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Dongle w/ Reset Switch

Today I prepared a tailor-made system consists of five MewPros and one Dongle for a patron of our shop.

The regular customer saw our latest blog post and liked to update their system to fulfil those “Tips” or conditions written there as soon as possible. 🙂

The following is the image of the unit:

There is a hazard switch (as usually seen in a car), which is the reset. The button is known to be useful in the following cases:

  1. After assembling MewPros, GoPros, Dual Hero, and Dongle(s), some cameras are power on and some off. This is a normal situation but a bit unstable. Then please try pushing the reset button for getting the same effect as detaching/attaching all MewPros and Dongle.
  2. After powering on the master camera, sometimes we see an alert message “3D SYNC LOST”. In this case please wait until power goes off automatically. Then please push the reset button before the master camera’s power button. It will solve the problem.

Remark: If you are one of other MewPro 2 customers and also like to update ATtiny1634’s fuse (B.O.D.) or firmware please contact us. Generally, we will give firmware updates free of charge.

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MewPro 2 in Germany

Last week I went to Germany and saw a 3D rig made by a customer.

The system consists of a lot of GoPro Hero 3+ Black’s and MewPro 2’s.

Tips To Make MewPro + Dongle System

I realized the following six points/hints while I was there in Germany:

1. Random Power-On Bug

Here in Japan I’ve never known such a bug existed, but in Germany I also experienced that some GoPros do power-on randomly even after they received the power-off, “PW0” command. The bug is fixed now at GitHub (cf. dcc9a4f783ba381f5caa646a835adb78884ea01d)

2. Better Connect RESET

For small sized genlocking system I thought it was overkill to connect all RESET pins of MewPro’s and dongles each other; because if something wrong happens then simply detaching/attaching the MewPro or dongle will solve the problem. However, if it is a large system involving a lot of GoPro’s and MewPro’s then connecting RESET and pushing reset button on Arduino Pro Mini of the dongle much helps to solve the unstable situations.

3. Daughter Board As Hub

Genlock Dongle is shipped with a complementary daughter board (photo: below).
As you can see, the board has the identical design in soldering area of Genlock Dongle: There are aligned/connected pins for HSYNC, TRIG, VSYNC, GND, RESET, and TXD. Using the board as a “hub” to MewPros, after finished soldering to the hub you could use six (or five if you don’t connect RESET) wires connecting each group of pins on the board to the corresponding pin on the dongle. Soldering like this way is much easier than soldering all the wires directly upon the dongle.

4. Keep Soldering Joint Shortest

I realized the following pitfalls in soldering wires:
Wires and solder joints should not touch the camera body (photo: above) as they pry up the herobus connector and cause insufficient contacts.

Wires and solder joints should not touch Arduino Pro Mini board of Genlock Dongle (photo: above) as they cause short circuit.

5. Temperature Controlled Soldering Iron Recommended

Don’t use old soldering irons before the sensitive electric era. Newer Atmel microcontroller forgets firmware or bootloader or everything, or dies if it is too hot.

6. B.O.D. Enabled

Distributed power system with a lot of batteries and wall chargers like GoPros + MewPros + Dongles + Dual Hero should have B.O.D. (Brown Out Detection) enabled whenever possible. Otherwise while connecting elements followed by an element a small amount of power might be unintentionally supplied to it through signal lines, even if the power lines disconnected or off, and its microcontroller will be likely to runaway because of insufficient voltage. According to this observation from now on our MewPro 2 will be shipped with bootloader in setting B.O.D. 1.7V.


It is our pleasure to know/see how MewPro products are actually used. So please don’t hesitate to invite us! Our staff will go to your place immediately. 🙂

And please pronounce MewPro as /mjuːproʊ/ in English or cat meows/miaows + Pro(fessional). The author was very surprised in Germany that they say it differently.