PS2-TTLserial adapter for RC2014 and MIDI

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Dr. Scott M. Baker published a new build:

The original reason for this project is that I wanted to build a standalone RC2014 with keyboard and display. There is an official RC2014 serial keyboard, but I find it a little inconvenient for my big fingers and poor eyesight. I have plenty of old PS/2 keyboards laying around, so I figured I’d rig up a microcontroller to convert the PS/2 keyboard interface into a TTL-level serial interface that could be plugged directly into the RC2014’s serial port.
Along the way, I discovered that the very same circuit would make an interesting project to turn a PS/2 keyboard into a simple MIDI controller. So I adapted the circuit for that purpose as well.

See the full post on his blog.

Check out the video after the break.

Vintage MIDI: Roland MT-32, Roland SC-55, HardMPU, and an Xi 8088

Dr. Scott Baker writes:

In this video, I decided to upgrade my home built PC from AdLib sound to MIDI. I tried out a couple different midi modules, the Roland MT-32 and the Roland SC-55. I learned that I’d need an MPU-401 or compatible ISA interface, and I explored the alternatives, eventually settling on the HardMPU by Ab0tj. Using the HardMPU schematic, I built a board, programmed the microcontroller, and tried out Vintage games on my Xi 8088. I also wrote my own Midi player to play .MID files using MPU-401 intelligent mode.

See the full post on his blog.

Modifying a computer ATX power supply for higher output voltage

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Kerry Wong wrote a post on his blog showing how he modified the 12V rail of a TL494 based ATX power supply to 14.6V for 4S LiFePO4 battery charging:

To charge the 110Ah battery bank I built, I need a power supply that can provide at least 10A at 14.6V. Since I have many old ATX power supplies lying around and the 12V rails of these power supplies are more than capable of providing 10A, I decided to modify one such power supply for using as a 4S LiFePO4 battery charger.

More details at his blog here.

Check out the video after the break.

TS100 oscilloscope hack

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Befinitiv wrote an article describing his modification to turn a TS100 soldering iron into an oscilloscope:

As you can see in the video, you can use the soldering tip as your measurement probe. Coincidentally, a soldering iron has already a pretty good form factor for an oscilloscope. Here is a still picture of a UART waveform

See the full post on his blog.

Check out the video after the break.

Halogen floodlight SMT reflow

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David Sanz Kirbis built his own reflow device with an halogen floodlight, that is available on Github:

First test was to check the speed of the temperature rise inside a standard halogen floodlight. Reflow soldering temperature curves are quite demanding, and some adapted ovens can’t reach the degrees-per-second speed of the ramp-up stages of these curves.
I bought the spotlight, put an aluminium sheet covering the inside surface of the protective glass (to reduce heat loss), and measured the temperature rise with a multimeter’s thermometer…. and wow! More than 5ºC/s… and I better turned the thing off after reaching 300ºC and still rising quickly.
So the floodlight was able to fulfill the needs.
Next step was a temperature controller, that is, the device that keeps the temperature as in a specified reflow curve profile in each moment.

See the full post and more details on his blog, TheRandomLab.

Check out the video after the break.

Pulsecounting and deepsleep based IoT water meter

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Tisham Dhar has written an article detailing his pulsecounting and deepsleep based IoT water meter project:

I admit to being a tiny bit obsessed with monitoring utility bills and gathering data on my usage patterns blow-by-blow. The energy monitoring has reduced my electricity bills, so I wanted to have a go at the water usage. Granted a lot of the water bill is fixed supply costs and sewerage charges which I can’t do much about.
A while ago I made some pulse counting breakouts with the DS1682+ RTC. I have finally got a chance to put them to good use interfacing with my mechanical water meter. The water meter has a spinning permanent magnet and in principle this can trigger a reed switch and generate pulses for accumulation by the RTC.

More details at Tisham Dhar’s blog.

Analog Discovery USB isolation

 

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Bob writes:

Back when I was deverloping the PSU burner, I wanted to have the Analog Discovery isolated from the common ground, to avoid noise and other issues. Since I did not have a way to do this, I ended up using a laptop on battery for measurements. But for long term, I needed to have this isolation. Unfortunately, things that can isolate USB at 480Mbps or faster are too expensive to justify.
The solution
The ADUM3160 isolator can provide a magnetically isolated 12 Mbps connection, which proved to be good enough. I grabbed one ready made isolator module from ebay for about $12, cheap enough. Well, it is not perfect: the B0505S DC/DC converter provided can only supply 1W and the Analog Discovery is a hungry beast.

More info at Electrobob.com.

Hacking the DPS5005

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Johan Kanflo’s OpenDPS project, a free firmware replacement for the DPS5005:

This write up of the OpenDPS project is divided into three parts. Part one (this one) covers reverse engineering the stock firmware and could be of interest for those looking at reverse engineering STM32 devices in general. Part two covers the design of OpenDPS, the name given to the open DPS5005 firmware. Part three covers the upgrade process of stock DPS:es and connecting these to the world. If you only want to upgrade your DPS you may skip directly to part three.

More details at Johan Kanflo’s blog.