Schematics and Circuit Board layout with Fusion 360

[mickeyf]

Great suggestions @Arbutus

But... 10 boards, 10 different people, does that mean 10 stencils, or pass one around? There may be 4 or 5 here on the Island that could share? If I get back into making electronics then a re-flow oven would definitely be a thing, but this may be a one-off for me, so hand soldering is probably it. Unless there's a simple hand solderable toaster oven controller project to recommend

And yes, larger SMDs unless there is a valid requirement for the smaller ones only makes sense.

 

[djberta]

Great suggestions @Arbutus

But... 10 boards, 10 different people, does that mean 10 stencils, or pass one around? There may be 4 or 5 here on the Island that could share? If I get back into making electronics then a re-flow oven would definitely be a thing, but this may be a one-off for me, so hand soldering is probably it. Unless there's a simple hand solderable toaster oven controller project to recommend

And yes, larger SMDs unless there is a valid requirement for the smaller ones only makes sense.

Stencils can be 3d printed pretty easily, they are not perfect but work. Hand soldering smd is not to bad just takes a bit of time and I personally use a cheap rework station from amazon works great. For a reflow oven, do a search for esp32 reflow oven build. I was looking at building one before we moved.

I like this one, I would definetly add a snap switch or two for over temp. Other then that this one looks pretty good.

GitHub - dukeduck1984/uReflowOven-Esp32-Micropython: μReflow Oven controller based on ESP32 with MicroPython & LVGL

μReflow Oven controller based on ESP32 with MicroPython & LVGL - dukeduck1984/uReflowOven-Esp32-Micropython

github.com

 

[jcdammeyer]

Stencils can be 3d printed pretty easily, they are not perfect but work. Hand soldering smd is not to bad just takes a bit of time and I personally use a cheap rework station from amazon works great. For a reflow oven, do a search for esp32 reflow oven build. I was looking at building one before we moved.

I like this one, I would definetly add a snap switch or two for over temp. Other then that this one looks pretty good.

GitHub - dukeduck1984/uReflowOven-Esp32-Micropython: μReflow Oven controller based on ESP32 with MicroPython & LVGL

μReflow Oven controller based on ESP32 with MicroPython & LVGL - dukeduck1984/uReflowOven-Esp32-Micropython

github.com

I was going to build the Adafruit version (on the 42 projects list). I used the Thermocouple module for my Compressor Exhaust Air and the other modules are reserved for the Kiln controller (also on the 42 projects list).
The instructions for the ESP32 version are rather sparse but I think doable.

 

[Tomc938]

Hey @djberta: I sent you a PM.

 

[slow-poke]

Regarding E117-01 (the updated PCB with differential input capability)

The manufacturing files are available for this board if/when someone is interested. IIRC someone was about to place a PCB order for an unrelated board, so adding this board to an existing order should incur very little cost perhaps $20? for 10 boards. One of these boards could then be populated by hand to verify everything is as it should be.

I would prefer to keep the files as not released to the wider population until proven. If interested please PM me.

 

[jcdammeyer]

Speaking of solder paste. Back in 2010/2011 places like PCBWAY didn't really exist and certainly stencils weren't provided as an extra.
My solution was going to be a solder paste dispenser on the JGRO CNC router and the Toaster Oven (I have two) for doing the boards. Maybe even use the JGRO CNC Router as a pick and place too.

All this discussion took me to a top shelf and I opened up a box from May 2011 for this product:
http://teliasia.com/dis.asp I have the 1200A model.
Although the link has videos they don't work.

Maybe one day I will finish the toaster oven reflow and the solder paste dispensing. Back in 2011 it cost me $152.80 US based on the paperwork in the box.

 

[mickeyf]

IIRC someone was about to place a PCB order for an unrelated board, so adding this board to an existing order should incur very little cost perhaps $20? for 10 boards. One of these boards could then be populated by hand to verify everything is as it should be.

Anyone pursuing this? I'd populate a board for testing, but at the moment none of my machines even have scales, so I have no simple way to test.

Where's the "Project Manager"?

 

[David]

I’m bowing out now thanks to @PaulL

 

[mickeyf]

It would be a shame for this to fall through the cracks after @slow-poke putting in that effort. So @David you now have a touch DRO from @PaulL, yes?

I saw these cheap ($30 each or "generous discount for box of 6" ) no-name Android tablets on market place (in Oak Bay) a couple of days ago, and have gotten some more information from the seller:

Facebook

www.facebook.com

Not mentioned in the ad, but he tells me:

"They will not support a newer version of Android (not out of the box) they do have Bluetooth and WIFI. And they are 10" wide by 7.5 tall. As for brand they are direct from a MFG in china so no brand name"

So they have the recommended - better than required - version of Android, a good size screen, are new in the box, and are much cheaper than a "brand name" tablet, especially if enough other people wanted one for a group buy 6-pack.

If one of the Victoria people who has Touch DRO up and running would be willing to confirm that these do work with it, I'd gamble on one for the testing, and especially if a test shows no incompatibilities or speed bumps that there is interest in a group buy to further reduce the cost.

"Speaking strictly for me" I would rather spend $30 or less than $100 upwards when possible.

 

[David]

Yes, I have Paul’s TouchDRO.
I have used TouchDRO with an Amazon Fire tablet. $20 used on Marketplace. Works great.

 

[djberta]

I am still interested in the project for 2 boards. Is it still moving forward?

I have 2 of the original boards from Tom for my rf30 mill and SM 9 lathe. I have to build them out yet. I would also like to put touch dro on my new to me emco lathe mill combo.

 

[slow-poke]

I am still interested in the project for 2 boards. Is it still moving forward?

I have 2 of the original boards from Tom for my rf30 mill and SM 9 lathe. I have to build them out yet. I would also like to put touch dro on my new to me emco lathe mill combo.

If someone wants to order a batch of the new board, I can provide the mfg. files. The new board has less components and differential inputs.

 

[mickeyf]

Does the new board have SMDs of a size that would be, um, "challenging" to hand solder, or did the latest design bump up the size of those?
Or

If someone wants to order a batch of the new board

...perhaps they will look into having it populated with the SMDs, but not the large connectors?

 

[slow-poke]

Does the new board have SMDs of a size that would be, um, "challenging" to hand solder, or did the latest design bump up the size of those?
Or

...perhaps they will look into having it populated with the SMDs, but not the large connectors?

The initial spin for Tom was more or less a copy of the original as provided schematic, just fixing the obvious errors and using SMT. I was not thrilled with the design but agreed to do it as is more or less was (except for the obvious errors). The the three things I didn't like were:
1) * The kludgy use of a SN74HCT245 as a 5V to 3.3V signal converter. This part is NOT specified to work with a 3.3V power supply! It also does NOT have Schmitt-trigger inputs which are a really good idea for this type of circuit. See attached details
2) It made more sense to use DB9 connectors on the PCB, why use a bunch of intermediate connectors and wiring, just extra parts that add cost.
3) I'm not a big fan of through hole components when lower cost SMT components exist, it just adds cost, space and are really old school.

* Note on the TDRO website it states "Note it must be the HCT variant, since it can tolerate 5V inputs while being powered from 3.3V"
This is an incorrect statement, the SN74HCT245 is not specified to operate with a 3.3V supply! So I replaced the SN74HCT245 with a SN74LVC2G14 on Tom's initial board. The SN74LVC2G14 is actually specified to operate with a 3.3V power supply and is designed to accept 5V inputs while being powered from 3.3V. It also has Schmitt-trigger inputs. This is a much better part for this application. The only thing I don't like about it is that this still relies on single ended inputs from the scales and differential inputs are much more immune to noise.


So I built a couple of the -00 boards and tested them, they work, but I just don't particularly like the design.

So I did a spin of the board -01 the way I initially proposed it to Tom, with DB-9's and differential inputs. Using a yet more suitable AM26LV32, this part has differential inputs, 5V tolerant inputs and hysteresis.

I used slightly larger components, so should be easy for anyone with some soldering skill to solder by hand.
For reference:

sn74lvc2g14

https://www.ti.com/lit/ds/symlink/sn74lvc2g14.pdf?HQS=dis-dk-null-digikeymode-dsf-pf-null-wwe&ts=1743267481941&ref_url=https%253A%252F%252Fwww.ti.com%252Fgeneral%252Fdocs%252Fsuppproductinfo.tsp%253FdistId%253D10%2526gotoUrl%253Dhttps%253A%252F%252Fwww.ti.com%252Flit%252Fgpn%252Fsn74lvc2g14

AM26LV32

https://www.ti.com/lit/ds/symlink/am26lv32.pdf?HQS=dis-dk-null-digikeymode-dsf-pf-null-wwe&ts=1743208733333

---------------------------------------------------------------------------------------------------------------------------------------------------------------------

*

 

[mickeyf]

So if I'm reading things right, @djberta did get a couple of boards from Tom, but now wants 2 more. Also, at one point he was going to order some unrelated boards and talked about including these, but that ship seems to have sailed? David got a unit from Paul so he's off the original list. I *might* want as many as 3 - one for Mill, one for Lathe, and one for spare in the event of totally screwing up soldering SMDs (I grew up with point to point 12AX7's then CK722's, and eventually through hole DIPs, but have never done SMD).

Are these 'possibly 5' the extent of the current interest? Anyone else out there?

It sounds like getting just the SM's populated by the board house would likely be prohibitive for just 10 boards?

@slow-poke What size SM is the latest board designed for? Arbutus (post #154, and others elsewhere on internet) suggest that for example, 0805 can be used in a 0603 footprint, and in general one size larger can be done. (?) Of course this does not consider the ESP32 itself.

If I'm reading this right, the E11701 schematic shows a raw ESP32 - no development kit. How is this programmed? I'm not seeing any connections on the board for that? Pre-programmed using a dev kit? Mod the board to bring out the required pins to another connector? Or...?

I don't have ready access to 3D printing; I'd probably want a stencil provided by whichever company makes the boards.
I'm not ready to build a DYI reflow oven. Too many other projects have priority, and none of them are electronics. (I should be out there staking raspberry canes right now, rather than at the keyboard. )
@Arbutus (post #4) says using a toaster oven without a controller is possible. Anyone have any idea what the success/failure rate is liable to be for this approach?

As I mentioned earlier I have no scales yet, so someone else would have to help with basic testing after board #1 was built.

 

[slow-poke]

So if I'm reading things right, @djberta did get a couple of boards from Tom, but now wants 2 more. Also, at one point he was going to order some unrelated boards and talked about including these, but that ship seems to have sailed? David got a unit from Paul so he's off the original list. I *might* want as many as 3 - one for Mill, one for Lathe, and one for spare in the event of totally screwing up soldering SMDs (I grew up with point to point 12AX7's then CK722's, and eventually through hole DIPs, but have never done SMD).

Are these 'possibly 5' the extent of the current interest? Anyone else out there?

It sounds like getting just the SM's populated by the board house would likely be prohibitive for just 10 boards?

@slow-poke What size SM is the latest board designed for? Arbutus (post #154, and others elsewhere on internet) suggest that for example, 0805 can be used in a 0603 footprint, and in general one size larger can be done. (?) Of course this does not consider the ESP32 itself.

If I'm reading this right, the E11701 schematic shows a raw ESP32 - no development kit. How is this programmed? I'm not seeing any connections on the board for that? Pre-programmed using a dev kit? Mod the board to bring out the required pins to another connector? Or...?

I don't have ready access to 3D printing; I'd probably want a stencil provided by whichever company makes the boards.
I'm not ready to build a DYI reflow oven. Too many other projects have priority, and none of them are electronics. (I should be out there staking raspberry canes right now, rather than at the keyboard. )
@Arbutus (post #4) says using a toaster oven without a controller is possible. Anyone have any idea what the success/failure rate is liable to be for this approach?

As I mentioned earlier I have no scales yet, so someone else would have to help with basic testing after board #1 was built.

I sent the manufacturing files for E117-01 to djberta, My understanding is as follows:
- djberta will include the E117-01 board in his next PCB order and then hand populate and test as many as he desires and then possibly distribute the remainder to anyone interested.
- I prefer to not distribute the manufacturing files until the new board is proven and have conveyed that to dj.

Wild guess getting the SMT components populated at CM would probably be in the ball park of $20-30? per board because of the low qty and setup time

There are a total of 6 channels, and you only need to populate the components for the channels you need; 16 total SMT for all 6 channels.
The resistors and capacitors are 0603 size, the 2 large IC's are SOIC16 and the one smaller is SOT-23. The previous board used 6 smaller IC's and Tom struggled with those, I think he was okay with the 0603? Most electronic hobbyists are okay with 0603.

I was tempted to replace the ESP32 development board with a more generic ESP32 module (cheaper/smaller and readily available), but let that desire slip, it would require a few hours of effort. The ESP32 development kit board comes as a 38 pin DIP much like an Arduino board. The one wrinkle with these boards is there are a lot of variations that have subtle differences so you need to make sure you order one with the same pinout/spacing, Tom seems to have a suggested one for cheap from AliExpress.

IIRC: the ESP32 modules come with a factory bootloader, so loading the TDRO provided firmware is fairly straight forward. The module had a micro-USB port, so you just plug it into your PC and then program it. The board can be powered via that USB port. Tom can expand on the programming aspect.

 

[mickeyf]

Ah, yes, looking more carefully at the schematic I see ESP32-DEV down at the bottom of that block. I'll keep an eye on this for if/when djberta has success and extras. Thanks!

 

[Arbutus]

Wild guess getting the SMT components populated at CM would probably be in the ball park of $20-30? per board because of the low qty and setup time

FWIW, a recent quote from a well known Asian PCB fab house was just shy of $500 for 20 boards including a generic ESP32 module ($4.50) The parts count was higher and there were a couple of expensive parts, but that was close to $30/board including testing, delivery and import taxes.

 

[Susquatch]

Just to put one foot on the dance floor, I am still in but ONLY if can get a populated board ready to stick into a box, plug in, and go.

I can hardly solder big stuff today, often failing miserably. I am virtually blind in one eye, handicapped in the other, and shake like a leaf. I have no depth perception left to speak of. So soldering smt stuff is not happening and even connections are hit and miss.

 

[jcdammeyer]

Just to put one foot on the dance floor, I am still in but ONLY if can get a populated board ready to stick into a box, plug in, and go.

I can hardly solder big stuff today, often failing miserably. I am virtually blind in one eye, handicapped in the other, and shake like a leaf. I have no depth perception left to speak of. So soldering smt stuff is not happening and even connections are hit and miss.

I totally get that. I'm finding it harder and harder to solder the small stuff right off. Have to do about 20 or 30 before things settle in.

However I was lucky this time. Notice the small red LED bottom right hand corner. That lights up when there's 12V connected. Or at least it's supposed to. It did on one of the two boards but not the other. A bit of testing with the meter set in diode test mode showed it did light up but it was soldered in backwards. A bit of work with the soldering iron and tweezers and first try rather than 10th it went in and now works. No wonder I was able to buy this one for $10 or so. Maybe they had a whole batch and didn't know how to fix them so just unload on their Aliexpress customers.