{"id":16956412,"url":"https://github.com/bgamari/open-pd","last_synced_at":"2025-04-11T21:43:39.833Z","repository":{"id":25670343,"uuid":"29106170","full_name":"bgamari/open-pd","owner":"bgamari","description":"An open-hardware photodiode amplifier and optical power meter","archived":false,"fork":false,"pushed_at":"2017-05-26T01:13:59.000Z","size":455,"stargazers_count":13,"open_issues_count":0,"forks_count":5,"subscribers_count":5,"default_branch":"master","last_synced_at":"2025-04-06T13:17:22.475Z","etag":null,"topics":[],"latest_commit_sha":null,"homepage":"","language":"Jupyter Notebook","has_issues":true,"has_wiki":null,"has_pages":null,"mirror_url":null,"source_name":null,"license":null,"status":null,"scm":"git","pull_requests_enabled":true,"icon_url":"https://github.com/bgamari.png","metadata":{"files":{"readme":"README.mkd","changelog":null,"contributing":null,"funding":null,"license":null,"code_of_conduct":null,"threat_model":null,"audit":null,"citation":null,"codeowners":null,"security":null,"support":null}},"created_at":"2015-01-11T21:09:22.000Z","updated_at":"2024-11-27T12:19:58.000Z","dependencies_parsed_at":"2022-09-20T19:26:32.968Z","dependency_job_id":null,"html_url":"https://github.com/bgamari/open-pd","commit_stats":null,"previous_names":[],"tags_count":0,"template":false,"template_full_name":null,"repository_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/bgamari%2Fopen-pd","tags_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/bgamari%2Fopen-pd/tags","releases_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/bgamari%2Fopen-pd/releases","manifests_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories/bgamari%2Fopen-pd/manifests","owner_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners/bgamari","download_url":"https://codeload.github.com/bgamari/open-pd/tar.gz/refs/heads/master","host":{"name":"GitHub","url":"https://github.com","kind":"github","repositories_count":248487166,"owners_count":21112185,"icon_url":"https://github.com/github.png","version":null,"created_at":"2022-05-30T11:31:42.601Z","updated_at":"2022-07-04T15:15:14.044Z","host_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub","repositories_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repositories","repository_names_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/repository_names","owners_url":"https://repos.ecosyste.ms/api/v1/hosts/GitHub/owners"}},"keywords":[],"created_at":"2024-10-13T22:14:57.549Z","updated_at":"2025-04-11T21:43:39.795Z","avatar_url":"https://github.com/bgamari.png","language":"Jupyter Notebook","funding_links":[],"categories":[],"sub_categories":[],"readme":"OpenPD — Open-source photodiode amplifier\n=========================================\n\nOpenPD is a low-cost, high dynamic range photodiode amplifier,\ndesigned for use as a low-bandwidth laser power meter. The device can\nbe used either autonomously or as a USB device.\n\nThe device is built using easy-to-solder 0805 surface mount\npassives. The device consists of a compensated transimpedance\namplifier with a wide range of gains switched with a network of analog\nmultiplexers. Since dual amplifiers are cheap, an additional voltage\ngain stage is included after the transimpedance amplifier, providing\nanother factor of 10 in gain (albeit with the additional noise that this\nimplies).\n\nNote that the capacitance and leakage current of these multiplexers\nlimit the frequency response and low-current linearity of the\ndevice. This is acceptable for the intended use-case, which targets\ngeneral purpose intensity measurements of constant-wave lasers.\n\nThe Hamamatsu S2281 photodiode is a convenient photodiode for use with\nthis device. With this diode the device has been shown to resolve from tens of\nnanowatts to hundreds of milliwatts.\n\nThe device is designed using the [gEDA][] electronic design suite.\n\n[gEDA]: http://geda-project.org/\n\nSpecifications\n--------------\n\n * Analog bandwidth: 1 kHz\n * Digital sampling rate: Up to 200 ksamples/second\n * Sampling resolution: 16 bits\n * Current amplifier gain ranges (Digitally switched):\n     * 5 megavolt / amp\n     * 33 kilovolt / amp\n     * 150 volt / amp\n     * 1 volt / amp\n * Theoretical sensitivity: Around 100 nA\n * Realistic sensitivity: We'll see\n * Maximum measurable current: 10mA\n * Additional voltage gain of 10 after amplifier; both channels can be read by ADC\n * Interface:\n     * USB device\n     * SPI [OLED display](http://www.ebay.com/itm/131305379698) and buttons\n * Power:\n     * USB\n\t * 5V power input\n\t * 3.7V lithium polymer battery\n\nParts\n-----\n\n| Vendor            | Part            | Qty | Description                        |\n|:------------------|:----------------|:----|:-----------------------------------|\n| Analog Devices    | ADG733          | 2   | Analog multiplexer                 |\n| Freescale         | MK20DX32VLF5    | 1   | Microcontroller                    |\n| Texas Instruments | OPA2376AIDR     | 1   | Dual operational amplifier         |\n| Texas Instruments | TMP100NA        | 1   | I²C temperature sensor             |\n| Texas Instruments | LP5907MFX-3.3   | 1   | 3.3V Low-dropout voltage regulator |\n| Amphenol          | 132289          | 1   | End-launch SMA jack                |\n| C\u0026K Components    | PTS810 SJK 250  | 7   | Tactile switch                     |\n| FCI               | 10104111-0001LF | 1   | Micro USB connector                |\n| JST               | S2B-PH-SM4-TB   | 1   | LiPo Battery connector             |\n\nThe passive components are all 0805 packages.\n\n| Value        | Qty |\n|:-------------|:----|\n| *Capacitors* |     |\n| 10 nF        | 1   |\n| 100 nF       | 13  |\n| 1 uF         | 1   |\n| 10 uF        | 2   |\n| 330 pF       | 1   |\n| 4700 pF      | 1   |\n| 58 nF        | 1   |\n| 680 nF       | 1   |\n| *Resistors*  |     |\n| 1 ohm        | 1   |\n| 100 ohm      | 2   |\n| 10 kohm      | 3   |\n| 150 ohm      | 1   |\n| 1 kohm       | 3   |\n| 33 kohm      | 1   |\n| 5 Mohm       | 1   |\n| *Choke*      |     |\n| 1uH          | 1   |\n\nResources\n---------\n\n * Microchip application note AN951 \u003chttp://www.microchip.com/wwwAppNotes/AppNotes.aspx?appnote=en021228\u003e\n * Analog Devices' *Analog Dialogue* 47-05 (May 2013) \u003chttp://www.analog.com/library/analogdialogue/archives/47-05/pgtia.pdf\u003e\n * Datasheets of above parts\n * Horowitz and Hill. *The Art of Electronics*\n * Mancini, R. *Op Amps for Everyone*\n * Hobbs, Phillip C. D. *Building Electro-Optical Systems: Making It All Work*\n * Hobbs, Phillip C. D. \"Photodiode Front Ends: The Real Story\" *Optics and Photonics News* (April 2001)\n","project_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fbgamari%2Fopen-pd","html_url":"https://awesome.ecosyste.ms/projects/github.com%2Fbgamari%2Fopen-pd","lists_url":"https://awesome.ecosyste.ms/api/v1/projects/github.com%2Fbgamari%2Fopen-pd/lists"}