accelerate an algorithm..."
- http://sourceforge.net/projects/elphel, board 10353, camera hardware, Main page, Imaging solutions with Free software and open hardware
Just another FPGA+microcontroller example:
I do not think this means what you think it means... I read "...and a metal programmable (MP) block of 500K gates of digital logic." as meaning that it's a one-time programmable block, more akin to a standard-cell ASIC than an FPGA. This is supported by the fact that their development board contains a separate FPGA chip. Now, granted, having a 500K gate ASIC on board an ARM is a cool thing... but not quite as cool as this chip appeared at first glance.
- Samsung S3C2443 Up to 533 MHz, USB 2.0
This FPGA is just an example:
- Spartan-3AN FPGA Capabilities Quote: "...Simple and secure embedded application storage with up to 11Mb of integrated user Flash...Enable simple arithmetic and math functions as well as advanced DSP functions to derive over 330 Giga MACs/sec...Up to 32 18 x 18 embedded multipliers support 18-bit signed or 17-bit unsigned multiplication, and can be cascaded to support wider bits..."
- XC3S1400AN-4FGG676CES $91
- XC3S200AN-4FTG256CES $25.87
Tool for FPGAs
- xilinx.com: ISE WebPACK is the industry´s only FREE, fully featured front-to-back FPGA design solution for Linux, Windows XP, and Windows Vista
Asynchronous FPGA, AFPGA
128MB Dedicated for open files, running software etc., not for storage, or 256MB at all would be really nice and enough for any future software.
Enough to Hold O/S and a fair number of applications and their settings. Persistent Storage with XIP capability. About 128 MB.
An internal Micro SDHC should be used for users' files and additional software
Wireless data networking
WiMAX is a high-speed data service, similar to wifi, though longer range and newer. Where service is available, this would complement WiFi. Unfortunately, unlike wifi, frequencies vary worldwide, so global usage may be complex.
- Near Field Communication has a few centimeter range, useable for keys, ID badges, pairing bluetooth devices and similar uses. Mentioned in newer bluetooth and SD standards. (No products.)
- ZigBee is designed for connecting sensors and switches in buildings, with many options including mesh networks and aggressive power saving compared to bluetooth. (Almost no products available.)
- The ANT network is for connecting worn devices. Similar to ZigBee, but much simpler and maybe lower power. (Short list of products.)
- A camera that can take reasonable quality video and pictures is something many want. Applications vary from simple snapping, to gesture interfaces, video conferencing, barcode reading, buisness card reading, healthcare, servicing, and more.
- Some people can't take cameras into work - a model without the camera, or some way of removing the camera would be useful or leave the camera chip in place and have a removable lens assembly and replacement backcover.
- See Wishlist:Camera for a more detailed wishlist.
Main article: Spell weaving
See also this page containing a link to a video demonstration.
Bigger and better screen
262k or 16.7M colurs for displaying images and especially videos.
OLED for better contrast, more rich colours, and less energy consumption.
Distance sensing touchscreen
- Main article: Hardware:NearlyTouchScreen
TouchKo's (now Wacom Company Ltd.) spatial capacitive "touchscreen", can sense fingers at a small distance, so you do not get your display greasy, and can unlike some touchscreens, be operated with gloves.
Hardware acceleration for video playback and 2D/3D accelleration will be present in Neo1973 GTA02.
Or electronic paper display, EPD is used in many new devices such as the new Motorola motofone, sonys new e-reader and Irex's iliad. The technology provides thin, lightweight, power saving screens using new eink technology. This technology could cut the weight of the phone and its power usage. For more info see: eink's website.
Pro: laserprinter like quality, glossy, very stable image, easy on the eyes. Electronics are similar to TFT. Very low power consumption.
Con: Black and grey only (like a newspaper, but glossy), although there were already color prototypes in 2005. low framerate (5fps). Can reflect light (like paper), backlight is impossible.
It would be nice to have (the option of) a transreflective display, which while being less bright, is readable without needing to power the backlight. Then again, it depends on how much power the backlight uses compared to everything else...
"Slightly" Larger Screen
43mm x 57mm (2.8inch diagonal) is tiny. A 53mm x 71mm (3.5 inch diagonal) like on the TD035STEE1 would be a nice improvement. A widescreen format at about 53mm x 82.5mm instead of the 3:4 aspect ratio would be even cooler (if one could be found).
A 32x32 OLED display possibly on the back for camera framing or on an edge so it can be viewed like a pager. This could be used to display any number of alerts (from any installed software) the alerts could have a dynamic prioritisation which means during the work day a message from the boss has high priority but lower at home (could be GPS/Time controlled?) multiple alerts shrink the icons to a 3x3 grid higher priority messages get more space.
Like the one shown here, new cellphones are now coming out with a small, low power projector. This can be used to show movies from your cell phone with 0.5m high image on a while wall for example...
No Dependence on Stylus
The Neo's basic functionality should be completely usable without a stylus, Like the iPhone but with stylus use for precision work.
A laser projection keyboard
Similar to this, except the device would be integrated into the phone itself. Setting the Neo up on a stand on a flat surface (perhaps a stand could be built into the back of the Neo itself, or into a case) would turn the Neo into a micro-laptop. There may be several issues with the inclusion of this technology, including patents, the space required to project the laser grids, and the power consumption. If possible, however, it would make text input a breeze.
Just a few more Buttons
2 buttons more, 3 buttons total, mounted sideways would be enough. You could use them for play/pause and loudness controll while the phone remains in your pocket (display locked, ...), reading mails, rss, ebooks,... without wasting display space and so on.
With 5 buttons in total you could possibly emulate a keyboard (2^5 = 32 combinations) for those who know how to play a flute. Useable onehanded, not wasting display space and faster than t9. (It's not faster than T9 - I've used this system with the microwriter agenda --Speedevil 00:00, 2 July 2007 (CEST)) Hopefully this is not patented already.
D-Pad and Buttons
- Adding a D-pad (to the bottom of the phone) and 2 to 4 buttons (to the top) would provide some tactile input controls, in addition to the touchscreen. They could be used as shortcut keys in the menu, or playback control when playing media. When the phone is held sideways, they can be used as games controls. (With touchscreen alone, gameplay options are limited)
Game buttons would be best on both sides of the screen. The larger the buttons, the better. 2x 4 buttons in up-down-left-right configuration + some extra buttons separately a bit lower on the device would be good for many for emulation games.
Here is a concept drawing of a possible neo1973 gaming version:
(This has a 4-way direction pad, 8 way may be better for gaming)
Shoulder buttons would be a great addition, too. It would be interesting if there was a total 4 of them, one for every corner. It would make the phone very flexible for rotating and 2 to 6 players playing on one device.
- Note : The Tapwave Zodiac Palm PDA / Game console hybrid had a similar setup - with an analog stick on the left (also used for quick selection using a radial main menu when working as a PDA), 4 buttons on the right (also configurable for shortcuts when using the device as PDA), and 2 shoulder buttons. Also it had and still has an enthusiastic scene of homebrew development (almost any console emulator for PalmOS can also take advantage of the additional buttons and graphic power of the device). If we also take into account the success encountered by the GP32 in the past and the GP2X currently on the homebrew scene, it's not unreasonable to plan a future OpenMoko device with both a SmartPhone/PDA functionnality and hand-held console targeting homebrew development.
Thumb keyboard or keyboard attachment accessory
- Could be slide out or clamshell (hinge on long side) design with an external OLED. The keyboard should be protected when not in use.
- Could be a clip on keyboard that attaches to the serial port or communicates by bluetooth (not preferred for permanent keyboard users).
- Cheap clippable miniusb keyboard
- One of the layouts proposed in Hardware:Keyboards
- What about virtual keyboard? [Keyboard]
A trackball would provide an efficient mouse-like interface in a very compact package. As exemplified in the newer Blackberry® models. Maybe instead an optical sensor as are used in mice could be used so that the whole phone can be moved over a surface just like a mouse. (It could function as a Bluetooth mouse for other devices like laptop computers: see Bluetooth_Support#Acting_as_HID_device. Adding one other two-axis analogue input (possibly just the screen) would make the Neo usable as a TrackPoint or scroll-and-tilt mouse.) The same sensor might be usable as a barcode reader.
A joystick, or Rollermouse-like device would provide additional control, compared with touchscreen only.
- A standard pointing stick (ie. TrackPoint) might serve well. As a fairly standard part, might they be quite inexpensive?
Dual analogue controllers (one trackball or joystick above, one below the screen, most likely) might even be feasible. That might be overkill since the accelerometers or touchscreen can be used to provide a second analogue input. But it would be nice to have four axes of analogue control without having to tilt the screen away from you or partly cover it with your hand.
Digital Television, Digital Radio or even normal analogue TV/radio is widely available in the world, though unfortunately in various different forms. In markets where one standard is widespread, and hardware is suitable, it would be a great extension of the phone to a general entertainment device for when you're away from home. Multi standard devices would be ideal, but may not be small, low-power, or cheap. A good start would be an FM tuner, since it's one of the most widely used formats of radio broadcasting in the world.
This could be a good chip, though it's not clear if the drivers are open source. http://www.sigmatel.com/products/portable/wireless/fmtuner.aspx#fragment-14
This enables the phone to sense which direction 'down' is, and to sense any movements the phone makes.
See Accelerometer Fundamentals for more information on accelerometers as they may be used in phones.
In some cases integrated gyroscopes may also be needed. A #Digital compass can even be of more use since it gives absolute rotation so slow rotations could also be measured. A 3D compass would be nicest, but a simple 2D compass already is a helpful addition to the accelerometers.
- 3D Viewport
- Computer Mouse
- Determine Position
- Dynamic Screen Orientation
- Change media player playlist when jogging vs walking.
- Attempt to use to stabilise any future camera.
This feature is scheduled for inclusion in the phase 2 Neo1973, currently slated for release in October 2007.
Side-Mounted Touch Strip
Add a "touch strip" sensor onto the side of the phone which can be used to scroll. By having it on the side you can use your thumb to scroll comfortably while holding the phone one-handed. An 8-element capacitive sensor would work wonderfully and be easy to fab using either a Quantum QT411 (http://www.qprox.com/products/qslide_qt411.php) or Analog Devices AD7143 (http://www.analog.com/en/prod/0,2877,AD7143,00.html) controller. The Analog Devices chip seems better suited due to it's smaller allowable element size.
- With the AD7143 you can have an 8-element (128-position) 25mm long strip - Perfect!.
- With a few OLED screens beneath the strip it could be used as dynamic configurable buttons/alerts eg. zoom/flash/shutter with a camera application and SMS/Email/Voicemail alerts in standby
- Maybe it would be also possible to use is as finger print reader? --tolein 20:18, 1 October 2007 (GMT+1)
Heart Rate Compatibility
An RF interface to receive data from popular heart rate straps (Polar, Garmin, Sigma, Suunto, etc.). This would go along well with the existing GPS functionality and possible future Accelerometer functionality to make for a full-blown workout tool.
Software can be written to track heart rate along a running, cycling, skiing, swimming loop, to monitor max and min heart rate, to match heart rate data to GPS coordinates and print map data w/ relevant data.
A digital compass is useful for orienting maps to the terrain and other location/direction/orientation based applications (... is 300 meter that way) when the user is standing still (regardless of GPS reception) and for following a bearing when GPS reception is poor or speed is low. Also could be used to make the accelerometer data more exact.
Very small I2C sensors like Honeywell's HMC6352 2-Axis Digital Integrated Compass (6.5 x 6.5 x 1.5 mm) are very appropriate for this.
See Wishlist - Hardware: Digital compass for more information
An electronic thermometer might become handy for some users.
There are very small I2C devices available, that could easily integrate to the existing bus. For example this one from ti. (Could just be cheap and use the thermometer from the battery, thats how they did it in the nokia 5140's). Also is integrated in a barometer/altimeter like the SMD500 mentioned in Wish List - Hardware - Atmospheric.
Barometer and Variometer (Altimeter)
A Barometer measures air pressure. This can be used to give weather information, and also as a variometer, to sense relative altitude. Variometers are commonly used in flying microlight and ultralight aircraft, to get accurate relative altitude.
These are also common on high end GPS units. This is a great feature for walkers as you can tell how far you have got on any accent/decent.
See Wish List - Hardware - Atmospheric for more information.
Finger print sensor
A fingerprint sensor gives easy and fast access to the phone, could lock the touchscreen etc. An example of this device can be found at Sony UX17.
Most fingerprint sensors in the embedded market include a navigation mode, where they work similar to either a touch-stick or touch-pad of a laptop.
- less cpu intensive and more reliable than camera+ocr
- though, bluetooth-enabled readers are already available.
Ability to sense ambient light, and act accordingly. i.e if it's 3am and LightValue<.1 then Ring Quietly.
A navigation wheel like on a sony/ericsson 810i would be nice.
Switch off backlight when you place the phone to your ear. Prevent accidental activation of speakerphone or other sounds when the phone is near the ear (prevent hearing damage). Possibly switch the speakerphone on or off automatically depending on if the phone is by your head or not.
Make all unlocking of phone, password protected
When my (current non-neophone) phone is in my pocket and I have it locked, it sometimes accidentally unlocks itself since only two keystrokes in the correct order are necessary to unlock it. When it's unlocked and still in my pocket it sometimes calls someone without my knowledge. All phones I've seen today have a press-just-one-button bypass to answer an incoming call even when the phone is locked. I suggest making the locking mechanism let the user configure it so that the user has to enter a password even for answering incoming calls. The likeliness of the phone accidentally runbbing against my car keys, hitting a ten character long password, unlocking the phone without my knowledge and consent is low enough even for us most unlucky users.
Positioning of Buttons, Connections and ports
Ideally any cable ports such as charging, USB, audio, docking should not get in the way of your hand or fingers when holding it in it's normal orientation. For the sake of SDIO cards an external SD slot should be on the top edge. IR for remote control software and ease of inter-device communication should be on the corner so that it is facing away from you for both orientations. Buttons obviously are positioned for finger control. An example of how not to do this would be the HTC Universal
MMC/SD/SDIO slot (rather than?) miniSD or microSD
- Cheaper, more durable cards in a widely accepted format.
- Much much larger storage capacity, even 32GB
- Cards are harder to lose
- Wider selection of accessories, including SDIO accessories.
- Make externally available so that larger length SDIO cards can be used (thinking about SDIO WLAN here)
- SDHC compatible. It seems to already have the right hardware for it - see Neo1973_Hardware#microSD-Card.
Two SD slots
- Micro SDHC for /home partition. Keep like current design underneath SIM card
- Hot swappable externally accessible normal size SDHC/SDIO slot
- 5V Powered, to avoid having to carry around a hub for when you want to occasionally plug in a memory stick. Many powered hubs will not recognize a totally unpowered host. Provide a maximum current to drive a basic USB keyboard/memory stick/mouse/webcam/astrowebcam. This could be done by adding a small cheap power converter like the LM2753
- USB 2.0
- Standard type A socket for quick & easy insertion of memory sticks etc.
- OTG (is this maybe supported already ?)
- Bootable USB device emulation: the possibility to boot any computer on a bootable flagged partition of the transflash.
- Protection against incorrectly wired USB ports: some USB ports are wired incorrectly; if the +5V and GND are swapped, the device would get -5V when it's expecting +5V, which could burn some chips. A reverse-biased diode between +5V and GND, D+ and GND, D- and GND, and (if used) ID and GND, with a low enough forward voltage drop (to limite the negative voltages to what the chips can withstand), would protect the device by tripping the port's short circuit protection.
Wireless USB support
Wireless USB is the wireless version of USB offering data-rates up to 480 Mbit/s over short distances (<3 meter). Chipsets suitable for a phone are likely to take some time to be available.
SIR/FIR transceiver (Serial Infrared) / IR remote control
- An infrared transceiver is cheap, small, and useful for sync with many laptops and mobile phones.
- Replace/emulate all IR-based remote controls used for your tv, vcr, etc on your neo cell phone.
- replaces multiple 'dumb' devices with a single intelligent device (your neo) that you will probably carry with you at all times anyway.
- Command sets should be retrieved from a database or learned from other less intelligent remote control devices with macros.
- reduces clutter, particularly in the living room.
- inceases the neo's practical status as an 'always-have' device.
- Detecting reflections from inside of a caddy, and switching from active mode.
- FIR would be a nice option, as it's some 40 times faster than SIR.
- Through a docking port
- S-Video/Composite Out
- DVI Out
- The Neo1973 GTA02 will have LEDs of some sort behind at least one button. 
- A blinking LED would be a cheap, low power way to inform the user of new SMS/Email....
- An alternative to this would be for one small part of the LCD to be separately backlit.
- This requires the CPU and LCD to be somewhat active, to keep the LCD refreshed, but gives much more information.
- A Small OLED Screen could be used and display much more information than a LED with minimal power usage.
- For example a multicolor LED which pulses yellow for GSM/GPRS transmit, blue for Bluetooth/Wifi, green to indicate non-urgent information - missed call etc, red to indicate battery low or other urgent notices.
- The LED and button ideas could be combined: illuminated buttons.
- It must be possible to completely disable the LED to save power or other personal preferences.
For finding keys, or any other application. May also optionally pulse in time with ring, to make phone more visible. This is really well done in Nokia 5500.
Small FM transmitter to output to car, and other nearby radios.
Here is some summary/discussion of how hearing aid compliance rules work in the US. Specifically it would be nice to see the phone include a telecoil, which allows the phone to connect wirelessly to many standard hearing aids.
Mobile Communication options
Generic Access Network / Unlicensed Mobile Access
This technology requires cooperation from the cellular provider, but UMA/GAN is already offered by T-Mobile in the United States, and perhaps others in other countries. Allowing the user to roam from GSM to wifi, this technology can save the end user a significant amount of money, and also allow the user to deploy coverage where there was none before. There are only a few UMA capable phones currently, but it would be great if this could be made to work on a phase 2 type OpenMoko device.
Note that this features requires a more advanced access to the GSM modem. Special messages needs to be exchanged with the network.
Faster/better mobile connectivity.
GSM/GPRS is at best slow. An incremental improvement would be a radio with EDGE support. EDGE is an evolved GSM standard and, like GPRS, it operates on the same frequency as voice. This means a quad-band EDGE radio will have near-complete worldwide coverage.
UMTS - which is widespread in Europe and being deployed in the US, HSDPA (asia) and any other mobile standards would be nice for faster data connectivity and coverage. It is unlikely that all of these will be supported initially, but it is a goal. These faster standards operate in different frequencies from GSM/GPRS/EDGE. Which frequency exactly will depend on the carrier and country. For UMTS in the US, AT&T uses 850/1900 MHz but T-Mobile will use 2100/1700 MHz for example.
Until that goal is reached, it is likely that some phones will be brought out for various specific markets - Europe, Asia, US.
Ability to use multiple SIMs/networks
- External SIM sockets are widely available in China, a dual external socket would be a very good solution.
- Dual SIM card kit - two SIMs are trimmed and combined, software supportwould be needed, and both can't be used at once...
- Some networks support multiple numbers on one SIM. Unfortunately this won't allow split networks.
- A second/dual GSM module would allow full use of both sims at all times.
- As a hack, use another mobile via BT.
- As many as three SIM slots would be genuinely useful, especially for a 3G phone - some 3G data tariffs are only available on data-only SIMs. A user could quite reasonably have one SIM for data, once SIM for his personal voice calls, and a third SIM for his business number.
- Include a PMR/FRS Radio.
- A two-way walkie talkie lets you use the phone to communicate with friends without requiring a GSM connection (crowded networks at festivals, at locations with no GSM coverage).
- Include a DECT GAP/CAT-iq transceiver so you can use your home and/or office PSTN line
- Ability to use Alcatel phonebook stuff (like provided by the eventphone.de phone equipment) would be very nice too
Make stripped down (and thus cheaper) version of the Neo1973 phone for use as a SIP phone. Remove GPS, GSM, accelerometers, stilus.
Addition of an centimeters-precise location system RTLS would be nice, as it will allow highly sensible indoor context detection. Image to put the phone next to your mirror (where you shave daily) and observe it automatically switch to news radio channel. Or put it next to your bed and see it automatically switch to "sleeping" mode, when only calls from predefined numbers are accepted.
See also: Alternate Neo1973 case designs for a list of cases being considered for design/manufacture by the community.
- Replacement backs with additional features ranging from solar power, larger batteries, extra hardware, ...
Space efficient Lanyard
The hole at the bottom of the phone takes a lot of space. A Kensington Security Slot could be used instead.
We need something you can drop from 4 feet in to a puddle of dirty water on construction site. Sunlight readable display. The big ugly pseudo military version.
Make a transparent, see-through casing. Why do we need a closed casing for open hardware and open software? Show the world it is a truly Free/Open source phone.
Replacement fronts with e.g. extra buttons.
- A multi-standard satellite positioning module would be nice eventually, it does not seem to be near-term due to chipset availability problems. Galileo is the to be launched (2011) European positioning system. GLONASS is the already existing Russian one.
X10 RF Remote
Many PC-based media centers are being equipped with an RF (433 MHz) / X10-based remote control. The X10 protocol also facilitates home automation to control lamps, switches, etc. The advantages of using RF for control instead of Infra-red this that it also works when furniture, walls, or doors are blocking the path between RF remote and the equipment or device. Lirc supports X10-based RF remotes (but expects having an USB RF receiver attached to the media center).
RFID tag/RFID Reader
- Implementation/Cooperation with: RFID-Guardian
- An enable-able tag would be of use - for example being able to use the phone to open doors, or cars. Unfortunately, it's moderately hard to do secure programmable tags that are compatible with existing systems, for obvious reasons.
- Say you have RFID tags on your personal belongings: cellphone, keys... Neo could be programmed to remember the last recorded GPS location before it lost contact with the respective RFIDs. It'd be trivial to check where you left your cellphone, get directions from a map...or beep when the phone gets out of RFID range.
- A Near Field Communication chip, with this chip it will be possible to pay with your phone (like a credit card)in the near future, see Nokiafor details
- NXP is a chip fabricator which provides NFC chips NXP direct link>> www.nxp.com/#/pip/cb=[type=product,path=/53420/53424]|pip=[pfp=53424] their chips also support the above RFID reading
- Work on the weight of the Neo1973 and following devices. At the present time the Neo1973 is just a moderate / normal business or multimedia phone. The ordinary "user" may want something lighter. Take a look at the following table, that's the Neo1973 compared with other common bussiness or multimedia phones.
|Neo1973||Fujitsu-Siemens LOOX N560||E-Ten Glofiish X500+||Sony Ericsson P990i||iPhone||Nokia E65|
|184 g||160 g||146 g||150 g||135 g||115 g|
Make it smaller
- To stay within physical matters: Maybe the Neo1973 is also just a normal business/multimedia phone when looking at the size. It would be great the shrink it a bit. Especially the thickness of 18.5 mm could be worked on!
Standard 3.5mm headphone jack
The Neo1973 uses a 4-conductor 2.5mm jack for stereo headphones and a microphone. A 2.5mm jack is the most common for headsets.
There is an emerging convention used in the Nokia N800 and some other devices. A 4-conductor 3.5mm jack that can use a microphone with special headsets, but can also be used with off-the-shelf 3.5mm stereo headphones. Adapters to 2.5mm are of course available and this 3.5mm jack is much more robust.
Neglecting space limitations, multiple sockets - 2.5mm and 3.5mm would be nice. Probably not practical in a phone. Other expanded plugs might allow remote controls.
Other uses might be better met using bluetooth, or USB audio.
Include a built in laser pointer. Everything is better with lasers.
Completely free hardware
Consider selling one device with absolutely no non-free components in it, even if that means dropping the GSM support. I believe having one such device available would be good, because then it could be recommended by organizations like the FSF which typically never recommends anything if it has even a little non-free code in it.
Consider economy / inexpensive / less featured edition
Some people want less features, because they do not need them. Leaving out some features either lets the phone get smaller or possibly enhances battery live.
One big suggestion in this area is a b/w lower res display instead of the big color display.
It would be nice if it was possible to charge the phone without having to connect a cable. I'd like to have a simple docking station with an inductive charger like the type that's used for electric toothbrushes . The charger itself could get its power from a standard wall-wart power supply, or it could be USB/Firewire powered.
See Related Hardware