Bluetooth Telemetry Link

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Bluetooth Telemetry

This Bluetooth serial link is nothing new. I had it working on the existing setup to send data from the ReactorForge control board to the Processing visualization program. The HC-06 Bluetooth module enabled me to see the live telemetry coming from the ReactorForge. That helps you to understand what is going on and tweak parameters such as the PID settings.

Consolidation of Development Process

I’m excited to get the entire development process in one operating system. Before, I was bouncing between macOS, Windows in VMWare Fusion on the Mac, and a separate Windows machine. It’s a long story, but this was partly due to the Windows-only compiler I used at the time. Other shortcuts I made early in the process just to get things working enough to get the induction heater to Daniel’s shop also helped put me in that spot.

Problems Connecting to the HC-06 Bluetooth Module on Mac

Getting the HC-06 Bluetooth to Serial module working on macOS wasn’t hard, but I did have one issue. The HC-06 seemed to just disconnect randomly after a minute or two of being connected. Then when I would try to reconnect to it, the port would be busy. I knew it wasn’t busy or open using lsof | grep HC-06 or whatever your’s is named, Reactor-Link in my case.

I fired up Windows in VMware Fusion and paired the HC-06 Bluetooth module. Then I opened a connection to it using a terminal program. I also began a screen session (terminal) on the Mac side with a USB to serial adapter. The USB serial adapter was connected to the HC-06 Bluetooth module to monitor it (and send data from it).

Anyway, this worked fine, and the HC-06 Bluetooth module never lost connection on the Windows side. I did notice that on the Windows side, the HC-06 Bluetooth module asked me for asked me for the pin number during the pairing process, but it did not ask on the Mac side. I removed the device from on the Mac side in the Bluetooth manager and re-Paired it. To my annoyance and relief, this fixed the disconnecting issue. Maybe I changed the pin in the past since the last time it had been connected to the Mac.

Bluetooth on macOS

So this is the simple test setup. The photos say it all I think.

Bluetooth Telemetry

Bluetooth Telemetry

Bluetooth HC-06.pdf

Libraries, Drivers, Etc.

With that working, I’m going to work on the libraries now. I’m looking at whether or not to get the existing libraries working in the new environment or use new libraries.  I’m leaning toward new libraries because there are quite a few compiler warnings and even some errors from the old ones. I’ll have to update function names and setup code, but I’d prefer to start with something cleaner and updated. I’m pushing it all to GitHub as I go!

Addition Terminal Jargon

The astute reader might notice that I am using the /dev/tty.* version of the device rather than the /dev/cu.* version. So, what’s the difference? TTY devices are for calling into UNIX systems, whereas CU (Call-Up) devices are for calling out from them (e.g., modems). We want to call-out, so /dev/cu.* is the correct device to use.

The technical difference is that /dev/tty.* devices will wait (or listen) for DCD (data-carrier-detect) e.g., someone calling in, before responding. /dev/cu.* devices do not assert DCD, so they will always connect (respond or succeed) immediately. Since neither the HC-06 Bluetooth module or the USB to serial adapter support DCD it’s not an issue. Still, following best practice, you should use the correct port.

So why did I use the wrong one in the photos? I switched to /dev/tty.* when I was having the connection issue and just forgot to switch back before documenting it.

Mains Power Feed Complete

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Mains Power

This is the last mains power update for the ReactorForge Induction Heater. It will be the last because it’s complete! Here is how the last couple days of that process went.

Mains Power

I started by connecting the jumpers from the custom splice connector to the 60 Amp 240-volt dual pole breaker and ground bus. The photo shows green hooked to the neutral bus. I later moved this as I did not need to tap 120-volt like I thought I would have to since the ATX power supply runs on 240-volt now. (I just forgot, it’s been a while.)

Mains Power

And here is the 240-volt quick disconnect assembly installed and ready. I will print another version of the slide lock. The slides should be solid so the splice connectors are not accessible while the wires are disconnected.

Mains Power

Next, I prepared the 2 AWG mains power feeder lines. These will connect the splice block directly to the input of the ReactorForge.

Mains PowerMains Power

The splice block side has thick metal tabs that are double layered with heat-shrink tubing. These provide a high current, high durability connection to the screw terminal that will stand up to multiple connect/disconnect cycles.

Mains Power

The Induction Heater side has heavy duty lugs that will accept the terminal post. These are also insulated with double layers heat-shrink.

Mains Power

Bringing It All Together

And here you can see the feeder lines connected to the input of terminal posts on the back of the ReactorForge. I also ran a USB extension with a small hub for connecting the Atmel ISP programmer. I put the Bluetooth dongle here as well. It communicates with the mainboard to send/receive commands and system telemetry.

Mains PowerMains Power

I then installed a variac between the mains contactor and the inverter input filter.

Mains Power Variac

When software activates the contactor, 240 volts directly feeds the inverter typically. Since I have a decent amount of testing to do, I severed that connection and installed the variac to allow lower power testing.

Mains Power

I taped up the small areas where 240 volts was accessible in the front to avoid accidental contact or tools shorting things out. Getting my fingers across 240-volt mains power is not something I want to experience twice!

Mains Power VariacMains Power

On To The CODE!

That’s it for cooling and mains power connections. The next step is to get the programming environment set back up. I will turn things up as is and do some testing to make sure everything is still good. Once that is done I will get right to the next big task, I’ve decided to port the entire thing to Arduino. This won’t be too difficult since the code is already in C and I will be glad to get away from AVR Studio, to be honest. I made the choice to move to Arduino due to is massive use and rise in popularity over the last few years. Since this is an open source project I want to use a platform that people are familiar with. Let’s put industrial level induction heaters right up there with open source 3D printer firmware!