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OPEN Power

I didn't have enough to buy a Lab Bench PSU... So I made one.

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Open Power is about providing Makers, Students, and Hobbyist with a Portable, Versatile Intuitive and Cheap power supply for all their projects.

Prototype 1: Simple and Cheap Constant Voltage/ Constant Current Power Supply variable from 0.6V to 12V with led voltage indication. USB Load sharing powered and Lipo backup. (cost under $2.65)

Prototype 2: A Constant Voltage Constant Current Power Supply 0.6V to 12V In addition to an adjustable Negative Rail. Voltage and current Monitoring Provided by a OLED Display. (cost estimate under $5.50).

Prototype 3: Utilizes a Boost Inverting IC to get +-13V and LDO's to Reduce the voltage between 0 and 12V. Both +- Rail Voltage Current and Power will Be displayed on a Full Color LED Display. and SD card for power Tracking and oscilloscope/Logic analyzer (cost estimate under $15.50)

The goal of Open Power is not to replace the desktop power supply or oscilloscope but to provide an entry level experience for all.

The goals of OPEN Power is to produce 3 final Prototypes. All Power Supplies will have USB Charging of Lithium polymer batteries and a Load Sharing and Uninterruptible power when disconnected. 

Product Line Comparison

Prototype 1a:

---------------------
Status
(COMPLETED)
Simple Constant voltage Power Supply
Variable from 0.6V to 12V
.
Will Include 5V and 3V Rails.
Voltage indicator will be achieved using comparators and LED Array.
This was chosen to reduce cost
as much as possible and keep
each board with components
 under $2.75.



Schematic (LINK)

BOM (LINK)

Gerber Files (LINK)
Prototype 1a: Rendering
Prototype 1a: Rendering
Prototype 1a: Assembled
Prototype 1a: Assembled
Voltage Test
Voltage Test
Load Sharing and Quick disconnect Test
Load Sharing / Uninterruptible Test
Prototype 1b:
---------------------
Status
(Sent To
 the Fab
8/27/2019)
Revision 1b The Led arrays are
switch from a linear array to a
polar array
around the Voltage
and Potentiometer trimmers
have been added to calibrate.


BOM (LINK)

Prototype 1B: Rendering
Prototype 1B: Rendering
Prototype 1B: Rendering
Prototype 1B: Rendering

Prototype 1B: Power Test
Prototype 1B: Power Test
Prototype 1c:
Status
(Layout Mock-up)
Revision 1c will add an additional 
Constant Current 
Knob to allot
user to limit current and see
around what current is being
drawn (10mA Increments). 


Prototype 1C: Rendering
Prototype 1C: Rendering
Prototype 1C: Rendering
Prototype 1C: Rendering

Prototype 2A:A Constant Voltage Constant
current Power Supply 0.6V to 12V.
In addition to an adjustable
Negative Rail. Voltage, Current
and Power
of the positive Rail will
be displayed on a compact
OLED. Negative Rail
Voltage will also Be displayed
as well as the Battery Voltage.
Prototype 2A: Rendering
Prototype 2A: Rendering
Prototype 2A: Rendering
Prototype 2A: Rendering
Prototype 2A: Rendering
Prototype 2A: Rendering

Prototype 3:
---------------------
Status (COMPLETED)
Utilizes a Boost Inverting IC to get
+-13V and LDO's to Reduce the
Voltage between 0 and 12V.
Both +- Rail Voltage, Current
and Power
will Be displayed
on a Full Color 0.96" LED
Display
.


(COMPLETED Some errors see Schematic)


Schematic (LINK)
Prototype 3A - Render
Prototype 3A: Rendering
Prototype 3A: Assembled
Prototype 3A: Assembled
Prototype 3A: Load sharing Test
Prototype 3A: Load sharing Test
Prototype 3A: Constant Current Test
Prototype 3A: Constant Current Test
Prototype 3b:
--------------------- 
Status 
(Sent To
the Fab 8/28/2019)
Revision 3b will have a DAC
Output,  2 Analog input
and 4 DIO Pins
.

The implementation of a
16-Bit ADC
Will improve the Current Readout


                (Sent to the Fab)

Update - design Errors made and sent back to the fab


Schematic (LINK)
Prototype 3B: Rendering
Prototype 3B: RenderingPrototype 3B: Layout
Prototype 3B: Layout
Prototype 3B: Layout
Prototype 3B: PCB Traces
Prototype 3B: PCB Traces
Prototype 3B: Schematic
Prototype 3B: Schematic

Prototype 3c:
---------------------  
Status  
(Layout Mock-up)
Revision 3c will switch from the
Samd21 to the Samd51 for faster
Procecesing power and additional IOs. 
The LCD will also be upgraded
 to a 1.3" IPS 240x240 LCD. 
Since the circuit is completely
analog the MCU can perform 
Double duty and Potentially  be
used as a Crude Oscilloscope
or Logic Analyzer.
Prototype 3C: Layout Mockup
Prototype 3C: Layout Mock-up
Prototype 3C:  Rendering
Prototype 3C: Layout Mock-up

Open Power - Comparison.pdf

Open Power - Product Line Comparison Vs Competition

Adobe Portable Document Format - 6.72 MB - 08/29/2019 at 16:26

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Open Power - Prototype1A - Gerber.zip

OPEN Power - Prototype 1A - Gerber Files Formatted for JLBPCB

Zip Archive - 435.96 kB - 08/25/2019 at 03:11

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Open Power - Prototype 1B.pdf

OPEN Power - Prototype 1B - Schematic

Adobe Portable Document Format - 662.95 kB - 08/25/2019 at 02:59

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Open Power - Prototype 1B - BOM.pdf

OPEN Power - Prototype 1B - BOM

Adobe Portable Document Format - 37.02 kB - 08/25/2019 at 02:56

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Open Power - Prototype 3B.pdf

OPEN Power - Prototype 3B - Schematic

Adobe Portable Document Format - 816.20 kB - 08/23/2019 at 04:51

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View all 8 files

  • 2 × MT3608 Boost Converter Modified to be a Sepic Boost.
  • 1 × MIC5225-5.0 5V LDO
  • 2 × LED - 0603 - Yellow LED - 0603 - Yellow
  • 2 × LED - 0603 - Orange LED - 0603 - Orange
  • 3 × LED - 0603 - Red LED - 0603 - Red

View all 45 components

  • 1B Boards are in!

    John Loeffler4 days ago 0 comments

    Received Prototype 1B Boards back from the fab.  1B is to test the range of the Potentiometer and the spacing of the leds.  1b Is not meant to be sold.  It is a test for 1C with will integrate constant current and therefor the voltage may not be the same as the set voltage.  Use Manufacture PCBway and was a little disappointed by the quality of the Silkscreen

  • Open Power - Prototype 2A - Mockup Renderings

    John Loeffler08/28/2019 at 15:12 0 comments

    Prototype 2A implements an OLED upgrade allowing users a graphic feedback.  In addition to reducing board size.   The Right Rail was changed to be an adjustable negative rail and has its folding displayed on the OLED.  Further iterations would include different size OLEDs.

  • Open Power - Prototype 1C - Mockup Renderings

    John Loeffler08/27/2019 at 16:51 0 comments

    Prototype 1C implements a constant current feature by sensing the ground current and toggling  the Feedback pin to the SEPIC converter.  If the current exceeds the value set by the current knob the Feedback pin is toggled high reducing the voltage to maintain the current.


  • Prototype 1B: Designed and sent to the FAB

    John Loeffler08/25/2019 at 03:09 0 comments

    Prototype 1B Makes improvement to the 5V boost converter as well as orients the LEDs arroung the potentiometer.  Because the Potentiometer is very inaccurate, a Trimmer potentiometer is used to calibrate the Voltage knob to the LEDs.  Calibration method will be developed.  1b was Fabricated and sent to Manufacture,

  • Open Power - Prototype 3C - Mockup Renderings

    John Loeffler08/23/2019 at 14:22 0 comments

    The Samd51 is a bit more complicated than initial thought so i made a Mock-up of Prototype 3 which uses a bigger 1.3in screen which requires the SAMD51 120MHz Clock power.  A demo layout of the UI was included in the Render to show it is capable of being a crude oscilloscope or logic analyses .

  • Open Power - Prototype 3B Finished and sent to be Fabricated

    John Loeffler08/23/2019 at 04:45 0 comments

    Prototype 3B made the corrections to the negative rail.  A new 16-bit ADC will improve the current measuring capability to the 100uA level.  Traces were done manually and verified. 


  • Prototype 3A: Load sharing/ Constant Current Test

    John Loeffler08/21/2019 at 23:44 0 comments

    Power is drawn from usb until disconnected.  Power remains on an powering LED

    Constant Current Test With an LED

  • Prototype 3A: Design and Assembly

    John Loeffler08/21/2019 at 17:04 1 comment

    Prototype 3a:

    I have got the board of  Prototype 3a back from the fab and populated it and uploaded the code.  Most functionality is working.  

    Problems:

    1) Current limiting on negative rail does not work.  There was an error in the Schematic

    2) The Positive rail only goes down to 0.62V when there is No load.  This is because the LT3081 Requires a 5mA Load for line regulation. 

    Prototype 3b: Revision Concept Includes DAC Output, 2X Analog Inputs(0-12V) and 4x Digital Inputs 3.3V (5V Tolerant)

  • Variable Voltage / Load Sharing / Uninterruptible Power Tests

    John Loeffler08/19/2019 at 19:50 0 comments

    Testing the SEPIC Converter and LED Feedback of the adjustable rails.  The pot is calibrated by an additional bot on the bottom for accurate voltage readings.  When the LED begins to flicker it is almost at the desired voltage.  When it just becomes solid it is at the desired voltage.

    When USB Power is applied the battery is disconnected and will be charged if needed.  When Usb is disconnected the battery will be enabled allowing continuous operation.

  • Corrected Boards Recieved

    John Loeffler08/18/2019 at 22:46 0 comments

    I got the Fixed Boards Back from JLBPCB and the work perfectly

View all 15 project logs

  • 1
    Hackaday Prize Q and A

    i. Is this a unique solution to a particular challenge facing the world today?

    Power Supply and Oscilloscopes are an Invaluable pieces of equipment for Engineers, Hobbyist, and Student.  It allows them to test their circuits under a variety of voltage and current conditions.  The problem is the are bulky, stationary, and expensive.  With release of these cheap Battery power supplies that attach to the breadboards users can make their projects mobile.

    The goal of Open Power is to take it a few steps further.  To integrate Lithium Rechargeable batteries. Quick Disconnect and a Variable Rail (0.6V -12V).  With Iterations capable of Constant Current, Current Monitoring, Digital I/O indicators, Voltage Reads, Crude Oscilloscope and Logic Analyzers.

    All These features with an aim at keeping cost as low as possible.  With our cheapest unit (Less than $2.50 Cost) multiple units can be Purchased and used in multiple projects.  This solves the problem of having to disconnect the circuit from the power supply to start a new project.

    Open Power will NOT replace the bench top power supply or oscilloscope, But it will supplement them and allow greater access to Students, Hobbyist and Makers.

    ---------------------------------------------------------------------------------------------------------------------------

    ii. How thoroughly documented were the design process & design decisions?

    The Design Considerations were based on many factors But it boils down to the 3 Basic Designs with improvement iterations.

    ---------------------------------------------------------------------------------------------------------------------------


    Prototype 1 A was designed to be the cheapest unit available.  Focus is to provide users with a Usb Chargeable unit  with 5 and 3.3v outputs as well as an adjustable rail (0.6V - 12V).  Prototype 1A accomplished this with the brute force method and comprised of 133 Components.  The Fabrication came back and was successfully tested.  Ideas of improvement from the Hackaday community sparked a design iteration that would indicate the Voltage even when the device was powered off. 

      (Status: Complete)

    ---------------------------------------------------------------------------------------------------------------------------

    Prototype 1B took those considerations and moved the adjustment knob to the center and arranged the LEDs around the voltage control knob.  This allows the user to see the set voltage even before it is turned on.  This offers a problem that not all Potentiometers are accurate and may not line up with the LEDs. To solve this a potentiometer bridges the voltage knob to set its range. and the Lower feedback resistor will be used to set the 0.6V.  In addition, most of the resistors were switched to resistor arrays which offer a tighter layout and easier reflow.  The Boards height as also reduced from 50mm to 38mm, offering a more compact form Factor.

      (Status: Currently being Fabricated)

    ----------------------------------------------------------------------------------------------------------------------------

    Prototype 1C took it one step further and integrated a constant current knob.  This works by measuring the load current at the low end and toggling the feedback pin on and off if it exceeds the threshold. Set by the current knob.  The LEDs surrounding the current knob work off sensing the current and using comparators to show the current in increments of 10mA.  

    (Status: Layout Designed).

    ----------------------------------------------------------------------------------------------------------------------------

    Prototype 2A was designed to integrate a negative rail for Op-amp usage.  Since this is for a more advance engineer with more demanding and accurate requirements we decided to implement a OLED display to display the voltage.  At the moment we have only done a layout and have not tested the negative rail.  This circuit is to be entirely analog with the display only providing voltage and current feedback. 

    (Status: Layout Designed)

    ----------------------------------------------------------------------------------------------------------------------------

    Prototype 3A was designed to be the most advanced and accurate.  It uses a single IC to boost and invert to +-13V.  This is then past through specialized LDO’s that can be adjusted down to 0V.  This method is costly but provides the best performance of all the prototypes.  Like all models the power is accomplished with complete analog and the Samd21 only does sensing and displays the data on the 0.96in Color TFT.  The reason keeping it analog is stability.  We do not want a code error compromising the output.

      (Status: Complete and tested)

    ----------------------------------------------------------------------------------------------------------------------------

    Prototype 3B Was designed to make the correction in 3A.  In addition to the +-Rails  are analog and digital inputs that can be utilized by the user.  2 Analog inputs and 4 Digital inputs.  Analog output DAC can also be used to provide small signals for testing. 

    (Status: Currently being Fabricated)

    ----------------------------------------------------------------------------------------------------------------------------

    Prototype 3C is the moonshot.  The Screen is upgraded to a 1.3” IPS to provide a larger viewing area.  Because of the larger display a SAMD51 is used to keep a stable refresh rate.  This additional area can be utilized for a Crude Oscilloscope and or Logic analyzer

    (Status: Layout Designed)

    -----------------------------------------------------------------------------------------------------------------------------

    iii. How ready is this design be taken to market?

    Prototype 1A, 1B and 3A Have been Designed and are currently being tested.  At the moment Additional safety features are being tested including short Circuit, Overload, etc.  These will be read for market within the next month or so.  These will require sourcing and testing to get the cost down as low as possible.

    One of the biggest challenges with this will be sourcing parts and manufactures to keep the cost low.   Currently the entry model uses 5x LM339 Comparators.  Even in quantities of 5 is less than the cheapest MCU.  But there is a point where there are enough led and comparators that a simple MCU and OLED Makes Sense.  Prototype 2A will address this. Within a 2 month Development Prototype 1C, 2A and 3B will be Ready for market.

    Prototype 3C will require additional Assistance as it will need special libraries for the 1.3” display to provide fast enough refresh rate for real time O-scope.  This would require some Assembly level coding.  But once the code is available to everyone improvements in performance can be made by the User base and implemented in future releases.

    Working with Suppliers, PCB Fab and assembly labs will be a major focus of bringing OPEN Power to the Masses.

    ------------------------------------------------------------------------------------------------------------------------------

    iv. How complete is the project?

    The first few prototype are complete and work as intended.  The rest of the iterations will require fabrication and testing before release to the market.  With each Iteration design flaws and the User interface is refined for a more user friendly experience.

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Discussions

Dan Maloney wrote a day ago point

I see what you mean about the silk screen. Not bad, but not stunning, which it should be. 

Looking forward to more progress on this. Keep up the good work.

  Are you sure? yes | no

John Loeffler wrote a day ago point

Yes and some of the Pads do not have soldermask in between I was only able to get 1 board of 3 working.  From now on I will be using JLBPCB which came back fantastic.

  Are you sure? yes | no

Dan Maloney wrote a day ago point

Cool. Just keep the black on white - that's a really good look. Although I did recently see OSHPark offer some cool dark designs.

  Are you sure? yes | no

John Loeffler wrote a day ago point

I saw that,  A transparent Soldermask that lets you see the copper traces.  This is perfect for finding the errors in my boards.

  Are you sure? yes | no

John Loeffler wrote a day ago point

And you have to admit that is the perfect logo for this project

  Are you sure? yes | no

Nicolas Tremblay wrote 09/11/2019 at 13:43 point

WOW! I just found your project. Can't wait for it to be market ready. Sign me up for the first kit.

  Are you sure? yes | no

John Loeffler wrote 09/11/2019 at 15:37 point

Thanks,  I defiantly want to keep the Hardware, (Especially the Scope one ) open Source so people can contribute and make it as fast and user friendly as possible.

  Are you sure? yes | no

Robb wrote 09/07/2019 at 19:35 point

It would be cool if one of the models is beginner-friendly to build, using mostly through-hole soldering as opposed to surface-mount.

  Are you sure? yes | no

John Loeffler wrote 09/07/2019 at 23:31 point

Interesting Concept.  I did a little digging and the only component I cannot find would be the boost ic.  This one goes down to 0.6V most only go down to 1.5V.  Made some compromises could be made with a much larger footprint.

  Are you sure? yes | no

John Loeffler wrote 09/08/2019 at 21:50 point

Looking into it further and doing a brief layout that is a definite possibility.  I can use a boost but it will only be able to go down to 1.25V and the leds can only be 1V increments.  But very doable.  The USB will need to be a USB-TYPE B for easy soldering.  The last IC is the Lipo charger, and i don't have any great options right now.

  Are you sure? yes | no

Salamandar wrote 08/27/2019 at 12:53 point

Hi, I'm porting this project to KiCAD as it's much better than Altium on so many levels (ex-altium user here speaking), Linux-friendly and open source.
https://github.com/Salamandar/openpower

  Are you sure? yes | no

John Loeffler wrote 08/27/2019 at 13:04 point

I am already in the process of doing that.  Altium is just much better in terms of CAD and layout.  Once i have verified the boars i will release it on KiCAD

  Are you sure? yes | no

Salamandar wrote 08/27/2019 at 13:47 point

Oh, I've already finished the schematics ^^
Do you want some help on it ? I've some experience on kicad.

  Are you sure? yes | no

John Loeffler wrote 08/27/2019 at 14:14 point

At the moment we are implementing safety circuitry (overload,Short-circit) and then testing.  Our goal is to have a stable and safe platform tested before we release it.  This will be within the next week or so.  We could definitely use your help.  Send me a DM with your Email.

  Are you sure? yes | no

Martin wrote 08/19/2019 at 07:26 point

Why do you use a SEPIC converter for 5V? You power it from a LiIon battery (max. 4,2V) and even disconnect the output while charging from USB. A normal step -up would be sufficient, uses less components and has better efficiency.

  Are you sure? yes | no

John Loeffler wrote 08/19/2019 at 12:49 point

You are absolutely right i will have to change that.  At one pint i was thinking of putting in a Barrel jack for more power options and decided to take it out but didn't change the SEPIC back to a Boost.  Thank you.

  Are you sure? yes | no

Keith Olson wrote 05/03/2019 at 04:34 point

FWIW, Instead of a knob, using 8 jumpers would give you the ability to set 0.1v - 11.9v directly, by using (modified) binary addition.  The major would be set up as 1-2-4-4 (0 - 11) and the minor would be set up as 1-2-2-4 (0 - 9).  For example, a 3.3v setting could be 1100 1100, while a 7.5v could be [1101 1001].  Making one of the major jumpers 8 instead of 4 would allow going up to 16v, and additional major jumpers would allow for even higher voltages.  LED's wouldn't be needed, as the voltage would be visibly displayed.

Does that make sense?

  Are you sure? yes | no

John Loeffler wrote 08/19/2019 at 12:51 point

That does make sense for accuracy.  I do however prefer to have a continuously adjustable rail for testing some circuits.

  Are you sure? yes | no

Aiden Fang wrote 04/23/2019 at 01:19 point

Wow! Great job! The color scheme looks very attractive. What software did you use to make the drawing?

Thanks!

Aiden

  Are you sure? yes | no

Ubi de Feo wrote 04/21/2019 at 07:06 point

Lots of great work going on here :)

I mostly use breadboards with 6 columns per side, rather than 5, and most of these adapters are useless in this case.

Not long ago I was wondering if there'd be a way to make the power rails adaptable to multiple sizes.

Food for thought, I guess ;)

  Are you sure? yes | no

John Loeffler wrote 04/21/2019 at 10:10 point

do you have a picture I could use for reference?

  Are you sure? yes | no

Arsenijs wrote 04/20/2019 at 17:09 point

Consider using 4-resistor arrays, it might allow you to save a bunch of board space and simplify the BOM.

https://p.globalsources.com/IMAGES/PDT/BIG/251/B1064309251.jpg

  Are you sure? yes | no

John Loeffler wrote 04/20/2019 at 19:33 point

Thank you that is exactly what i need

  Are you sure? yes | no

John Loeffler wrote 08/23/2019 at 15:31 point

I have implemented these in my Prototype 1b Design will post Soon

  Are you sure? yes | no

Jan wrote 04/18/2019 at 20:21 point

Nice idea. The LED thing is a bit over the top though and occupies much board space! 4x LM339?!?!?!
I wonder how you want to route that thing, there is next to no space for traces in the current design. Using 4 layer boards might work though...

  Are you sure? yes | no

John Loeffler wrote 04/19/2019 at 01:16 point

It is routed on a 2layer.  I have gotten pretty good at routing manually over the years.  Check out my prototype 3 it uses an 0.96 color Toft display and has loads more features.

  Are you sure? yes | no

Lukas wrote 04/15/2019 at 08:48 point

Great idea, i need this for my breadboard.

  Are you sure? yes | no

testsubj wrote 04/11/2019 at 18:56 point

There's already some similar boards on Aliexpress that do this. I didn't look for an adjustable version, but the ones that only output 3.3/5 cost less than $1 shipped.

  Are you sure? yes | no

John Loeffler wrote 04/11/2019 at 18:59 point

I love those.  This is usb powered with Lipo backup, as well as continuously adjustable and 5v and 3.3v rails

  Are you sure? yes | no

Dan Maloney wrote 04/11/2019 at 15:12 point

Agreed - great idea. You should really enter this is the Hackaday Prize - this would make a great product!

  Are you sure? yes | no

John Loeffler wrote 04/11/2019 at 15:15 point

Thanks I will,  Check out my Prototype 3.  It has more bells and whistles.  This version is a simple non Micro controller version. Right now the cost of components is less than $4 in low quantity.

  Are you sure? yes | no

Lee Wilkins wrote 04/10/2019 at 20:37 point

Great idea!

  Are you sure? yes | no

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