new teensy owner with questions...

[garyd9]

Good morning, I recently purchased a teensy 3.6 for use in a project of mine. I'm not sure the 3.6 is the best board for my project, but I needed a tiny, fast board and teensy seems to be regarded very highly. (I also wasn't sure which teensy to get, but the shipping cutoff time only gave me a few minutes to decide, so I figured I'd be better with too much power than not enough.)

I won't actually have the teensy in hand until this weekend, so some of my questions might be kind of abstract.

My intention is to use the teensy to communicate certain status information with a PC via the USB port. The teensy would actually be inside the PC case and powered directly from the PC's ATX power supply (5v line) with the VUSB trace on the teensy cut (so if the 5v line turns off, the teensy also turns off even if the USB line is still powered.)

(BTW, please pardon me while I specifically thank PJRC for the extremely simple way to cut the USB->Vin trace. On a arduino pro micro, it's not possible. On a Due, I had to attempt to desolder a mosfet the size of a grain of sand. (which I failed at, but I did manage to saw it off with an exacto knife.))

As mentioned, the USB will used for communication (message passing), and I've seen suggestions that I can actually use raw HID to communicate with the PC instead of a serial emulator. (Thank you!) Are there any examples floating around of using raw HID on the teensy 3.6 talking to Windows? I'm fairly fluent with Windoze programming, but never attempted raw USB HID before...

With the above, there might come a time when I want to reprogram the teensy (without physical access) through the same USB connection I'd normally use for passing messages. I assume that my program will need some way to kick the teensy back into a bootloader to get into whatever mode the teensy uses for loading programs. I found code for teensy 2.x modules to jump directly into the bootloader (https://www.pjrc.com/teensy/jump_to_bootloader.html), but I can't seem to find anything similar for teensy 3.6. Is it possible for the teensy 3.6? If so, where is the bootloader address I'd jump to? Is there a better way to handle this situation (of wanting to reprogram the teensy?)

Would it be safe to encase the teensy in hot glue (after making all my needed connections, of course) while leaving the reset button, SD slot opening, and USB connector exposed? My hope is that I can drop the board into a small metal box after encasing it in a hot glue insulator. If there are any parts on the teensy that might require a cooling, what are they and can I just use thermal tape to attach a heatsink to them before encasing in glue? (The hot glue would serve an additional purpose of securing solder points - my soldering skills suck.)

Thanks in advance (and thank you for the new toy.. er.. platform..)
Gary

 

[KurtE]

As for Raw Hid: you might take a look at the page: https://www.pjrc.com/teensy/rawhid.html

Yes you can typically reprogram the Teensy through USB without having access to it. (After it has been programmed before). As a fail safe you could also add remote button, to go into program mode.

As for hot glue?

Hopefully others can give you more complete answers

 

[markonian]

I found code for teensy 2.x modules to jump directly into the bootloader (https://www.pjrc.com/teensy/jump_to_bootloader.html), but I can't seem to find anything similar for teensy 3.6. Is it possible for the teensy 3.6? If so, where is the bootloader address I'd jump to? Is there a better way to handle this situation (of wanting to reprogram the teensy?)

Beware, that page is old and does not apply to the ARM based Teensies (3.x, LC).

However, be aware that Teensyduino provides the

_reboot_Teensyduino_()

function. Calling it makes the Teensy behave as if the user had manually pressed the program button on the Teensy. _reboot_Teensyduino_() is available for both Teensy 2 and Teensy 3 series.

You'll still want to have access to a real program button though for the case where, say, you've programmed the Teensy with a program that crashes and the Teensy can't call _reboot_Teensyduino_().

 

[garyd9]

As for Raw Hid: you might take a look at the page: https://www.pjrc.com/teensy/rawhid.html

Does that sample teensy code apply for teensy 3.6? It includes: "WARNING: obsolete, use Teensyduino for new projects."

Beware, that page is old and does not apply to the ARM based Teensies (3.x, LC).

I'm noticing a lot of that with the "how to" tips section of that webpage. Thankfully, teensy is well supported with forums.

However, be aware that Teensyduino provides the _reboot_Teensyduino_() function.

That looks PERFECT. So I can better help myself in the future, is there some reference material where could I have found information about "_reboot_Teensyduino_()"?

However, be aware that Teensyduino provides the

You'll still want to have access to a real program button though for the case where, say, you've programmed the Teensy with a program that crashes and the Teensy can't call _reboot_Teensyduino_().[/QUOTE]
I'll still have access, though it'll require opening the computer case, pulling out the box I keep the teensy in, opening that, etc.  (It'd be annoying, but not impossible.)

 

[KurtE]

Does that sample teensy code apply for teensy 3.6? It includes: "WARNING: obsolete, use Teensyduino for new projects."

There is probably two parts to this.

Example code to run on the Teensy... You should look at the Teensyduino install. If you have not already done so, you should install the latest Arduino and the latest version of Teensyduino.

Then choose a teensy (probably 3.6 as that is what your ordered) as current board.

Then go to File menu -> Examples -> Teensy -> USB_Rawhid -> Basic

And it will load up an example program for the Teesy. To compile you will need to set the USB type in the tools menu to one that includes raw hid. Probably not many choices here (raw hid, and maybe all of the above).

You can then maybe try the example windows raw hid program for windows from that forum page. Also the source file you can download contains the source for the example windows program as well as linux, ...

 

[garyd9]

...and the latest version of Teensyduino.

Then choose a teensy (probably 3.6 as that is what your ordered) as current board.

Then go to File menu -> Examples -> Teensy -> USB_Rawhid -> Basic

Ah! that's the part I was missing. I wasn't aware that rawhid was one of the examples provided in arduino with teensyduino. I haven't loaded up teensyduino yet. I will tonight, though, so I can "look around" while waiting for the teensy's (teensies?) to show up. (I ordered a second 3.6 w/ pins so I can play around on a breadboard before whipping out the soldering iron.)

Thank you
Gary

 

[Wayne]

Some time back I used a Arduino UNO (did not know about Teensy then) and CanBus board and a PC running ThinBasic.
The Thinbasic was used to read the CanBus code from the serial of the USB and display a action if the function was activated.
The UNO read the CanBus code and output it as a serial communication which the thinbasic was monitoring on that serial port.

I was able to create a graphic screen (buttons, Joystick, pressure switches) with all the functions of the device I was testing including analog reports.
You push a button, the screen location of the button lit, you move a joystick, the screen lit at the button and display the value of the analog signal.
Still in use today for testing a Medical devices called TSO's. I think Table Side Operator or something like that, been sometime since I made it.
Was one of my 1st time using Andruino IDE.

 

[aFewBits]

Hot glue? One, it's not going to improve a bad solder connection. Two, it will guarantee you'll never be able to repair a bad solder connection.

IMO, hot glue has some good uses in electronics but potting a Teensy and it's connections in the stuff is absolutely not one of them.

 

[garyd9]

Some time back I used a Arduino UNO ...

While I sincerely appreciate feedback to my questions, I'm having a hard time connecting your experience with what I'm asking (or anything I'm doing.) I'm sure there's some connection, but I'm just missing it. Can you please point it out to me?

Hot glue? One, it's not going to improve a bad solder connection. Two, it will guarantee you'll never be able to repair a bad solder connection.

IMO, hot glue has some good uses in electronics but potting a Teensy and it's connections in the stuff is absolutely not one of them.

I agree that it won't improve a bad solder connection, but if the joint isn't as mechanically sound as is ideal (even if it's electrically sound), a dry layer of hot glue can help it withstand mechanical stresses. (It's also a great insulator if using a metal project box.)

So, despite it being a Bad Idea for some (or even many) reasons, would it be unsafe or cause any problems that wouldn't have otherwise existed?

I realize it won't make me a soldering wizard and I know it makes the board unserviceable. Those are acceptable to me considering the fact it makes a great insulator and barrier... but if there are parts of the teensy 3.6 that should NOT be insulated or smothered in hot glue to avoid risk of creating new problems (such as a component overheating, or something that might react badly to the glue), I'd like to know so I can avoid putting glue on those parts (or, in the case of heat, I can attach a heatsink to the part.)

Think of the hot glue as a perfectly form-fitting 3D printed plastic case that just happens to get permanently sealed when closed.

 

[aFewBits]

Unsafe? I don't think so. Cause any problems? Probably, likely, maybe, it depends.

The problem with consumer hot glues is that you have no idea of what's in the stuff. Most of it is EVA with tons of other material mixed in, paraffin and other cheap crap left over from various polymerization processes. Overall, you have no idea what the insulation/dielectric properties are.

The stuff will eventually creep under the BGA processor and it does oxidize, everything does. Given the spacings, I would expect problems, certainly long term concerns there. IMO, putting a big blob of unknown material across 100-200+ MHz signal lines on tightly spaced pins is a sure fire recipe for strange, unpredictable behavior.

if you were buying industrial hot glues with a MSDS, you might have a chance of predicting the result. A bag of clear sticks that fits your gun that were on sale for $0.99, well, you get what you pay for.

 

[garyd9]

Unsafe? I don't think so. Cause any problems? Probably, likely, maybe, it depends....

Okay, that's fair. As an alternative, what if I only actually put the hot glue on the bottom of the teensy board to "glue" it into the metal box? (And then coated the rest of the inside metal box with the glue just to act as an insulator - but contact with the top of the teensy would be incidental and only with glue that's already dried.) There are still plenty of exposed traces/pads on the bottom of the teensy, but at least no BGA components.

I suppose I might be able to use liquid electrical tape to "coat" the box instead, but that stuff usually isn't as resistant to puncturing as hot melt adhesives, and I'd be concerned about shorting. Perhaps a combination might work? Coat the bottom of the teensy with liquid electrical tape, and then set that into the hot melt adhesive?

Using the metal box is really a PITA...

The alternative to this would be having to figure out the process of designing a custom 3D printer layout for a teensy case and getting someone to print it. Being that I don't know the second thing about 3D printing, that would be a time consuming (and possibly expensive) process.

(I wonder if I can use this as an excuse to get a 3d printer... hmm...)

 

[aFewBits]

A 3D printer certainly has merit but IMO, the simple solutions are usually the best place to start, perhaps something like this:

https://www.tindie.com/products/loglow/teensy-3536-breakout-revision-a-standard/

I have no connection to the Tindie vendor, just presenting one of many possible solutions for mounting in a metal box.

PS: My last comment on hot glue. The stuff never "dries". In general terms, it is a polymer, it only changes state when heated and cooled. It never cures in the sense of normal glues/epoxies and the more you persist in attempting to reinforce your beliefs that hot glue is an acceptable material around HF electronics, the more you exclude proper solutions. See http://xyproblem.info/

 

[KurtE]

I have not used that one by Tall Dog, I used a couple of his DIP ones https://www.tindie.com/products/loglow/teensy-3536-breakout-revision-a-dip-64/
Which worked nicely for prototyping... But does not have the mounting holes...

When I built the 2nd one, I modified it slightly to use Tall pins to connect the Teensy to it, but that was for different purposes. Allowed it to plug into breadboard, with only 1 pin on each side of breadboard free. Tall pins then made it easy to hook up logic analyzer or the like... But again different purpose.

As for 3d printer. I have one which I use from time to time, and I am also waiting for Kickstarter $99 3d printer which hopefully will ship in October. So you can always try them out for not too much investment. As for prototyping building one, I have done a few simple adapter boards, that would convert from one of my boards with Teensy installed to match up with other boards or the like. These type of 3d designs are usually pretty simple to do.

But I think a lot of this may also depend on is this a product, where you expect to make several of them or simply a one off type design for your own usage? Mine are for my own playig around, so the fact that it may take 30 minutes to print is not a problem... But if you are making lots of them, then would look into having one of the 3D printing company make them for you... You also have the possibility of having someone local to where you are print it for you. There is (or at least was) a website where you could choose someone near you and simply send your design to them and they would print it on one of their own printers...

 

[garyd9]

PS: My last comment on hot glue. The stuff never "dries". In general terms, it is a polymer, it only changes state when heated and cooled. It never cures in the sense of normal glues/epoxies and the more you persist in attempting to reinforce your beliefs that hot glue is an acceptable material around HF electronics, the more you exclude proper solutions. See http://xyproblem.info/

I think perhaps I was a bit passive in my conversation which led to the wrong idea. Thank you for the "xy" link to remind me that I wasn't asking for anyone's permission to use hot glue and that I'm not asking anyone to "solve a problem" for me in this regard. I know that it's safe securing PCB's with hot glue. I've done it for years with simple boards and never had problems. Not only for reinforcing the mechanical aspect of solder joints, but also for simple mounting and holding things in place on PCB's. The cost of the teensy board is low enough that I'm willing to continue taking any possible risk with it for my current project.

My concerns and questions are limited to if there are any issues, specifically, with the teensy board and it's components that might manifest if something is covered with the glue or insulated when it shouldn't be. A perfect example is the possible issues of it seeping under the BPA processor.