Tuesday, March 13, 2018

JBC T245 / C245 Iron tip controller

Here it is the major post for February...with some delay. Remember I'm trying to do at least 1 major project/post a month this year.

I've been building this for a while, here reading the thermocouple on the JBC tip and here painting the front panel. It took longer also since the LCD display ordered arrive dead (took the one from my long wave receiver) and had some or mistakes causing short-circuits and a blown MAX6675 module.

Before you go an replicate have a look on the advantage and disadvantage of this system :

* Good:
- Super fast from power on to melt solder compared to a "traditional" iron, this one takes about 5s excluding the boot process.
- Temperature control... if you really need, I build a lot of electronics without needing it.
- Very light tip
- Short distance from hand to tip.
- Multiple types of tips to chose from.
- JBC tip's from previous experience (standard iron) have a reasonable duration, this one... time will tell.
- Controller probably will work, with minor changes, for other temperature controlled iron's.

* Bad
- The system from JBC costs in excess of 400 Eur, it's hard to justify just for the hobby that amount. A good soldering Iron will cost 10x less and does the same job. This system costs half of it but still expensive.
- Proprietary hardware on the tips and with the price of just two tips you already buy a perfectly fine soldering iron, not even considering the tip holder.
- Tips will most likely have a shorter live due to low size causing thermal fatigue shortly.
- It overshoots easily with this type of control, anyhow if you consider the set temperature as the minimum then take that as a feature.


And during software troubleshooting:

The schematic was based on this from "Great Scott":

My schematic (approximately):
I used a 220/12+12 transformer, tip is powered by 24V AC (showing 15 on schematic).
Used also another display type (I2C), another Triac (MOC3021) and another opto-isolator (4N35).
Also for the supply I used the same transformer for the Iron and Zero crossing detector (4N35). The Arduino used a separate transformer with two regulators, one for the Arduino (7808 to vIn/vcc) itself and another for the MAX6675 and LCD display (7805 +5v) since the regulator for the Arduino was causing reset's if the MAX6675 was powered from Arduino 5v output.

Here's how fast is from power on to melting solder:
...around 5s since power is applied to the tip. I think the other Iron I have takes more than 2 minutes.

I ordered the T245-C with the foam handle and got a T245-A with plastic and foam on top. that is a good thing and that was exactly what I expected when ordering, look's JBC is adding an extra layer of isolation:

The plug on the panel is an Hirose RPC1-12RB-6P(71) with 2.5mm holes.
I only fixed with two bolts since I'm not very good at aligning holes and only have the hand drill.

The iron tip counterpart plug:

Here's connections and tip equivalent circuit:

The total cost of the project was around 215.00 Eur (full station "mimic" of the JBC one: JBC CD-2BE) including the estimated price of a normal iron stand (18 Eur). Still half of the vendor price if I had shopping around.

Will try in the future to test this controller with other similar function Irons.

The code will not be listed for the moment, it is a modified version of Scott's code with a different LCD (I2C).
The display function call in Scott's code had to me moved out of the zero crossing function since it would break I2C communication due to fast rate of interrupts. That caused me some delay until I could understand what was the situation of the display freezing. I placed the display call on the main loop updating every 0.2s.

Another problem I had was since I was doing the build according to my needs I tried to avoid separate power transformers for the iron and modules so caused a short after connecting the "-" of a bridge output to the actual tap of the AC on the transformer. This broke one rectifier bridge and also caused two diodes to fail in short circuit which then on the troubleshooting caused me a problem with a secondary short-circuit. That's what happen when you don't put on paper the changes made. The schematic on this page has that corrected.

To be done:
- More soldering/stability testing using the unit, I already did some soldering with it and so far so good.
- Code refinements on the display update part
- Filter some erroneous (over) temperature reading
- Test and implement the sleep function
- Test and implement the tip change function

Have fun!

Saturday, March 10, 2018

Insulated, Stackable Banana Plug - BU‐31104 - 4mm

Nothing major here, just some instruction on how the best way to solder this plugs in case anyone looking for the info.

I bough some for the power supply and multimeter and questioned myself if there was a data-sheet for the plugs. There is, link for the "data-sheet" at the end.

They are a little of pain to solder with lower wattage soldering iron due to big surface area.

For my multimeter I had to cut a little to fully enter the terminals.
The main advantage for this ones is that they are stackable, the disadvantage is that have to be soldered, in some sense it can be advantage (better contact).

For assembly just follow this:

..easy!In my case I preferred to solder to the metal body without going trough the hole.

Data-sheet here: https://www.mouser.com/ds/2/279/DS-BU-31104-0-533043.pdf

Sunday, February 18, 2018

Mini paint booth

Not much of electronics here. Needed to paint a front panel and it was raining outside (as always), so, devised a make shift paint booth in the bathroom since it has forced ventilation (important).

Self explanatory picture:

Nothing much than a bin bag so that you don't spray outside and catch all the paint particles. In the middle place the part to paint.
It might take a little more time to dry but at least it's not weather dependent.

Here's the front panel, out of the paint booth, for a project that hopefully will post soon....if I can sort some issues with the electronics part:

...as you can see I'm not much of a painter.

Hope it helps someone.

Have a nice week!

Saturday, February 10, 2018

RTL-SDR Dongle interference shield/filter

Happy New Year!
I'll try this year to post more project's, (at least one for each month) and some more simple ones in the middle, that including the failed experiments (I do have them).

Said so, here's, with some delay, the first post for this year!

I had the RTL-SDR USB dongle for some time working but wanted to box it up and placed together with the Raspberry Pi already boxed up.
In the process wanted to eliminate some of the noise it was receiving. Keep in mind that even with noise it was working acceptable (just wanted it mostly for ADS-B and possible AIS reception).

So, decided to do some simple filtering and placed it on a full metal box.

In order to know the filter/shielding was working correctly, that is, the design was improving reception I used the QspectrumAnalyser Linux software to get the signal data in a small band subset and then compare on the several stages during filtering/boxing.

The final result of the build is this:

The noise reduction part is by the end of the post.

Here's already with the Raspberry Pi:
And the live feed with a random piece of wire as inside house antenna:

During build:

After connecting to the Raspberry was getting USB disconnects but not if I used it on the Laptop, after twisting together the USB signals cable (green and white ones) it stopped doing the behavior.

And fully boxed:

Now the good part, the schematic for the filtering:
I was looking for ideas here and here , were not tested since I started building the above circuit and it worked first time, to be fair there's nothing that can go wrong with it.

Here the several stages of interference reduction:

1 - With Just a 100uH in series with the power positive:

 2 - With the output capacitor after the inductor, we can see a big reduction:

3 -Here's me holding the USB ground terminal to the box, I am the antenna!
4 -Then soldered the USB ground to the box
5 - With the full PI circuit, much better:
6 -With everything connected, except for the top lid of the box.
7 - Final signal levels with box fully closed:

Additionaly some experiments in logging data from the dump1090 software:

I'll probably do in the future a a small post on that.

In the mean time have a great 2018!

Sunday, December 31, 2017

Egg beater fix

Friday afternoon....going to prepare dinner, egg beater is needed.... it works first time and then stops...no bang.... after a days work troubleshooting I don't need more of it :)

There are only 3 possible faults for a mains powered device:

1 - No power
2 - Open circuit
3 - Short circuit

There was power and there was no short circuit, leaving the open circuit possibility, in fact it was immediately confirmed since no resistance was measured from the power terminals... I only hoped it had not been a short on the engine windings causing the open circuit.

I confess that opening was easier than closing in the end, mainly due to mechanical interlock of the eject mechanism.

Here's the fault....

..on the speed/on/off switch, since it rotates (the transparent plastic part, along with the center washer) the wire broke at the terminal (mechanical stress).
In the picture was already in place for soldering, should last another year or two.

And pictures in the process of finding it:

 ... Sabichi brand...at least the electric motor looks reasonably built.

Just looked their website (https://www.sabichi.co.uk/the-company), that's not bad since most brands are just a sticker:

 ".....with one mission – to bring fantastic quality homewares to our consumers in the UK at a great price. We haven’t looked back since...."

.....Marketing.... it just means: bring Chinesiun or Eurocrap lower grade devices, re-brand and sell for the highest possible price...
Anyhow, even in our hobby we are seeing the same...

Have a great 2018!

Friday, December 29, 2017

Bench power supply ( part I )

This is part I from the build of a small bench power supply.
It's going to be 3 supplies in 1, one from 3-19V (build bellow), a 5v USB output and a variable dual rail implementation of the LM317/337.
The first one, already finish, is using an LM723 implementation, nothing special, just picked the first schematic that seamed viable and built it.
This power supply it's just to avoid having to resort to the 13.8V one from the radio since it will be used for small circuits testing.

Here's the outcome (left size finished minus buttons and voltage display, latter on that):

The USB out (in the midle) it's going to be useful for testing Arduino projects without fear of frying the USB port on the computer, it's just a garden implementation of the LM7805 with two 100nF caps on the input and output.

The schematic that I used for the variable supply was the one bellow (from here):

I used a TIP3055 and TIP31 instead since I didn't had the specified ones, the 600 Ohm resistor was replaced with a 680 one.

Bellow a similar schematic with more comprehensive details of the current and voltage controls (from here):

Inside stays like this:
More details with the TIP3055 heathsink (piece of metal) in place:
and the view to the front panel back side:
The box used was one on sale on the local electronics shop and even include a transformer inside, the only downsize was that you had to build your own front panel, nothing some PCB and elbow grease would not sort out:

Not perfect but works. Bellow another picture during front panel build:
The switch most to the left enables or disables the output, handy if you see something smoking while testing and it cuts faster than the main power switch due to charge on the filtering capacitors.

Enjoy the weekend and see you probably next year!