Hardware hacker bunnie Huang‘s latest project is a mobile device called Precursor. While it looks a bit like a phone or PDA, Huang describes it as a “mobile, open source electronics platform” designed for development purposes.
It’s set to go up for pre-order through a Crowd Supply crowdfunding campaign soon, but Huang has published a blog post explaining the project and there are plenty of details on the Crowd Supply preview pages.
Update: The crowdfunding campaign went live on November 1, 2020 and backers can pre-order the Precursor at Crowd Supply for $450 and up (or $512 and up once early bird rewards are gone). If the campaign is fully funded, the first units could begin shipping to backers by December, 2021.
The idea behind the Precursor isn’t to provide a device that can replace your smartphone or tablet, but rather to offer a system that you have nearly complete control over.
Instead of a traditional CPU, it has an FPGA that allows users to program the chip so it emulates many different types of processor, giving you far more control over the hardware than you’d have from a typical mobile device.
Out of the box, the FPGA will be configured to work as a 100 MHz, 32-bit RISC-V CPU, but it can be configured to emulate many older processor types. Just keep in mind that it tops out at 100 MHz speeds. Huang says the system will be more powerful than a Palm Pilot or Nintendo DS, but it’s best suited for developers who want to create a single-purpose device completely from scratch… and if you want to create a mobile device that accomplishes a different task then you can adjust the hardware and software settings and start over again.
The Precursor’s hardware is designed to be entirely inspectable and understandable by a single knowledgeable user. As Huang notes, “Even though the full source code for the Linux kernel and Firefox is published, nobody has the time to personally review every release for potential security problems; we simply trust that others have done a good job, because we have no other choice.” So this device is intentionally simple.
The Precursor’s hardware includes:
- Xilinx XC7S50 primary System on Chip (SoC) FPGA
- iCE40UP5K secondary Embedded Controller (EC) FPGA
- 16 MB external SRAM
- 128 MB FLASH
- 536 x 336 pixel black and white display (200 pixels per inch)
- Physical keyboard with changeable layout overlays (backlit)
- 0.7 W speaker
- Vibration motor
- 3.5mm headphone jack (but no integrated microphone)
- SiliconLabs WF200C WiFi chipset (sandboxed)
- USB-C port
- 1,100 mAh battery
- Anti-tamper features
Huang says users should expect about 5.5 hours of battery life when using the device, or 100 hours of standby time. It takes about 3 hours to fully recharge the battery.
The device measures about 138 x 69 x 7.2mm and weighs 96 grams, making it smaller and lighter than most modern smartphones. It has an aluminum alloy case, but 3D design files will be available for those that want to produce their own cases.
There’s also no adhesive holding the Precursor device together. You can open it up with a screwdriver and add a cellular modem or other hardware that’s not included.