3 This is a hardware True Random Number Generator that attaches via USB.
7 This one uses the better noise source coupled with an op amp that
8 provides 2MHz of bandwidth at a gain of 100, offering linear frequency
9 response at a million samples per second.
11 A photo of prototype version 0.3:
13 <a href="v0.3/chaoskey-v0.3.jpg"> <img src="v0.3/chaoskey-v0.3-thumb.jpg"></a>
15 Here's a circuit diagram of the noise source:
17 <img src="v0.3/noise-source.svg">
19 ### Version 0.3 Hardware ###
21 * [STM32F042](http://www.st.com/web/catalog/mmc/FM141/SC1169/SS1574/LN1823?icmp=stm32f0x2-line_pron_pr_jan2014&sc=stm32f0x2-pr) System-on-Chip
26 * Crystal-less operation
28 * AP3015A boost regulator
29 * back-to-back 3904 transistor noise
30 * [OPA356](http://www.ti.com/product/opa356) op amp
35 This version uses a better noise source, but the single transistor amp
36 designed to get from the 20mV noise source to a digital value doesn't
37 provide enough bandwidth, so the resulting signal seen by the CPU has
38 poor frequency response.
40 Here's a photo of prototype version 0.2:
42 <a href="v0.2/chaoskey-v0.2.jpg"> <img src="v0.2/chaoskey-v0.2-thumb.jpg"></a>
44 ### Version 0.2 Hardware ###
46 * [STM32F042](http://www.st.com/web/catalog/mmc/FM141/SC1169/SS1574/LN1823?icmp=stm32f0x2-line_pron_pr_jan2014&sc=stm32f0x2-pr) System-on-Chip
51 * Crystal-less operation
53 * AP3015A boost regulator
54 * back-to-back 3904 transistor noise
58 These are photos of prototype version 0.1:
60 <a href="v0.1/chaoskey-v0.1-top.jpg"> <img src="v0.1/chaoskey-v0.1-top-thumb.jpg"></a>
61 <a href="v0.1/chaoskey-v0.1-bottom.jpg"> <img src="v0.1/chaoskey-v0.1-bottom-thumb.jpg"></a>
63 ### Version 0.1 Hardware ###
65 * [NXP LPC11U14](http://www.nxp.com/products/microcontrollers/cortex_m0_m0/LPC11U14FHI33.html) System-on-Chip
70 * 8 12-bit analog inputs
71 * I2C, SPI, async serial
73 * ZXRE1004 zener diode noise source
79 * [AltOS](../AltOS/) is written mostly in C with some ARM assembler
81 * [gEDA](http://www.gpleda.org/) for schematic capture and PCB layout
82 * [GCC](http://gcc.gnu.org/) compiler and source debugger
84 * The hardware is licensed under the [TAPR](http://www.tapr.org) [Open Hardware License](http://www.tapr.org/ohl.html)
85 * The software is licensed [GPL version 2](http://www.gnu.org/licenses/old-licenses/gpl-2.0.html)
89 The hardware design files can be found on [git.gag.com](http://git.gag.com)
90 in the project [hw/usbtrng](http://git.gag.com/?p=hw/usbtrng;a=summary).