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41
Hardware projects / Re: An easy to build android/b...
Last post by kellogs - 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.
42
Hardware projects / Re: An easy to build android/b...
Last post by kellogs - 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 ? ...
43
Hardware projects / Re: An easy to build android/b...
Last post by kellogs - 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
44
Hardware projects / Re: An easy to build android/b...
Last post by kellogs - 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!
45
Hardware projects / Re: An easy to build android/b...
Last post by Andy Brown - May 30, 2019, 06:57:06 am
Hi, yes it will do that. Bluetooth is not required to run a reflow.
46
Hardware projects / Re: An easy to build android/b...
Last post by kellogs - 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
47
Hardware projects / Re: How to use a 4k TV as a co...
Last post by Phil - March 25, 2019, 01:24:04 pm
Glad to see you are back. I feel that there will be a new project to connect sleep function to the new monitor!
48
Hardware projects / How to use a 4k TV as a comput...
Last post by Andy Brown - March 24, 2019, 11:50:01 am
I just posted a new article that documents my experience using a 4k TV as a computer monitor. I walk through the selection process documenting all the pitfalls that I found along the way. Hopefully if any of you are considering doing the same then this will help you make your decisions.

Click here for the article.
49
Hardware projects / Frequency counter using FPGA
Last post by wafaem - March 22, 2019, 10:03:55 am
Hello everyone,

I'm currently working on a project that aims to build a frequency counter(reciprocal one);but since I don't come from an electronic background I really don't know how and what to do.
My aim in this project is the frequency since the signal is very fast, I'm using nexys 3, if anyone has an idea or worked before on this I will appreciate it.
thnk you
50
Hardware projects / Re: An easy to build android/b...
Last post by Andy Brown - March 20, 2019, 09:38:25 am
Hi Dave, yes I'm here. If you have any questions please ask.
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