Author: Bzzz

Chart of Electromagnetic Radiations – vectorized (#P5)

Hey – I never met you and this is crazy…but here’s my first piece, so help me maybe? (umm, I had to look this up, for sure)

When watching good ol’ Dave’s mailbags, number 940 to be precise (starting at the 9 minute mark), I was instantly hooked when he showed the gorgeous physics poster. Being a qualified physics nerd myself and obviously having too much free time, I had the idea of…vectorizing it. For the greater good, in that case, nerdgasms in posters beyond A0 size. (is there a format beyond ANSI F for you weird yankee letter format guys?) […]

3rd October 2017 8th October 2017 By Bzzz In 1 Comment

O’CELL 26650 LiFePO4 8S 3.3Ah battery pack with BMS (WHL #28)

Same thing again – but different manufacturer. That’s what you get when you clean up your new lab… ;)

I know, might be boring to see another battery pack with almost identical specs (3.3Ah instead of 3.2Ah), but trust me, this is like night and day – or like quality China and Wan Hung Lo.

Of course these two batteries were purchased at the same time for the same thing, and they cost around the same as well. But (spoiler!): These two units work fine.

Top view:

Nice shrink wrap, proper label (shout out to O’CELL and their caring but not nagging sales people). […]

24th September 2017 3rd October 2017 By Bzzz In 2 Comments

CY UC-022-0.9M USB 3.1 Type-C Female to USB 2.0 A Male Cable (90cm) (Rant #R1)

Oooh, look at that precious hellspawn!

“USB-C to USB 2.0 Data Cable for Macbook Tablet, Mobile Phone – Black” – capturing everything that is wrong with USB-C!

Sure, carrying over the perfectly fine USB 3.0 spec into USB 3.1 and calling it “Gen 1” (in contrast to “USB 3.1 Gen 2” that is double the speed) is a huge fuckup on its own. There’s no better way to screw up a customer by allowing manufacturers to call something USB 3.1 compliant (new! shiny!) when it’s just 3.0 with a new badge. […]

16th September 2017 11th September 2017 By Bzzz In No Comment

26650 LiFePO4 8S battery pack with BMS (WHL #27)

This weeks article is another by-product of the ADC testing (WHL #26) from last week. Could’ve packed in there, but I wanted to share some remarks on Chinese battery technology…

So first of all, this isn’t a piece of kit that I bought myself. After testing two 12V/2.2Ah lead batteries from work that were sitting unused on a shelf for five years, I needed another victim. Those quality Panasonic cells were flat as Kansas – the LC-R122R2PG datasheets recommends 8.6V cutoff voltage at 3C = 6.6A or 9.7V at 1C. Fully charged, they delivered 1C at 7V or 1.5C at 2.5V at full charge – slow 10.5V discharging to 0.1C cutoff and recharging didn’t help much. […]

10th September 2017 10th September 2017 By Bzzz In No Comment

16 Bit I2C ADS1115 Module ADC 4 channel with Pro Gain Amplifier RPi (WHL #26)

Meep. We finally have a new product review, after all that editorial, recap and electronic load rubbish ;)

Today’s item in the mail is an I²C ADC on a small PCB, running four channels (or two differential ones) with 16 bit precision. Sounds nice? Well, if it holds the claimed specs, it IS a nice product! I bought it in mid-June on AliExpress for 2.06 USD. Adafruit, by the way, charges 15 bucks for the exact same thing. Do I smell profit margin?

Here’s how it looks straight out of the ESD bag:

Backside is a tad boring (keep the VDD in mind):

(there’s a floating island on the GND plane, boo!) […]

3rd September 2017 3rd September 2017 By Bzzz In 2 Comments

A beefy electronic load (#P4F2)

Hello again!

I’ve been asked: What do you do with this electronic load thing? Well, I‘ve been using it as a battery torture device, what else could you do with a variable resistance device…

For a crude first step in actually testing my unit and also classifying a newly harvested set of deeply discharged 18650 cells, I slapped together some minimalistic Arduino program and hooked the thing up in parallel to the battery under test. The electronic load was set to 2 Amps with another battery, which was monitored by the Uni-T 203A current clamp. […]

27th August 2017 3rd September 2017 By Bzzz In No Comment

A beefy electronic load (#P4F1)

Well, that was a long week…actually, it was a fortnight ;)

Here we go!

(the alignment of images really sucks when placed near the header of the post – thanks WordPress!)

So this puppy was manufactured by my new friends over at OSH Park (ordinary order, no extras) and I think I hit the express jackpot. I registered on June 8th and submitted my files – three hours later (1 AM my time on Friday) I already got notice of the panel assignment. Maybe the small size of 54mm x 31mm (2.1″ by 1.2″ for the Yankees out there) just made a perfect fit on the remaining board size and they sent it straight to production ;) As OSH Park charges 5 dollars per square inch of board area (for three units!), […]

13th August 2017 19th August 2017 By Bzzz In 2 Comments

A beefy electronic load (#P4)

This is a ranty introduction to the electronic load project – photos, circuits and more will be available in part 2 next week!

So…I’ve been torturing power supplies (and to a lesser extend: batteries) for ages. Usually to check their health status by comparing the current peak performance to the claimed values in the datasheet. Once you see voltage rails dropping where they should not, it’s time for a replacement of the unit, or in case of specialized PSUs, for a swap of the electrolytic caps.

But the crudity of my testing always bothered me – hooking up power resistors, measuring voltage and current, manually connecting and disconnecting the DUT, never hitting exact performance figures because of the limited selection of torture devices I had around. […]

30th July 2017 31st July 2017 By Bzzz In No Comment

Lenovo Thinkpad R400 LED Display backlight fix (#P3)

Yes, it’s running in the “projects” category, as “quick and dirty weekend fixes” isn’t available yet :mrgreen:

While I was hosting my brother, he casually asked me when I will fix his display. Umm…what?
Turns out, his Lenovo R400 was showing vertical stripes again. Like these:

(jup, stolen from some Apple customer help page – I didn’t take a photo at the time. I guess the bug is a watermark, isn’t it?)

Update from 23rd of December in 2020: By pure luck, I found this one from the previous issue while shovelling old photos and other data onto my server. […]

23rd July 2017 23rd December 2020 By Bzzz In No Comment

Back! Well, sort of… (#E4)

Hey folks, I’m back! ;)
Two months off the blog seemed like a long time, but actually it wasn’t. After filing taxes and hosting my brother for a week, I also got snail mail from the long-forgotten dispute with the German propaganda agency “ARD ZDF Deutschlandradio Beitragsservice”, formerly known as GEZ. And as they finally decided (after 1.5 years!) that they don’t care about my arguments and they also snooped my new address from the registration office, they let me know. I had the choice between accepting paying 18€ A MONTH for one-sided fake news that I don’t listen to (not even having a TV or radio to do so) or to start a pointless legal battle – so I went to court to just do that. […]

14th July 2017 17th September 2017 By Bzzz In No Comment