mirror of https://github.com/akuker/RASCSI.git
Created Supercapacitor UPS (markdown)
parent
9a5778ea91
commit
9d5bebfe9d
|
@ -0,0 +1,25 @@
|
|||
# Background
|
||||
|
||||
The RaSCSI service caches data in RAM. When power is pulled from a RaSCSI/Raspberry Pi setup, it is possible to lose some or all of this data. In order to allow a graceful shutdown of the RaSCSI service and the Raspberry Pi OS, a USP can be added to the assembly. This way, when power is removed, the Raspberry Pi will have enough saved power to properly shut down.
|
||||
|
||||
# Prototype Phase: Dr. Scott M. Baker design
|
||||
|
||||
Dr. Scott M. Baker has designed two different UPS versions that will work with the RaSCSI. He has generously made these available on this blog for other people to use.
|
||||
|
||||
<iframe width="560" height="315" src="https://www.youtube.com/embed/j5Bv8r3TVPM" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
|
||||
|
||||
## Assembly
|
||||
![image](https://user-images.githubusercontent.com/34318535/165860429-e71abe1e-e8b8-42eb-8194-94afd55ff2b6.png)
|
||||
|
||||
For akuker's initial prototype, he started with the [gerber files](https://github.com/sbelectronics/ups/tree/master/gerbers/12v) provided by Dr. Baker. At the time of this writting, ATTiny85 chips are in very short supply. However, I was able to acquire some through [Amazon] in small volumes. (https://smile.amazon.com/gp/product/B06W9JBJJ6/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1) The rest of the parts were ordered from Digikey:
|
||||
![image](https://user-images.githubusercontent.com/34318535/165860847-f07941f5-336a-48c2-bd18-9706a9f4d247.png)
|
||||
|
||||
Note that for my initial prototype, I did not populate all of the connectors. I also did not populate the voltage dividers on the USB port (R15, R16, R17, R18). The "ORK" buck converter used by Dr. Baker was also not available. For one prototype, I used a [7805TV voltage regulator](https://www.sparkfun.com/datasheets/Components/LM7805.pdf). For the other, I bodged in a [LM2596S voltage regulator](https://www.ti.com/lit/ds/symlink/lm2596.pdf?ts=1651114146845&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FLM2596%253Futm_source%253Dgoogle%2526utm_medium%253Dcpc%2526utm_campaign%253Dapp-null-null-GPN_EN-cpc-pf-google-wwe%2526utm_content%253DLM2596%2526ds_k%253DLM2596%2526DCM%253Dyes%2526gclid%253DCj0KCQjw06OTBhC_ARIsAAU1yOUmvCB1WjcI1iKPeRtjK6ZXnT-MiqXwZSRntonhIAZ8ne8dBUrtJYsaAkxREALw_wcB%2526gclsrc%253Daw.ds), which has a higher amperage rating.
|
||||
|
||||
## Programming the ATTiny85
|
||||
|
||||
For programming the ATTin85, I followed these instructions: https://create.arduino.cc/projecthub/arjun/programming-attiny85-with-arduino-uno-afb829
|
||||
|
||||
# "Official" RaSCSI version
|
||||
|
||||
For the RaSCSI, akuker will be focusing on the 12v version of Dr. Baker's UPS. A modified version of this is being designed and will be offered in the Tindie store (when it is ready).
|
Loading…
Reference in New Issue