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Messages - Tim

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Support / Re: Simblee assembly and pick'n place machines
« on: May 14, 2017, 01:49:45 PM »
Thanks Tom.

Another change in our process is to attach the programming header to the board before applying power to the USB shield. I understand damage can occur if I/O pins are connected before power is applied. The theory is beyond me, but I've learned this from a trusted source.


Support / Re: Simblee assembly and pick'n place machines
« on: May 14, 2017, 08:54:20 AM »
Some additional ideas in attempt to improve our hand assembly yield.

1) Change I/O pin assignment to reduce number of adjacent pins in use.

2) Remove from PCB any pads for Simblee pins not in use.


Also, we've cleaned up our handling procedures to eliminate ESD events that could damage chips.



Support / Re: bad Simblee batch?
« on: April 24, 2017, 02:21:25 PM »
We'll be receiving more Simblees from DigiKey tomorrow and will be assembling. Results will be revealing. I also noticed different colour, but that could be because of rework. These are chips that were removed from boards after failure.

We recently ordered from Mouser because they were $3 cheaper. It could be coincidental that we started having assembly issues with this batch. Will post more here as we learn.


Support / bad Simblee batch?
« on: April 23, 2017, 01:14:33 PM »
Hi ..

Trying to explain why we're getting a high failure rate on assembling our boards. We recently ordered from Mouser and received 30 Simblees packaged as in photo, which means someone handled them to take from factory packaging and place on foam. Also found a label on the anti-static bag containing the Mouser order that have never seen before (see attached photo). Wondering about possible ESD events during handling and shipping that damaged chips. Previously all Simblees came from DigiKey and in original factory packaging and we had a much higher success rate. Wondering if anyone has had issues with Simblees arriving defected from different suppliers.

Appreciate any thoughts, experience.


Support / Re: Simblee assembly and pick'n place machines
« on: April 02, 2017, 04:26:57 PM »
Thanks Tolson. I'm hopeful that smearing flux on Simblee pads before overlaying stencil and applying solder paste will do the trick. Will post here again once we have a sense for helpfulness.


Simblee Libraries / Re: Simblee library 1.1.1
« on: April 02, 2017, 04:24:33 PM »
Thanks Tolson. Has 1.1.1 proven to be a stable release for iOS platform?

Simblee Libraries / Simblee library 1.1.1
« on: April 02, 2017, 08:28:19 AM »
Hi ...

I see that Simblee library 1.1.1 is available, but don't see any announcements about it. Anyone aware of details of the update? Release notes?



Support / Re: Simblee assembly and pick'n place machines
« on: April 01, 2017, 08:51:09 AM »
A couple new ideas that might be helpful?

First, would applying extra flux to the Simblee pads on the PCB before applying solder paste with stencil be helpful?

Second, after applying solder paste to board (with stencil) and before placing Simblee, how about melting the solder paste over the Simblee pads with a soldering iron to get the solder attached to the tiny pads. At that point could make sure there are no solder bridges. Then position the Simblee over the pads and reflow.

Thoughts? Thanks,


Simblee Libraries / Re: SimbleeBLE affects TIMER1/2 accuracy
« on: March 30, 2017, 08:08:12 PM »
Thanks for posting RF Digital response. Good news indeed. Glad the post has been helpful. It's been fun learning.



Support / Re: Simblee assembly and pick'n place machines
« on: March 30, 2017, 08:05:35 PM »
Thanks for your thoughts. We might sell 500 in a year and hand assembly is fine given that quantity. Would like to discover a method that yields zero defects. For environmental reasons, would rather not use lead solder. Using a 3D printer sounds interesting. Would have to invest in one and then do a lot of learning, experimenting, but might be worth considering, so thanks for the idea.

Are you using lead solder? Any particular reflow oven?

Many thanks.


Support / Simblee assembly and pick'n place machines
« on: March 28, 2017, 11:59:21 AM »
Hi all ..

Currently we're hand assembling our boards. Our PCBs are manufactured by OSH Park. We use stainless steel stencils by OSH Stencil. We use lead-free solder paste by MG Chemicals. We use the Whizoo reflow oven. We're not yet at a quantity that makes automated assembly practical.

The problem is that for about one in 15 boards we hand assemble, the Simblee has an alignment issue or an invisible solder bridge and does not work. It's time consuming to fix.

We are considering desktop pick and place machines both to eliminate this issue and speed up assembly. Does anyone have experience with any of these:

Any others? Thanks for any thoughts, advice.


Simblee Libraries / Re: SimbleeBLE affects TIMER1/2 accuracy
« on: March 19, 2017, 08:38:05 PM »
Hi Jeff,

Yes, micros() is inaccurate when BLE is on due to priority of the BLE stack. That's what led me to use PPI, GPIOTE and TIMERs because they are not subject to CPU or BLE. Not sure about delayMicroseconds(), but I presume same issue. micros() is just reading the value of RTC1, so if you could use PPI and GPIOTE to start and stop RTC1 and read it's value in an interrupt routine, that might do the trick. I don't have much experience with encoders, so I might be way off here.

I'm very interested to hear RFDigital's response. If you're using PPI, GPIOTE and TIMERs to "handle encoder interrupts," my understanding is it should work.

Thanks for adding to the conversation.


Simblee Libraries / Re: SimbleeBLE affects TIMER1/2 accuracy
« on: March 17, 2017, 09:58:08 PM »
Hi Jeff,

With this line:

attachPinInterrupt(EXTERNAL_ENCODER, encoderPulseCount, HIGH);

I presume you want encoderPulseCount to be called when pin EXTERNAL_ENCODER goes HIGH, correct? I don't know why it's causing SFM to break.

You could try using GPIOTE to fire the GPIOTE_IRQn interrupt routine for both throttlePin going high to low and EXTERNAL_ENCODER going low to high. You would add this code:

Code: [Select]
              | (GPIOTE_CONFIG_MODE_Event << GPIOTE_CONFIG_MODE_Pos);

Then instead of having two interrupt routines (reportTime and encoderPulseCount), you would have a single interrupt routine that would test which interrupt has fired and then call either reportTime or encoderPulseCount.

Code: [Select]
if (NRF_GPIOTE->EVENTS_IN[1] == 1) {
} else if (NRF_GPIOTE->EVENTS_IN[2] == 1) {

With my limited experience, this is what I would try.

Maybe others will have suggestions.


Simblee Libraries / Re: SimbleeBLE affects TIMER1/2 accuracy
« on: March 12, 2017, 02:45:38 PM »
Hi Jeff,

It would be helpful to see some code, even if just the standalone code. I'm not experienced with PWM but I've learnt the whole PPI mechanism of Simblee/RFduino and happy to assist if that's where your issues lie.


Support / Re: Simblee - OTA programming?
« on: January 30, 2017, 05:53:22 PM »
Hi ...

A bit of info to share that might be helpful.

We hand assemble our boards too using the following providers:

- PCBs manufactured by OSH Park (
- stainless steel stencils by OSH Stencils (
- reflow oven by Whizoo (

Our board provides access to UART pins (see image1). We use a 5-pin header to hold onto to PCB while programming occurs. Wires from this header are connected to 7-pin header which connects to the USB shield. We connect everything, hold the 5-pin header inserted into the UART access point on the board, then initiate programming from the Arduino IDE (see image2).

I agree, it would be convenient if Simblee shipped with the OTA bootloader onboard so initial programming could occur OTA.

Your sketch does not need to call ota_bootloader_start() when using the Nordic iOSDFULibrary. All that's necessary is that your sketch include ota_bootloader.h. OTA can be initiated by the iOS app connected to the Simblee via BLE.

Hope helpful ...


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