How to add camera to Thingy91, HELP!!!

[Parishad]

I am doing a project for smart fruit fly trap/ detection with Thingy91 and the camera to take a picture periodically. There are no nrf9160 I/Os left on the Thingy 91 board. Could you please explain me how to add one or is it not possible to do it?

[Achim Kraus]

Do you know nRF9160 Feather ?

The Thingy:91 is great to be used "out of the box", but as you wrote, no direct I/O are available. You may try to connect something at the nRF52840 (USB+BLE Mikro-Controller on the Thingy:91), and forward the data to the nRF9160. Or you switch to the nRF9160 Feather (or one of the variants of it.).

[helsing]

Hi Parishad,

It is possible to use Thingy:91 for prototyping. However, for general and convenient development we recommend the nRF9160 DK. As Achim points out, there are also other options for compact prototyping. I have not yet tested the nRF9160 Feather myself although it is likely also a good option.

Anyhow, if you prefer to proceed with Thingy:91 the schematic for Thingy:91 is available here. Make sure to download the correct files for your HW version, for example for HW v1.6.0 . Schematic for older versions are available here.

• Some pins are reachable on Thingy:91 through test points. Here is a list of test points on the Thingy:91.
• The SPI interface for nRF9160 can be found on TP34, TP35 and TP36.
  

• I2C can be found on TP9 and TP10:
  
  The I2C lines are shared between nRF52840, nRF9160 and a couple of sensor devices as well as the PMIC. To avoid any potential conflicts with the PMIC I would recommend to try to set up an additional I2C interface with some other pins before testing TP9 and TP10.
• There is also the possibility to solder wires onto components like the button SW3(to get access to P0.26 on nRF9160). Here is the list of pin maps on Thingy:91.
• In addition, two of the N-MOS gates are connected to a test points TP32 and TP33, since the drain & source are only connected to connectors, you can use these GPIO however you want to. You will get a bit more capacitance due to the transistors then.
• P0.10 on TP7 is also not in use (unless you close the solder bridges in order to connect it to INT2 of ADXL362 or ADXL372)
• The nRF52840 SoC has 6 spare GPIOs available on P6. You could set up this SoC as a connectivity bridge.

Please see the following discussions regarding how to get access to various pins of Thingy:91.

 https://devzone.nordicsemi.com/f/nordic-q-a/68213/thingy91-uart-external-communication

 https://devzone.nordicsemi.com/f/nordic-q-a/74083/thingy-91---i2c-pins-voltage-level

 https://devzone.nordicsemi.com/f/nordic-q-a/64459/can-the-spi-pins-be-used-as-gpio-on-thingy-91

[helsing]

By the way, here is a nRF Connect SDK sample demonstrating the Arducam Mega camera sensor. The Arducam Mega module is unfortunately not yet released. However, some concepts might be relevant for your project. 

[Achim Kraus]

If you want to keep using the Thingy:91, you must also take care of the IO voltage level. The Thingy:91 may supply 1.8V and 3.3V, but the IOs are 1.8V. 

AFAIK, the camera runs on 3.3V (or 5v), you may connect the camera to the 3.3V supply, but you need to check, if it works with the 1.8V I2C, or if you need a level shifter (e.g.  Adafruit 757, Bidirektionaler Logikpegelkonverter BSS138).

The nRF9160-DK can be switch to 3.3V IO level, and the feather nRF9160 v5 uses already the 3.3 V for IO.

[helsing]

Thank you, Achim, for highlighting this very important detail. Yes, as mentioned in one of the links provided, the IOs voltage for nRF9160 on Thingy:91 is fixed at 1.8V, so a level shifter will be required.

Parishad, which specific camera module are you looking at using? I would recommend checking with the module manufacturer regarding IO voltage. They might have some tip or trick or another module available compatible with IO voltages down to 1.8V.

(By the way, I noticed that the Arducam Mega module might already be available now, as a free sample to students. This module, however, also requires 3.3V IOs)