Slashdot Mirror
ESR's Newest Project: An Open Hardware/Open Source UPS (ibiblio.org)
An anonymous reader writes:
Last month Eric S. Raymond complained about his choices for a UPS (Uninterruptible Power Supply), adding that "This whole category begs to be disrupted by an open-hardware [and open-source] design that could be assembled cheaply in a makerspace from off-the-shelf components, an Arduino-class microcontroller, and a PROM...because it's possible, and otherwise the incentives on the vendors won't change." It could be designed to work with longer-lasting and more environmentally friendly batteries, using "EV-style intelligent battery-current sensors to enable accurate projection of battery performance" (along with a text-based alert system and a USB monitoring port).
Calling the response "astonishing," Raymond noted the emergence within a week of "the outlines of a coherent design," and in an update on GitLab reported that "The response on my blog and G+ was intense, almost overwhelming. It seems many UPS users are unhappy with what the vendors are pushing" -- and thus, the UPSide project was launched. "We welcome contributors: people with interest in UPSes who have expertise in battery technology, power-switching electronics, writing device-control firmware, relevant standards such as USB and the DMTF battery-management profile. We also welcome participation from established UPS and electronics vendors. We know that consumer electronics is a cutthroat low-margin business in which it's tough to support a real R&D team or make possibly-risky product bets. Help us, and then let us help you!"
There's already a Wiki with design documents -- plus a process document -- and Raymond says the project now even has a hardware lead with 30 years experience as a power and signals engineer, plus "a really sharp dev group. Half a dozen experts have shown up to help spec this thing, critique the design docs, and explain EE things to ignorant me." And he's already touting "industry participation! We have a friendly observer who's the lead software architect for one of the major UPS vendors." Earlier Raymond identified his role as "basically, product manager -- keeper of the requirements list and recruiter of talent" -- though he admits on his blog that he's already used a "cute hack" to create a state/action diagram for the system, "by writing a DSL to generate code in another DSL and provably correct equivalent C application logic."
He adds to readers of the blog that if that seems weird to you, "you must be new here."
Calling the response "astonishing," Raymond noted the emergence within a week of "the outlines of a coherent design," and in an update on GitLab reported that "The response on my blog and G+ was intense, almost overwhelming. It seems many UPS users are unhappy with what the vendors are pushing" -- and thus, the UPSide project was launched. "We welcome contributors: people with interest in UPSes who have expertise in battery technology, power-switching electronics, writing device-control firmware, relevant standards such as USB and the DMTF battery-management profile. We also welcome participation from established UPS and electronics vendors. We know that consumer electronics is a cutthroat low-margin business in which it's tough to support a real R&D team or make possibly-risky product bets. Help us, and then let us help you!"
There's already a Wiki with design documents -- plus a process document -- and Raymond says the project now even has a hardware lead with 30 years experience as a power and signals engineer, plus "a really sharp dev group. Half a dozen experts have shown up to help spec this thing, critique the design docs, and explain EE things to ignorant me." And he's already touting "industry participation! We have a friendly observer who's the lead software architect for one of the major UPS vendors." Earlier Raymond identified his role as "basically, product manager -- keeper of the requirements list and recruiter of talent" -- though he admits on his blog that he's already used a "cute hack" to create a state/action diagram for the system, "by writing a DSL to generate code in another DSL and provably correct equivalent C application logic."
He adds to readers of the blog that if that seems weird to you, "you must be new here."
There is probably a lot of potential for open electronics instruments as well. Multimeters, oscilloscopes, low end audio and RF spectrum analyzers and such. Dave Jones has had a very well received (AU$ 644,674) Kickstarter project with the 121GW multimeter. It's not entirely open (the firmware is proprietary,) but the hardware is open (schematics, components details, etc.,) the MCU is an easy to deal with STM32 and the programming headers are deliberately easy to get at, so ultimately open source firmware will emerge.
Maw! Fire up the karma burner!
Bulk of the consumer grade UPS are based off sealed lead acid - fairly idiot proof but only moderate charge capacity, limited peak draw capacity and limited life (normally the battery capacity has seriously degraded after two years of continuous service).
Making the battery user replaceable would be a big step in the right direction.
Shifting to Lithium Ion cells (preferably the iron phosphate variant) and applying a little de-rating will significantly improve the situation (requires a charge management circuit but these can be easily be sourced). The manufacturers' data sheets state to charge lithium ion cells to 4.2 volts per cell, keep the charge limited to 4.1 or even 4.0 volts per cell will dramatically increase the life of the cells (leave this as an exercise for the reader to research).
If you want to make the equipment "industrial rated" then component ratings need to be reviewed. Capacitors are available in various voltage ratings however if you want the equipment to last 10 years in +100F/+40C conditions then the voltage rating needs to be nearly double the normal operating voltage (there is a study done/sponsored by one of the US military branches on longevity and component ratings).
There is some fairly heavy engineering required on the power side of stuff and I don't believe ESR has yet to wrap his head around all the issues. Perhaps that is why he has put the call out for assistance.
Already exists, it's called OpenUPS and NUC-UPS. In fact OpenUPS is pretty close to what ekr is proposing, only it already exists as a finished product. Guess he didn't do much Googling before he came up with his one...