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Electronics => Projects, Designs, and Technical Stuff => Topic started by: Matthew98 on February 20, 2017, 08:35:51 pm

Title: DS0150 - mini digital osciloscope improvements and how to improve more
Post by: Matthew98 on February 20, 2017, 08:35:51 pm
Hey, guys !
Today my DS0150 arrived. Its dirty cheap digital osciloskope (around 25 dollars) and I absolutely love it ! They left little space inside the case, so i improved it a bit :) Now its fully portable with its 700mah battery. The stepup converter is probably not the best for osciloscope, but it will have to do :) Here are some pics :
http://i.imgur.com/oWsUZUH.jpg (http://i.imgur.com/oWsUZUH.jpg)
http://i.imgur.com/dS03kF6.jpg (http://i.imgur.com/dS03kF6.jpg)
http://i.imgur.com/rWjwyI2.jpg (http://i.imgur.com/rWjwyI2.jpg)
http://i.imgur.com/lFgjT3n.jpg (http://i.imgur.com/lFgjT3n.jpg)
But i still get lots of static, that the scope did on clean source of power. The knob for adjusting the static didnt really do much, so i left it where it looked same both on top and bottom. I was thinking, if better brands of the electrolytic capacitors or replacing ceramic capacitors with better ones would help ? :)
Thanks for any suggestions.
http://i.imgur.com/6usEgOz.jpg (http://i.imgur.com/6usEgOz.jpg)

If you want to make this power managment for yourself, here is the part list i used :)
Now keep in mind, that TP4056 will charge the battery (Lion or Lipo) 1A by default. You have to change resistor value to reduce current. Charge a cell with max of 1C (1C is capacity it has eq. 600mAh cell - charge with 600mAh max, if not mentioned differently in datasheet of battery) Im including datasheet with chart for those values here : http://www.haoyuelectronics.com/Attachment/TP4056-modules/TP4056.pdf (http://www.haoyuelectronics.com/Attachment/TP4056-modules/TP4056.pdf)
Parts :
Tp4056 - I used one, that has battery protection circuit built in.   
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.XTp4056.TRS0&_nkw=Tp4056&_sacat=0 (http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.XTp4056.TRS0&_nkw=Tp4056&_sacat=0)

Stepup converter - Chep one will do (Mine is older version of MT3608, i guess. It was laying at shelve for some time), you need variable one, so you can set it to 9V at this case.
http://www.ebay.com/sch/i.html?_odkw=stepup+convertor&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xstepup+converter.TRS0&_nkw=stepup+converter&_sacat=0 (http://www.ebay.com/sch/i.html?_odkw=stepup+convertor&_osacat=0&_from=R40&_trksid=p2045573.m570.l1313.TR0.TRC0.H0.Xstepup+converter.TRS0&_nkw=stepup+converter&_sacat=0)
Lipo battery - I used 700mah one, but it bearly fits. It might get a few tries to get the one, that fits.
Switch- I did not really measured the current going into converter, but it will surely by under 1A, it might be even under 500mA :)
Filtration capacitor - I used 470uF Hope its doing something ... :) :) :)
And thats all, folks... really easy mod, thas is applyable to lots of projects. Go ahead and buy bunch of convertors and chargers :) :)

Allright, the step up converter does make a differance ... :)
Without :
http://i.imgur.com/7RVAC01.jpg (http://i.imgur.com/7RVAC01.jpg)
http://i.imgur.com/yQLgSib.jpg (http://i.imgur.com/yQLgSib.jpg)

With :
http://i.imgur.com/wNJFCku.jpg (http://i.imgur.com/wNJFCku.jpg)
http://i.imgur.com/RLyPz0g.jpg (http://i.imgur.com/RLyPz0g.jpg)
Any idea, how to eliminate that ? :)
Title: Re: DS0150 - mini digital osciloscope improvements and how to improve more
Post by: qu1ck on February 26, 2017, 08:05:16 am
I'm not sure you actually have an issue with step up module. In your first photo "without" you actually have higher Vpp noise levels than "with" the module.

Anyway if you want to try to reduce ripple try these 2 things:
1. Put a choke on output
2. Step up voltage to higher than 9v and put an LDO on output.
One or the other, or both should help with ripple, however you will always see noise on this scope, it's unavoidable.
Title: Re: DS0150 - mini digital osciloscope improvements and how to improve more
Post by: Matthew98 on February 26, 2017, 12:12:00 pm
Sorry, its my fault... :) The noise is higher of curse with the module... :)
Thanks ! :)