Andy's Workshop Forums

General Category => Hardware projects => Topic started by: Andy Brown on July 12, 2015, 03:53:12 am

Title: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on July 12, 2015, 03:53:12 am
I've just posted a new article (http://andybrown.me.uk/wk/2015/07/12/awreflow2) in which I document the build process for a new reflow controller that uses an android app to communicate using bluetooth with the controller. The board is designed to be simple to build using (nearly) all through-hole components.

(http://andybrown.me.uk/wk/wp-content/images/awreflow2/pcb_built_small.jpg)

As usual all the gerbers (http://andybrown.me.uk/wk/2015/07/12/awreflow2/index.php/downloads) and firmware source (https://github.com/andysworkshop/awreflow2) are made available for people that want to build their own and there's a lengthy how-to-build video (https://www.youtube.com/watch?v=1ExZUTiHOVY) that accompanies it.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Alan Carvalho de Assis on July 19, 2015, 07:10:18 am
Hi Andy,
How are you, I hope fine.

I finished my project, but I decided to use TI DP83848 RMII instead instead of Micrel KSZ8081, see here:
https://farm8.staticflickr.com/7719/17107178730_346e67d0f7_b.jpg

You Oven Reflow project is very interesting.
I will try to replicate your reflow project and will let you know if it worked at 110V.

BR,

Alan
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on July 19, 2015, 09:31:46 am
Quote from: Alan Carvalho de Assis on July 19, 2015, 07:10:18 am
Hi Andy,
How are you, I hope fine.

I finished my project, but I decided to use TI DP83848 RMII instead instead of Micrel KSZ8081, see here:
https://farm8.staticflickr.com/7719/17107178730_346e67d0f7_b.jpg

You Oven Reflow project is very interesting.
I will try to replicate your reflow project and will let you know if it worked at 110V.

BR,

Alan


Hi Alan, congrats on finishing your project. The board looks well laid out, neat and tidy, and you've got the MCU and some other peripherals on there too so I'm guessing this is a complete project and not just a breakout board?
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Alan Carvalho de Assis on July 19, 2015, 07:57:43 pm
Hi Andy,

Yes, this is a board for a dog feeder project I was doing.

I got this board running NuttX with webserver an CGI support.

BR,

Alan
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on July 26, 2015, 10:54:19 am
If you haven't already seen the updates in the blog article then please do take a look. I resolved all the issues I was having with oven insulation, fixed a few bugs and tuned my PID parameters. My oven now tracks the reflow profile very accurately indeed.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: D.J. on September 27, 2015, 04:35:36 pm
Hi all,
I have just populated one of Andys boards - nice and easy :)
I haven't yet coupled up the 240V, but do have the board running at 6V and communicating with my tablet.

I have had some issues, which I would like to document here - so that other builders can be aware and see my solutions.
Most of these issues are outwith Andys control.

1) The HC-06 module that I bought did not name itself "HC-06" but "IDTech\r". This causes the Android app to fail to link.
The solution I used was to change the string"HC-06" to "IDTech\r" in the java source code and to rebuild the app.
ReFlowApplication.java
protected static final String OVEN_DEVICE_NAME = "IDTech\r";


2) The Nokia display that I purchased had a different arrangement for the LED backlight. Mine had the LEDs wired to Gnd, so required current to be injected into the "LED" pin (pin 7).
Solution I used was to remove Q3, R12 and R13. Fit a 100R resistor between PWM and P8.7 ( the pads for R12 and R13 can be used)

3) I suspect that the values documented for the AVR fuses are incorrect.
avrdude -c usbasp -p m8 -e -U lfuse:w:0xD2:m -U lfuse:w:0xff:m -U hfuse:w:0xd9:m
My analysis of 0xD2 for the low byte decodes as an 2MHz RC oscillator, whereas we have an 8MHz crystal fitted.
Solution I used was to use 0xFF for the low fuses.

4) The layout of P6 is not the same as the 6 way ISP connector on the ATMEL dragon, or the ATMEL AVRISP mkII so do not use a ribbon cable with 6 way headers with these programmers.
Solution I used was ribbon cable with 6way header at one end but individual headers at the other.

5) Be aware that there is no solder resist between the pads for the transistors, It is much easier to get solder bridges on these devices, Inspect carefully after soldering.

All I need to do now is persuade the Financial controller that we NEED a new toaster :) Then I can start cooking.

Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on September 28, 2015, 01:24:23 pm
Quote from: D.J. on September 27, 2015, 04:35:36 pm
1) The HC-06 module that I bought did not name itself "HC-06" but "IDTech\r". This causes the Android app to fail to link.
The solution I used was to change the string"HC-06" to "IDTech\r" in the java source code and to rebuild the app.
ReFlowApplication.java
protected static final String OVEN_DEVICE_NAME = "IDTech\r";


Ah, I mistakenly assumed that all those clones out there would be using the same firmware as each other. I guess not. It's an easy change for me to add the bluetooth device name to the app settings and I will do that because not everyone will be comfortable setting up an Android development environment.

Quote
2) The Nokia display that I purchased had a different arrangement for the LED backlight. Mine had the LEDs wired to Gnd, so required current to be injected into the "LED" pin (pin 7).
Solution I used was to remove Q3, R12 and R13. Fit a 100R resistor between PWM and P8.7 ( the pads for R12 and R13 can be used)


Thanks for documenting this workaround. It'd be slightly more complicated to add a high-side PNP switching circuit to control this arrangement but I could probably fit the component footprints on the board so people could choose whichever one suits their LCD.

Quote
3) I suspect that the values documented for the AVR fuses are incorrect.
avrdude -c usbasp -p m8 -e -U lfuse:w:0xD2:m -U lfuse:w:0xff:m -U hfuse:w:0xd9:m
My analysis of 0xD2 for the low byte decodes as an 2MHz RC oscillator, whereas we have an 8MHz crystal fitted.
Solution I used was to use 0xFF for the low fuses.


You're right. There's a bug in my programming script:


fuse_cmd="avrdude -c usbasp -p m8 -e -U lfuse:w:0xD2:m -U lfuse:w:0xff:m -U hfuse:w:0xd9:m"


As you can see I'm mistakenly repeating the value for lfuse but luckily the second value takes precedence and so the value I actually program is correct.

Quote
4) The layout of P6 is not the same as the 6 way ISP connector on the ATMEL dragon, or the ATMEL AVRISP mkII so do not use a ribbon cable with 6 way headers with these programmers.
Solution I used was ribbon cable with 6way header at one end but individual headers at the other.


There's always one thing you wish you'd done differently after you've submitted the PCB design for manufacturing and this was the one. If I do a rev.2 of the board then I will certainly be re-arranging those pins.

Quote
5) Be aware that there is no solder resist between the pads for the transistors, It is much easier to get solder bridges on these devices, Inspect carefully after soldering.

I mentioned this in the video. The pads are surprisingly close together considering this is a standard TO-92 footprint in Altium Designer. It's OK though as long as you're careful with the iron.

Quote
All I need to do now is persuade the Financial controller that we NEED a new toaster :) Then I can start cooking.


I highly recommend the halogen ovens that you can get for £30 on ebay. I can't believe that a traditional toaster oven would get anywhere close to the performance of the halogen ovens.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: bazc on February 11, 2016, 03:48:36 am
Quote
I now have a working power output that seems to follow and track a profile, the output is now nudging up correctly - so it seems to be a Bluetooth or android problem.


Good that it's following a profile, but there's something not right (see below code excerpt).

Quote
A few points noted when using display and switch operation:
1]   The oven will now reflow without manually preventing large overshoots; however the profile    seems to be different. I have no separate temp logging so cannot show you results but here    are so figures from display:

   0    to    90  secs   ramps up to 115c
   90    to    180 secs    holds at 115c
   180    to    216 secs    ramps to 195c
   216    to    240 secs   reflow with 220c max.

2]   Is the manual profile same as android use?

Yes, the same as the linear profile.

Quote
3]   Does the manual use default to Linear?

Linear is the only option for the embedded profile due to available space on the ATMega8. From ReflowRegion.cpp, values are { time, temperature }:


  const ReflowRegion LeadReflowRegions[6] PROGMEM = {
    { 90,150  },      // preheat
    { 180,180 },      // soak
    { 200,210 },      // ramp up
    { 220,210 },      // reflow
    { 240,180 },      // ramp down
    { 270,25  }       // cool down
  };


It seems clear that either the display is not updating correctly or the algorithm isn't tracking the embedded profile. I will investigate this.

Quote
4]   There is no spline / linear selection using enc swich.

Correct (see above)

Quote
5]   When time display reaches 3 figures, demand temp display is over written.

Definitely a display bug. I'll take a look at that. The embedded profile hasn't seen nearly as much work as the Android interface as it's only really a fallback in the case of problems like those you are seeing with Android.

Quote
Using PID setting 10,1,0  the controller now tracks the displayed demand temp within a deg or so.

Sounds good. The best values for your setup will depend on your oven, insulation etc.

Quote
Many thanks for a great design, any comments would be great.


Aside from the issues you've found in the embedded profile, I'd like to continue to try to help get to the bottom of the Android problems that you're seeing. One thing that I can do is to slow down the update rate in case what I'm using is too fast for you. Currently the app will poll for the last temperature reading and/or set a new target temperature every 300ms and the firmware will poll the sensor for a new reading every 200ms. I will relax those two settings and produce a test build for you to try at the weekend.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on February 13, 2016, 04:31:58 am
Quote
A few points noted when using display and switch operation:
1]   The oven will now reflow without manually preventing large overshoots; however the profile    seems to be different. I have no separate temp logging so cannot show you results but here    are so figures from display:

   0    to    90  secs   ramps up to 115c
   90    to    180 secs    holds at 115c
   180    to    216 secs    ramps to 195c
   216    to    240 secs   reflow with 220c max.


This is now fixed and pushed to github (see issue #1 (https://github.com/andysworkshop/awreflow2/issues/1))

Quote
5]   When time display reaches 3 figures, demand temp display is over written.


I cannot reproduce this. When I tested it while fixing the tracking issue the status line at the bottom of the display was always correctly formatted.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on February 13, 2016, 04:41:20 am
Quote
One thing that I can do is to slow down the update rate in case what I'm using is too fast for you. Currently the app will poll for the last temperature reading and/or set a new target temperature every 300ms and the firmware will poll the sensor for a new reading every 200ms. I will relax those two settings and produce a test build for you to try at the weekend.


I've generated an android app with the polling rate reduced to 1000ms. You can download it here (https://drive.google.com/uc?export=download&id=0B9Zobp2aWUKzWFE2WjBSbHZWckE). It can be side-loaded on to an android device. I'd be interested to know if this helps you.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: bazc on February 14, 2016, 10:10:22 am
amended HEX file loaded and now works great ! also formatted bottom line temp no longer overlapping.
I will try the android app next
many thanks Barry
Title: Re: An easy to build android/bluetooth reflow controller
Post by: bazc on February 14, 2016, 11:56:48 am
awreflow2-1s-update.apk side loaded into my android which is a IRULU x7.
not much different Andy, so maybe next I will get a replacement HC06 to make sure its not faulty.
I have attached photo of best run.
regards Barry
Title: Re: An easy to build android/bluetooth reflow controller
Post by: bazc on February 17, 2016, 10:52:58 am
I have fitted another Bluetooth HC06 from a different supplier.
Android control is the same, so not the Bluetooth unit.
I will try a android phone but cant do that until my girlfriend arrives next week.
in the meantime I will tyry to video operation so you can see what happens.

Barry
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on February 17, 2016, 02:29:38 pm
Let's wait and see if it's OK with the Android phone. I've used it with the Irulu X1s (that's the cheap one in the photograph in the article), a Nexus 10, a Samsung S4 and an HTC One M8.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on February 20, 2016, 03:39:15 am
Barry, I've created a new release of both the app and the ATMega8L firmware. You should get an update notification from Google shortly that will prompt you to upgrade. A few minor bugs are fixed that may not be relevant to your specific issue but you should take the update anyway. If you can't wait for google then the .apk in github is the new version.

The ATMega8L firmware is pushed to github and available now. The major change is that the firmware will now continually display the oven duty cycle whilst the android app is connected. This means that you can run a reflow from the app and compare the duty cycle displayed in the app with that displayed by the firmware. The values should be almost in sync with the firmware lagging by about half a second.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: bazc on February 26, 2016, 02:24:04 pm
Great work Andy, now works a treat with my tablet !

FYI - I did try with a an android phone before the update firmware and it did work, I suspect it loaded the updated app so cant tell you if it would have worked with the earlier version.

I now have a fully working oven which I can thoroughly recommend to anyone.

what would be nice if you can do it, a spare output on ATMega8L to go high when cooling stage starts. I want to try drive a cooling fan.

Barry
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on February 27, 2016, 01:37:57 am
Quote
Great work Andy, now works a treat with my tablet !


Great news Barry and thanks a lot for working with me to get this sorted out.

Quote
what would be nice if you can do it, a spare output on ATMega8L to go high when cooling stage starts. I want to try drive a cooling fan.


Interesting... due to flash space issues it would have to be a single GPIO that goes high during the final reflow stage (the cool down). Pins 6 and 26 are currently available for use.

Looking to the future,  I think I'll be doing a 'version 2' board at some point that will include an extra transformer footprint for US users on a 120VAC supply. I'll also upgrade the MCU to the venerable 328p seen in the Arduino Uno which will give me more flash space to include a PWM fan output that would be driven at a duty cycle matching the degree of cooling required. That won't be until much later this year though.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Glen on March 25, 2016, 09:51:26 am
Hi Andy,

Loving the site, well done :)

I'm going to have a go at the bluetooth reflow oven, however on uploading the gerber files to dirtypcb, I get the following error

No board outline (GML/GBR/GKO) file: you should include the board outline on a layer with one of these file extensions. This is done through the CAM processor of your CAD program.

I've already paid for the order, and I don't have access to any software that would allow me to add a board outline. Can you add a board outline to the zip?

Cheers

Glen.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on March 25, 2016, 11:35:21 am
Hi Glen,

The board outline is actually included on all layers but it looks like their software specifically requires it to be included separately on a mechanical layer. I've attached it on the GML layer. If you want to verify that it's correct then simply load it up into a Gerber viewer along with the other layers and they should all be aligned correctly.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Glen on March 26, 2016, 10:05:25 am
Hi Andy,

Thanks for that. Once I included that file, the site accepted the gerber files without any problems.

Cheers

Glen.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: JohnBurton on April 10, 2016, 10:29:34 am
Hello,
I'm building myself a similar project and I'm in the testing phase.
I am reading a thermocouple on my microcontroller and it seems to work once I figured out the SPI settings.
The temperatures look plausible.

However I find that the thermocouple takes a very long time to cool down.
Even if I remove it from the oven it seems to only cool at the rate of one degree every few seconds, taking maybe 3 minutes to cool from 150 degrees to 50.
Does this seem normal?
Title: Re: An easy to build android/bluetooth reflow controller
Post by: JohnBurton on April 13, 2016, 03:13:11 am
I found what the problem was, I had connected up the thermocouple chip to my microcontroller wrongly. Frankly I don't understand how it was working at all.

I'm finding that I have to turn the oven on and off fairly frequently to maintain accurate temperature control. For example making a decision to turn it on or off every second.  I worry that the fan and heater are going to be damaged by doing this several hundred times over the space of making a single PCB.
Has this been a problem?

Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on April 13, 2016, 01:35:02 pm
Quote from: JohnBurton on April 13, 2016, 03:13:11 am
I found what the problem was, I had connected up the thermocouple chip to my microcontroller wrongly. Frankly I don't understand how it was working at all.

I'm finding that I have to turn the oven on and off fairly frequently to maintain accurate temperature control. For example making a decision to turn it on or off every second.  I worry that the fan and heater are going to be damaged by doing this several hundred times over the space of making a single PCB.
Has this been a problem?


Hi John, my controller can adjust the duty cycle to a new percentage at an interval of 300ms. Are you pulsing on/off instead of dimming with a triac? You get much better control with dimming and the higher update frequency helps keep it on track with small nudges in the right direction.

Title: Re: An easy to build android/bluetooth reflow controller
Post by: JohnBurton on April 14, 2016, 01:32:24 am
Well, I already had a solid state relay so I've used an incredibly cheap stm32f prototype board and a themocouple input module and a bluetooth module to hack together a controller and a breadboard. It's amazing what you can do with about 4 parts :P
I guess it's inspired by your first reflow project although I'm using a bluetooth module to control it like your second because it's such a easy way to interface to a project now :)

I'm doing some very basic PID control to work out the 'strength' of the heat needed at any given time and then each 6 seconds turning on the heater for 1-6 seconds depending on the strength required. The temperature fluctuates a bit but seems to remain within a few degrees of my target overall.

I've made a few simple SMD boards with just some 0805 leds and resistors on as a test and they seem to have worked perfectly :P

I don't like turning the heater on and off so often though, apart from the fact that it makes exact control impossible I'm sure it won't do the heater any good.

I guess my plan is to get the current breadboarded version working well enough that I can use it to build a more advanced second version. I'm lacking confidence in using mains power directly safely but I expect like anything else, I can carefully learn.

Thank you for your projects, as well as being useful to me directly, they have inspired me to do a lot more with my hobby than I might otherwise have done :)
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Glen on September 09, 2016, 12:55:07 pm
It would seem as though the BTA312-600B is now discontinued, would the BTB616-600SWRG work as an equivelent?

If not, any suggestions?

Cheers

Glen.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on September 11, 2016, 12:52:49 am
Quote from: Glen on September 09, 2016, 12:55:07 pm
It would seem as though the BTA312-600B is now discontinued, would the BTB616-600SWRG work as an equivelent?

If not, any suggestions?


Hi Glen, try the BTA12-600BWRG by ST Micro. It appears to be a direct replacement with the same 3Q triggering and current characteristics.

Google couldn't find the part number you quoted but I can guess from the code that it's a non-insulated (the tab is live) version with a more sensitive gate current (10mA). I prefer to use the insulated versions and while the 10mA gate variety will probably work I haven't tested it so couldn't say for sure.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: thailoz on January 29, 2017, 01:55:45 am
Hi thanks for an interesting project

I downloaded the pcb files and see that they are all surface mount components do you have the original Th design as at present i have no way of re-flowing smd and don't relish the thought of hand soldering them (read eyes not too good )

thanks

Laurence
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on January 29, 2017, 05:00:05 am
Quote from: thailoz on January 29, 2017, 01:55:45 am
Hi thanks for an interesting project

I downloaded the pcb files and see that they are all surface mount components do you have the original Th design as at present i have no way of re-flowing smd and don't relish the thought of hand soldering them (read eyes not too good )

thanks

Laurence


Hi Laurence, I think that you may have downloaded the gerbers for my earlier project (http://andybrown.me.uk/2014/05/11/awreflow/). Here's a direct link (https://drive.google.com/uc?export=download&id=0B9Zobp2aWUKzYWFCREV0SW1aU1k) to the gerbers for the android/bluetooth project.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: DeNew Lab on March 28, 2017, 03:38:11 pm
Thank you very much for the project Andy!

I have quartz heaters of 6 pieces 500 Watt = 3000 Watt
Instead of a triac and an optocoupler, you can connect a solid state relay (SSR-25DA maybe)



https://www.aliexpress.com/item/1-pc-SSR-25DA-Solid-State-Relay-Moudle-SSR-25-DA-25A-Hot-Sale-Quality-1/32767243749.html
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on March 30, 2017, 02:21:12 pm
You could try an SSR. As long as it can switch at the mains frequency and will automatically shut off at the zero crossing then it ought to work.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: DeNew Lab on March 30, 2017, 03:59:26 pm
Thank you.
I'll try later SSR.
SSR HSR-2D302R (no ZeroCross Switching)
Z - Zero Cross Switching
R - Random Switching


Quartz heaters did not like the long heating.

A new project, halogen lamps 10ps. of 1500W, consistently 2 pieces.
I bought a toaster oven ))
Title: Re: An easy to build android/bluetooth reflow controller
Post by: DeNew Lab on June 07, 2017, 06:21:51 am
The first check of the stove.
Thermoprofile is excellent.
The result. 12 lamps of 1500 watts. 3 connected in series.
Sorry for the mess ... :-[

https://www.youtube.com/watch?v=A_tCNhYqNXg&feature=youtu.be

Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on June 11, 2017, 12:51:59 pm
Your oven is super-accurate throughout the whole profile, better than I've ever achieved and I thought mine was good. I particularly like the way that yours heats from the top and bottom at the same time. Best reflow oven I've ever seen, well done!
Title: Re: An easy to build android/bluetooth reflow controller
Post by: davek on March 20, 2019, 08:51:18 am
Hi Andy,
Just wanted to check this topic was still live as there hasn't been any posts for a while 
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on March 20, 2019, 09:38:25 am
Hi Dave, yes I'm here. If you have any questions please ask.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: kellogs on May 30, 2019, 04:42:28 am
Hello,

Great project, just what I needed!

Is it supposed to start the heaters if commanded so from the rotary encoder ? It has never been linked to a bluetooth device and it is running off the internal 8Mhz RC for the moment.

Thank you
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on May 30, 2019, 06:57:06 am
Hi, yes it will do that. Bluetooth is not required to run a reflow.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: kellogs on May 30, 2019, 03:24:33 pm
Alright, I'll be needing some help please.

Checked with a DMM (steady 0V, no fluctuations) and the MCU is not driving the transistor -> optocoupler -> ultimately triac. Of the top of my head MCU should drive the triac if
- asked to do so from rot_enc;
- it has proper zero cross detection (checked with logic analyzer; it does)
- it has proper SPI comm and good type K thermocouple & wiring

The SPI is good (LCD is functional) + checked for continuity on all 3 wires (MAX31855 <-> MCU). Now about this thermocouple.... ebayer sold it to me as type K but from what I gather it should have had a magnetized cathode, which it does not - i.e. neither of it stwo wires will stick to a magnet. Maybe it ain't a K-type TC and that's what bothers the whole system ?
I seldom see any temperature on the LCD as the screen is covered by "Err 2 No link or similar, but I have seen 27, 0, and 55 degrees C on it, and I think nothing else. Checked with DMM for voltage and the the TC does respond with some milliVolts upon heating thoroughly and some 1-2 minutes latency (from time of heater switch off to actually seeing it decrease in voltage). Tomorrow I shall get my hands on a new TC, hopefully of K type and report back. If any hints please share,

Thank you!
Title: Re: An easy to build android/bluetooth reflow controller
Post by: kellogs on June 02, 2019, 06:48:38 am
I have now put in the 8 MHz crystal and got bluetooth working. Also got a second thermocouple; they both seem to have the same problem "gnd short". Checked for T+ / T- for shorts to GND; nothing came up. The resistance between T+ and T- I have found to be 11 ohm if it is of any importance. For brief moments there actually is a temperature reading on Android if I fiddle with the connector lugs. Most of the times I fiddle with them and still just "gnd short". Any clues ?

Thank you
Title: Re: An easy to build android/bluetooth reflow controller
Post by: kellogs on June 03, 2019, 11:53:57 am
Ok, fixed that one. It was an error in my electrical scheme. I have got temperature, what I haven't got is power on the oven terminals. Reflow session begins and 0V reads over those terminals. When I take out the oven wires from the oven PCB terminal block I can read 135 - 140V in or out of reflow session. The oven works fine when applying power directly over its wires, and the logic side driving the MOC3020 also appears to work (i.e. checked for voltage on the Q1's collector: it is 83 mV, so it is saturated). Now what ? ...
Title: Re: An easy to build android/bluetooth reflow controller
Post by: kellogs on June 04, 2019, 04:09:48 pm
Now just swap the connections between A1 and A2 pins of the triac and it will work. Not recommended though, I have ended up with these very close wire-to-pin cases. So it kind of works, aside from three times smoking, the strange noises, and huge initial latency my quartz oven has. It comes up to speed afterwards, I guess I'll have to tweak the PID. And the everything else.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: HDRW on June 24, 2019, 09:29:47 am
Hi Andy, I'm new here, having seen one of "your" reflow boards demonstrated at the Newbury Radio Rally yesterday.  Very impressive!
I'd like to have a go at building one, but at the moment I don't have the time (I'm retired, so have no time to spare!  :-)

I did notice one thing in the video, though:  it looks like you're using an IEC *input* (C14, plug) for the connection to the oven, when it should be an output (C13, socket) - otherwise you could have unshielded pins with live mains on.  Or is it an oprical illusion in the video?

73,

Howard  G1BYY
Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on June 25, 2019, 01:00:21 am
Hi Howard, yes you are right I used the wrong gender connector there and didn't warn others not to do the same.
Title: Re: An easy to build android/bluetooth reflow controller
Post by: _jp on August 02, 2019, 04:48:01 am
Hi Andy/Everyone

Thanks for posting so many articles, it really helps newbies like me getting started in electronics hardware projects.

I'm using KiCad and I can load up the the gerber files ok, but I would like to play with the schematic.
Is it permissible (or even possible) to get a copy of the reflow project so I can load the schematic into KiCad?

Also, I really like your process controller articles. Nice one.

JP

Title: Re: An easy to build android/bluetooth reflow controller
Post by: Andy Brown on August 05, 2019, 01:56:12 pm
Hi, I see that there's a script available that converts Altium to KiCad. I'll run it on the schematic at the weekend and if it works then I'll provide the results.