Voltlog #150 – Quick Update

Welcome to a new voltlog, in this video I’m gonna give you guys a few updates on what’s going on. So I’ve been working on the bigclown review, I’ve built my project which is collecting data and I am visualizing the data with Grafana which is very nice but I’m gonna wait a few more days before I collect more data and then I’m going to release my review of the bigclown kit.

Voltlog #137 – Eachine EV100 Distortion Problem Fix

In this video I show you how to fix the EV100 distortion or gray line problem. The problem is caused by an internal ac coupling capacitor which should be of a higher value to decouple any dc voltage offset from the video signal. While some people report a gray line plus some distortions I was seeing a black spot on the left plus some distortions.

I used a 220uF B sized tantalum capacitor and it worked great. But you can use anything above 100uF, electrolytic, ceramic, tantalum, whatever you have around. The voltage rating doesn’t matter as much, anything above 3V is good.

Something like an electrolytic might be easier to solder because of the longer leads that can be bent into the required spot, it’s really up to you what type of capacitor to use in this fix. There is enough room inside to fit any type of capacitor.

Here are some links where you can get the capacitors and extra info:

Voltlog #131 – Measuring The Efficiency Of The Ruideng Kis3r33S DC-DC Converter

You might remember this small module from the previous InTheMail, this is the Ruideng dc-dc converter with a claimed efficiency of 95%. Now a figure of 95% efficiency is not unheard of these days, many dc-dc converters can achieve this with proper circuit design.

This particular model uses the MP2307 converter chip manufactured by Monolithic Power and if we take a look at their datasheet we can immediately see where they got the 95% efficiency figure they advertise.

If you own fancy equipment like a source/measure unit than one instrument can do all the measurements and data log the results as well but a source/measure is out of our budget so we will be using multimeters for this test.

Here are links where you can find the equipment used in this video:

Voltlog #128 – LM338 Constant Current Regulator Circuit

Welcome to a new voltlog, today we are building a very simple constant current regulator based on the LM338 linear regulator. This is a very robust and stable classical regulator that is being manufactured by many big names like ST and TI, it has quite a high output current  rating of 5A continuous, it even comes in a TO-3 can package but today we’re going to use a TO220 which is more commonly available.

To make a constant current regulator out of this, is very simple, the datasheet gives us the circuit we need to use and we only need a low value resistor to do that plus the optional input bypassing cap which is 0.1uF. We’re going to use this formula to calculate the value of the resistor, so the output current is equal to the Vref divided by the value of the resistor.

External references:


Voltlog #126 – How fast can you update an e-paper display?

Welcome to a new voltlog, today we are going to answer the question how fast can you update an e-paper display, is it suitable to display live updating values from a sensor for example? Some people asked these questions in the comments of previous videos so I am doing some tests to try and answer these questions.

Now there will be a big difference between trying to update the whole screen and trying to update just a small section. And that delay might also be related to how fast the processor can send the information to the display. So for example measuring the time passed between sending the first byte of data to the display and the last byte going out is not that relevant, it might just be a slow processor, and the display could accept data much faster.

Also in the case of an Arduino the ram size is very limited so a full buffer could not be implemented. This means sending of the data to the display is done inefficiently increasing the time it takes for a full update.

Link e-paper display black/white:

More resources below:

Voltlog #124 – Getting Started With E-Paper Display Module

In this video I’m gonna show you how to load a custom image on the e-paper display. Let’s see how easy it is to get started working with one of these e-paper display modules and an Arduino board.

Link e-paper display black/white:

More resources below:

Voltlog #114 – Aneng AN8008 Probably The Best $25 Multimeter

Today we are taking a look at the ANENG AN8008 multimeter. This product was sent to me by banggood.com free of charge for the purpose of this review. They also sent me an ESD mat, because I have two benches in here in only one of them had an ESD mat so I needed a second one.

There is also a newer model, the AN8009 which I also reviewed, you can read about it here.

Links for the products shown in this video are below:

  • Aneng AN8008 Multimeter Link
  • ESD Mat Link