Welcome to a new InTheMail, the series that will touch both your passion for electronics and your bank account at the same time. We’re going to start with this pocket multimeter, it’s the MUSTOOL MT77, let’s get it out of the box. As you can see quite a small form factor, the multimeter is very thin and has this large screen to body ratio, let’s see if they included the batteries and yes the meter turns on, it runs on two CR2032 batteries but it seems they are included.
Month: August 2019
Voltlog #250 – Replacing Bad 4mm Banana Plugs With High Quality Hirschmann and Staubli
In this video I replace some of my old crappy 4mm banana connectors with some new Hirschmann and Staubli, high quality connectors. These should be more reliable and provide a low resistance connection between my test gear allowing me to pass high currents without any issue.
Voltlog #249 – Making Some USB Serial Converter Boards With CH340E (part 1)
Welcome to a new video, today I’m building a bunch of usb to serial converter boards because if you are into electronics and microcontrollers you will for sure need a bunch of usb to serial converters to connect your boards to a computer for example.
The idea for building these boards started when I found the CH340E converter chip on aliexpress, I like several things about this chip, it was small because it comes in MSOP10 package, it was cheap at about $0.40 a piece and it requires minimal external circuitry, in fact it only needs an external bypass cap.
Voltlog #248 – Atorch Q7 USB Meter/Load With QI Wireless Charging
So this load is built with 3 active pcb’s as well as a fourth passive one as a front panel. They are joined with these brass standoffs and I think the standoffs act as circuit paths as well because I see no wires between the different levels. In order to get the alignment right during assembly the designer of these pcbs, made these corners rounded while these ones are diagonally cut and you can see these features along an entire side. This is a neat solution overall because it saves cost and as long as the screws are tight these should provide adequate connection.
Voltlog #247 – InTheMail
Welcome to a new InTheMail, the series that will touch both your passion for electronics and your bank account at the same time. We’re going to start with this small module, at first when I ordered it I didn’t fully understood what it does but now after doing a bit of research for this mailbag it seems this is an immobiliser emulator for the VAG group. So am immobiliser is a security component of your car that will not let the ECU start the engine unless a certain key or token is present. And there might be valid reasons why you might need this emulator, for example if the immobiliser is broken, you can supposably cancel it and start the engine with this emulator or if you exchange the motor/ecu combo once again it might not be possible to use the old immobiliser and so an emulator will help.
It talks over a K-line interface which is something specific to the automotive domain but it’s basically a form of serial interface. At first I thought this was going to emulate some kind of can bus and I was planning to play with it by scanning the bus but now I realize this is useless for me.
Voltlog #246 – What if we install a heatsink on the TPS61088 boost module?
In the previous video where I took a closer look at the TPS61088, I did some measurements of the output noise but I also ran the module up to the maximum specified output power of 12V 2A. It was to be expected that the losses would turn into heat and just the small size of the board would not be enough to dissipate all that heat safely so the boost chip reached a toasty 150 degrees Celsius and inevitably went into thermal protection.
There were two questions that people mainly left in the comments of that video. First people were curious if this module would behave differently if a heatsink was installed and also some people thought about using this module in a fixed configuration, because if you remember there is a chip on this module that will switch the output voltage based on quick charge spec, depending on what the load is requesting through that protocol but people might just want a simple fixed output. To this I would add a third question of my own, what is the real efficiency figure of this module, at the maximum output.
Voltlog #245 – TPS61088 Boost Module Test (with QC3.0)
The real limitation for this small module to output the claimed 24W for longer periods of time is temperature. There is not enough thermal dissipation happening with this small pcb. Having a bigger pcb with more copper layers would help and it would probably allow this module to output continuously and prevent the TI controller chip from going into thermal overload. Even so I was impressed that running it into thermal protection several times did not do any damage the chip recovered on it’s own each time and no magic smoke escaped during these tests.
So all of this considered, this is probably one of the best dc-dc boost converter modules I got from China so far and I would recommend getting one of these if the specs meet your needs.