JeVois Tech Zone - Recent questions and answers in Hardware Questions

Answered: How can I determine whether active cooling is necessary for my application?

Mon, 14 Sep 2020 21:49:48 +0000

Yes, the fan is just connected to 5V and always on at full speed. We had some PWM speed modulation hardware logic on a previous version of the board, but that one had other issues, so finally we decided to roll back the design for mass production.

Making a guess based on CPU usage is the best. Anything below 300% should be no problem using a large heatsink like we used in that doc page you mention. We had a deep net running at 375% CPU (i.e., almost loading all 4 cores to the max) and that was stable with the heatsink.

I see DemoArUco around 220% CPU in the screenshots here: http://jevois.org/moddoc/DemoArUco/modinfo.html

So it should be no problem. Make sure you have a good thermal contact with the heatsink. You may want to spread the glue on the chip with a screwdriver or such so that it fully covers the whole chip before applying the heatsink.

camera fails to connect to mac inventor

Sat, 09 May 2020 22:12:43 +0000

I have two new JeVois cameras and I cannot get either one of them to connect to my MacBook Pro workstation with Inventor. I have the latest SD flashed and have the camera connected to separate power with more than enough power. The camera boots up and the indicator light is green and then turns orange. I am using a JeVois Y cable with USB B for the power and micro USB plugged into a micro USB to USB B adapter to connect with the Mac. Inventor is up and running when I plug in the camera to the Mac, waiting for a connection. But the camera never connects. Photobooth and StreamLabs OBS both do not see a second camera other than the laptop built in camera. What other troubleshooting can I do?

Actual FOV of standard lens

Sat, 04 Apr 2020 22:54:42 +0000

I have an A33 Jevois camera with standard lens. I'm trying to use this camera for mapping/SLAM purposes, so I need to get FOV relatively accurately. Checking online, there appears to be conflicting specs on this, where the FOV is stated as either 60^o or 65^o (here http://jevois.org/doc/Lenses.html and here https://www.jevoisinc.com/pages/hardware).

I decided to take the camera to the Vicon motion capture room to see if I could validate either of these figures.

I calculated the FOV by determining the horizontal length a known object was in the camera image, then knowing exactly how far away the camera was from that object, I could calculate the FOV. The figure I kept realising was just shy of 51^o (well short of the 60^o - 65^o).

Have you guys done any testing to determine the effective FOV of this device?

Answered: Saving video directly to a PC

Tue, 11 Feb 2020 21:53:44 +0000

yes, AmCap works, or guvcview on linux can also save video.

Answered: JeVois A33 powers up but LED stays green

Tue, 28 Jan 2020 21:55:22 +0000

You can diagnose boot if you have a USB to serial cable connected to the 4-pin serial port of JeVois. First you edit boot options on the SD card to enable serial console. Then you should see boot messages. See here:

http://jevois.org/doc/Debugging.html

(edit uEnv.txt in the BOOT partition and uncomment the second set of kernel parameters, then launch some terminal program on your host, selecting the port of your USB-to-Serial cable and 115200 bauds).

But usually the problem is either a bad USB cable, weak USB port on the host, or the SD card is not fully inserted into JeVois (try to use a credit card to push it in all the way, just beware that if you slip, it will fly out, so be ready to catch it).

Answered: JeVois Frequently Freezing

Tue, 28 Jan 2020 18:40:33 +0000

Usually, this could be either a problem with the USB cable, or with the connectors. The mini-USB connector on the camera is not designed to handle mechanical stress. If you are moving the camera around to look at various objects, it can sometimes disconnect (even though the connector is still plugged in, the connection gets temporarily broken). Usually when we give demos where the camera moves a lot, we mount it on a tripod and we secure the USB cable to one leg of the tripod so that it will not move at all at the connector when the tripod is moved. Some First Robotics teams have designed mounts with strain relief. Look for 'jevois' at thingiverse.com, for example this one:

https://www.thingiverse.com/thing:2734559

which also has a mount for a ring of LEDs (for night/IR vision).

If the problem occurs when the camera is not moving at all, then the next likely cause is a bad USB cable. We have had a few reports of bad cables. We have changed cable brand since then but maybe try another cable if you have one around.

Answered: Jevois is not detected by Linux (Ubuntu 18.04.3 LTS)

Fri, 10 Jan 2020 18:36:22 +0000

Maybe something happened to your camera or to your USB cable? If you have another USB cable, please try this. Otherwise please email us at jevoisinc@gmail.com and we will help you.

Answered: Interfacing to an ESP32 on RX2/TX2 problems!

Tue, 12 Nov 2019 00:03:18 +0000

just to be sure, those changes should be done to JEVOIS:/config/params.cfg, right? That file his not available in JeVois Inventor so that novices will not modify it. You need to attach the microSD to a computer and then edit it. The entries you need to switch to 9600 baud are already in the file, you can just uncomment them.

This is the only file where serial can be changed, as those changes have to happen first when the camera starts. In initscript.cfg or in the module's params.cfg it is too late to change the serial settings.

Answered: How can i send video frames out the serial port

Thu, 31 Oct 2019 18:37:42 +0000

I think you can do that very easily in python: create a new python module in JeVois Inventor. Then in the process() function get your camera frame as OpenCV BGR numpy array. Then loop over the pixels, convert the BGR values to string representation, and issue a bunch of jevois.sendSerial(string). You should come up with your own strategy to delimit the frames, for example, send the whole frame as one very long string of BGR values converted to hex (2 bytes per B,G,R value), followed by a single \n at the end.

Just beware that the serial port is very slow compared to video frame rates...

Say 320x240 video resolution, times 3 for BGR, times 2 for encoding to ASCII hex = 460k bytes

at 115,200 bauds over the hardware serial port (i.e., about 10 kbytes/s) that will take about 45 seconds for 1 frame.

Powering the camera through the 4-pin connector (according to the arduino tutorial)

Mon, 16 Sep 2019 17:06:08 +0000

Following the pan-tilt tutorial with Arduino the schematic says that the camera should be powered through the red cable of the 4 pin connection using a clean 5V power supply and says nothing about powering the camera with USB.

But the jevois documentations says that powering the camera using a USB connection is always required.

What is correct? This is the jevois tutorial I am referencing: http://jevois.org/tutorials/UserPanTilt.html

Answered: Camera cable extension

Tue, 10 Sep 2019 16:34:34 +0000

You could try something like this:

https://www.aliexpress.com/item/32811483374.html

you want a 24-pin 0.5mm-pitch FFC cable, plus the extension PCB with 2 connectors on it. You connect the sensor to that PCB, and the long cable to JeVois.

Now this may or may not work. We have tried this with a long cable for the AR0135 sensor and it did not get detected. Maybe there is too much loss in the long cable. Since the JeVois PCB is so small (not much bigger than the above adapter PCB with 2 connectors), you may be better off keeping it close to the sensor and looking at using a long USB cable instead, this is verified to work.

Answered: Colors of global shutter sensor seems to be wrong

Wed, 04 Sep 2019 18:00:25 +0000

Yes, this sensor is very "raw" and intended for machine vision tasks, as opposed to our OmniVision sensors which are more intended for consumer products. There is only auto-gain and auto-exposure in the AR0135, no auto white balance, and not even manual white balance. You can ignore the error message, it just means that this sensor does not support a particular control (which may very well be one of the white balance controls). Even though the colors may look different (and maybe not as pleasing), the upside is that they should be more reliable (since the white balance is not continuously adjusted by the sensor).

If you can find the data sheet or developer guide on the web for either AR0135 or AR0134, it will give you some hints (sorry we cannot post it here). For example, looks like these registers are available:

Digital gain:

GreenR: 0x3056
GreenB: 0x305C
Red: 0x305A
Blue: 0x3058

to play with them, do this in the JeVois Inventor console:

setpar camreg 1 # enable access to sensor registers

getcamreg 0x305a # get current value of red gain (should return 20, in hex)

setcamreg 0x305a 0x40 # set new value for red gain (8-bit value)

according to the datasheet: The format for digital gain setting is xxx.yyyyy where 0b00100000 represents a 1x gain setting and 0b00110000 represents a 1.5x gain setting. The step size for yyyyy is 0.03125 while the step size for xxx is 1. Therefore to set a gain of 2.09375 one would set digital gain to 01000011. The maximum digital gain is 7.97x.

Note that setcamreg does not support binary values, only decimal, or hex (with 0x prefix), or octal (with 0 prefix; beware of that one).

You can put those commands into your initscript.cfg if you want them to run each time the camera boots up.

Answered: Does the camera have an external trigger?

Thu, 01 Aug 2019 17:26:58 +0000

We don't have an external trigger but this can be done in principle. You need two things:

1) configure the sensor as "slave" by setting some registers in it

2) Input external VSYNC/HSYNC signals at the connector. With an extension cable and PCB similar to this you should be able to get the job done: https://www.aliexpress.com/item/32811483374.html?spm=a2g0o.productlist.0.0.41bf5dd70r1xDP&algo_pvid=3a9b4b5f-9c6c-443e-91a4-5356cb20c1e0&algo_expid=3a9b4b5f-9c6c-443e-91a4-5356cb20c1e0-2&btsid=ac009a96-79af-4e85-ab65-c35bcc175f44&ws_ab_test=searchweb0_0,searchweb201602_2,searchweb201603_52

but you should design your own PCB that will send the external VSYNC/HSYNC to the appropriate pins on the camera sensor (see below).

Note that we have not tried this, so you would have to experiment. See registers COM5 and COM10 at

http://www.dragonwake.com/download/arm9-download/OV9650.pdf which deal with slave mode.

From what I see in COM10, looks like you would need to provide both external HSYNC (to repurposed RESET pin) and VSYNC (to repurposed PWDN pin).

We provide an interface to set those registers from userland with no need to hack the kernel. First you issue

setpar camreg 1 # allow users to mess with camera registers

getcamreg REG # get current value of a register

# modify the value

setcamreg REG VAL # set the new value

For a software workaround (each camera will still be on its own clock and the frames will not be synchronized), see

http://jevois.org/qa/index.php?qa=440

Answered: it is possible to make tensor flow recognition in hither resolutions ?

Thu, 01 Aug 2019 17:10:17 +0000

I depends on what you are trying to achieve. The TensorFlow models usually are trained for a specific resolution, eg 224x224 or 128x128

In the TensorFlowEasy module http://jevois.org/moddoc/TensorFlowEasy/modinfo.html we first take a central crop of the input video (the grey square shown in the screenshots), then resize this, if needed, to the network's expected input size, then process through the network. The crop size is determined by parameter "foa" with this doc:

Width and height (in pixels) of the fixed, central focus of attention. This is the size of the central image crop that is taken in each frame and fed to the deep neural network. If the foa size does not fit within the camera input frame size, it will be shrunk to fit. To avoid spending CPU resources on rescaling the selected image region, it is best to use here the size that the deep network expects as input.

So if you run at 800x600, you could set foa to 500 500 or whatever else you like. This is best done in params.cfg (see above link).

If you have a trained network that expects 800x600 inputs, then set foa to 800 600 too. The only thing there is that likely your network will run very slowly on JeVois and you might run out of memory depending on how complex your network is.

Answered: Electric noise when using JeVois camera with Arduino

Wed, 31 Jul 2019 19:01:54 +0000

It looks like your power supply to the camera may be too weak. Your connections are fine. Remember that IOREF is an output from the Arduino to JeVois, and it is used to let JeVois know which voltage level the Arduino wants to use on the RX/TX lines (3.3V or 5V). It does not power your Arduino.

I am assuming that you also provide 5V to your Arduino, maybe using a mini+micro USB splitter cable to power both JeVois and the Arduino? Or you provide VCC/GND to your Arduino from some power source? For example see what we do here:

http://jevois.org/tutorials/UserPanTilt.html

note how we have red+black wires to the Arduino VCC/GND in addition to the 4-wire serial connection to JeVois. We connect that red+black pair to a 5V power source.

Or see this: http://jevois.org/doc/UserConnect.html

under section "No host computer but a micro controller"

Answered: Problems with Lenses for ar1035

Tue, 23 Jul 2019 23:12:17 +0000

Sorry for the delay, we finally found time to look into this. You are right for the 170deg lens. It seems that the lens mount used in production is a bit longer than what we had for our prototypes. I will consult with the factory about that. I am also ordering more of the mounts we had used for prototyping. We can ship one to you if you want (please email us at jevoisinc@gmail.com).

I confirm that for the 170deg lens, if you remove the lens mount from the sensor, you need to get very close to the sensor (about 2-3mm from the sensor) to be in focus. The mount is a bit longer than that, so you indeed bottom out with the lens fully screwed in and are still farther than 2-3mm from the sensor. If you need a quick fix, you may want to unscrew the plastic lens mount from the PCB, and then file it down to make it thinner. It looks like it would have to be substantial (take off 4-5mm or so). I would recommend doing that on the rectangular side of the mount (that comes in contact with the PCB) so that you do not compromise the threads on the other side.

We do not see that problem with the 4 other lenses, though, including the 125deg. We can focus all of them no problem as their thread is longer than the thickness of the lens mount (so you can screw them in all the way to touching the sensor).

For close focus, though, you may be better off with a telephoto lens. We have used this one with success (but it is huge, almost as big as the camera, and heavier):

https://www.aliexpress.com/item/32860911092.html

We can get a single keyboard key to occupy the full video frame with this lens.

Answered: Green light remains on

Thu, 18 Jul 2019 18:24:23 +0000

Is the card fully in, as shown in the pictures here:

http://jevois.org/start/assets/images/microsd-card-insertion.jpg

if you have short fingernails, you may want to push it in using a credit card or such, just beware that if you slip, the microSD will fly out, so be ready to catch it.

every unit is tested twice at the factory, so we have not had many defects, but if you believe you may have a bad camera, please email us at jevoisinc@gmail.com with your order number and we will ship you a replacement unit to try out.

Answered: Custom cameras 24pin, 0.5mm pitch, flex, SCCB interface

Thu, 18 Jul 2019 18:20:50 +0000

Both look great!

The ov2715 especially is something we will look into, thanks for your suggestion. The housing is a bit bigger (10x10mm it seems) and will not fit in the case (our default sensor is 8x8mm).

For the ov5640, we do not provide power to pins 23 and 24 which are used by the autofocus. But a version of that sensor with fixed focus should work fine. Those two pins are no connect on our board. So you could also provide the autofocus power externally to these two pins. You will need to get the correct voltage (usually, 1.8V or 2.8V), which you can get from one of the header pin pads on the JeVois PCB.

Answered: Global shutter restock or alternative

Tue, 02 Jul 2019 23:26:12 +0000

Yes, this sensor has been quite popular but getting more is slow as we also have an order for more base cameras currently in production at our factory. Our best estimate now if mid-July. Sorry for the delay.

We don't have an alternative (otherwise we would have used it instead of designing our own PCB). But you can develop your algorithms with the base sensor, the global shutter will work just the same, but with better image quality under strong camera motion.

Answered: I global shutter fan needed

Mon, 17 Jun 2019 18:53:15 +0000

Oh, the label on the stock fan serves as compliance label for the whole device, it was custom made for us. So 5V/0.8A is for the whole camera. The stock fan also consumes about 0.2A.

Mostly, it is about aesthetics, the thicker fan provided with the global shutter kit fits the larger case better. Also, since the stock fan is glued, it may get damaged during the conversion to global shutter, that's why we included a spare one in the kit.

But if your stock fan works fine after removing the stock case, then you can keep it, the air flow for both models is the same.

Answered: Does anyone have a Solidworks or generic 3D model of the JeVois A33?

Thu, 13 Jun 2019 05:35:42 +0000

You can download stl file from this link: http://jevois.org/start/software.html

Answered: Can I take a screenshot and send it when a particular object is detected using aurdino or raspberry Pi

Wed, 29 May 2019 20:48:34 +0000

The easiest is to have your raspberry pi get all detection pictures, and then it will decide which ones to send over email (as opposed to JeVois deciding to only send some pictures to the pi). Then see here:

http://jevois.org/tutorials/UserArduinoBlink.html

http://jevois.org/tutorials/UserArduinoYOLO.html

So you write a python script on your raspberry pi which does this:

- open video capture from JeVois using OpenCV VideoCapture with the correct resolution and frame rate

- loop forever:

    - grab a frame

    - receive serial messages from JeVois

    - if serial message corresponds to desired object, email the frame

Also see this great project by Peter Quinn:

https://hackaday.io/project/163391-front-door-cam

Answered: Suggestion: new B&W fast sensor 360fps

Wed, 29 May 2019 20:22:47 +0000

Yes, very nice, but unfortunately it is only MIPI or LVDS. On JeVois, we use the parallel sensor interface, sometimes called SCCB, or AllWinner calls it CSI. It basically has 8 data bits, VSYNC, HSYNC, a pixel clock, and an I2C port for configuration. If you find other sensors you like with parallel interface, certainly please let us know!

Answered: Is mixing charger and computer safe

Wed, 29 May 2019 20:17:28 +0000

USB ports usually have a power switch IC to protect them, for example http://www.ti.com/lit/ds/symlink/tps2549.pdf

Indeed, without this, one could fry a computer's motherboard just by inserting a bad USB device, shorting the port with a metallic object, etc so it is in the interest of computer manufacturers to always include the protection IC so that they do not have to deal with returned computers with fried ports.

Y cables have been around for a long time because of external hard drives and DVD writers. From the post you suggested, I would say 1) and 2) are taken care of by the protection chip. Indeed there is a risk of 3) in principle which you can resolve by first connecting both grounds together, which usually is what happens first as you insert the USB plugs into the receptacles.

Answered: auto focus set in v4l2-ctl

Mon, 29 Apr 2019 20:09:17 +0000

focus is not supported on JeVois, all our sensors have a fixed-focus lens. The standard lenses have a wide depth of field that is in focus (almost like a pinhole lens), but they still are fixed-focus lenses.

Answered: Arduino Software serial not working when jevois plugged in to USB power only

Mon, 22 Apr 2019 18:55:20 +0000

yes, the JeVois console has no tolerance for typos or syntax errors...

In your first example, your setmapping2 syntax should be:

setmapping2 YUYV 320 240 30.0 JeVois TensorFlowEasy

since with setmapping2, which is for headless mode, you only specify a camera resolution, but there is no USB output resolution, as there is no video sent to USB.

Now when you use setmapping, that should work, you just need to remove the extra space you had before the command. You had " setmapping 35" and should replace by "setmapping 35" (remove the space before "s"). But note that this one will now wait until someone starts grabbing the video over USB before it starts producting outputs (non-headless mode).

Your serial output looks severely garbled. Are you using an arduino running on internal clock (no crystal oscillator)? Maybe software serial is not able to keep up on your arduino, or its clock is not precise enough. You could try to change the baudrate to 9600 and see whether that improves. See

http://jevois.org/doc/UserSerial.html

for how to do this by editing JEVOIS:/config/params.cfg on the microSD card.

Answered: IMU triggered shutter ar0135

Tue, 16 Apr 2019 17:27:35 +0000

Super nice project, thanks for sharing, amazing!

The ICM-20948 natively provides the opposite capability: there is an FSYNC input that you can connect to the VSYNC output of the camera (I am guessing the MPU-9250 has it too?). We are currently exploring this for a future version of the sensor. In principle it should work, but it is very unclear from the docs or the sample code from TDK exactly how (they do not implement anything related to FSYNC it seems). Presumably, the DMP will issue a message or set a flag in the header1 or header2 of existing messages each time an FSYNC pulse is received from the camera.

Would that be usable? We just got the new boards back with that VSYNC-FSYNC connection setup and will be testing it soon and writing a driver for it.

Answered: switching sensor (standard to ov2640 )

Thu, 28 Mar 2019 00:36:17 +0000

Do you have JeVois 1.12.0 on your microSD? The black screen was in previous versions, as the ov2640 driver was not yet complete.

Answered: impossible to detect the micro pro arduino board ( win 7 )

Wed, 06 Mar 2019 00:33:06 +0000

Thanks for your patience, we finally found some time to try this on Win 7.

The latest Arduino states it is for win 8.1 or 10 only, so we downloaded an older version, 1.8.0

We got the full installer as it will also install drivers.

After several times agreeing to install untrusted drivers anyway, the install went well.

Then in the Arduino software, you should select board "Arduino Leonardo" since the Pro Micro is not an official Arduino model. Then plug in your Arduino and select its port.

We did encounter some errors flashing at first. We were connected to a USB3 port on that machine. Looking around on the web, win7 and USB3 have issues with Leonardo. Later we connected to a USB2 port and the code upload worked. I believe it is a known issue with windows 7 and USB-based arduinos that when you reset the Arduino to program it, sometimes win7 will assign a different com port number to it, so the software will not see the Arduino anymore. We were getting that on our USB3 port, but somehow the USB2 port worked ok.

Have a look at this as it might help:

https://forum.arduino.cc/index.php?topic=398898.0

Answered: Wireless serial

Thu, 14 Feb 2019 23:12:23 +0000

and now (continuing from another computer), here is the code we flashed to the bluefruit LE at the time:

// Sample UART relay using AdaFruit Feather 32u4 LE

#include <Arduino.h>
#include <SPI.h>
#if not defined (_VARIANT_ARDUINO_DUE_X_) && not defined (_VARIANT_ARDUINO_ZERO_)
#include <SoftwareSerial.h>
#endif

#include "Adafruit_BLE.h"
#include "Adafruit_BluefruitLE_SPI.h"
#include "Adafruit_BluefruitLE_UART.h"

#define BUFSIZE 128 // Size of the read buffer for incoming data
#define VERBOSE_MODE true // If set to 'true' enables debug output
#define BLUEFRUIT_HWSERIAL_NAME Serial1
#define BLUEFRUIT_UART_MODE_PIN 12 // Set to -1 if unused
#define BLUEFRUIT_SPI_CS 8
#define BLUEFRUIT_SPI_IRQ 7
#define BLUEFRUIT_SPI_RST 4 // Optional but recommended, set to -1 if unused
#define FACTORYRESET_ENABLE 1
#define MINIMUM_FIRMWARE_VERSION "0.6.6"
#define MODE_LED_BEHAVIOUR "MODE"

// Create the bluefruit object
Adafruit_BluefruitLE_SPI ble(BLUEFRUIT_SPI_CS, BLUEFRUIT_SPI_IRQ, BLUEFRUIT_SPI_RST);

// A small helper
void error(const __FlashStringHelper*err) {
//Serial.println(err);
while (1);
}

/**************************************************************************/
void setup(void)
{
//while (!Serial); // required for Flora & Micro
//delay(500);

//Serial.begin(115200);
//Serial.println(F("JeVois Bluetooth Camera Interface"));
//Serial.println(F("------------------------------------------------"));
Serial1.begin(9600);

/* Initialise the module */
//Serial.print(F("Initialising the Bluefruit LE module: "));

if ( !ble.begin(VERBOSE_MODE) )
error(F("Couldn't find Bluefruit, make sure it's in CoMmanD mode & check wiring?"));
//Serial.println( F("OK!") );

if ( FACTORYRESET_ENABLE )
{
/* Perform a factory reset to make sure everything is in a known state */
//Serial.println(F("Performing a factory reset: "));
if ( ! ble.factoryReset() ) error(F("Couldn't factory reset"));
}

/* Disable command echo from Bluefruit */
ble.echo(false);

//Serial.println("Requesting Bluefruit info:");
/* Print Bluefruit information */
//ble.info();

//Serial.println(F("Please use Adafruit Bluefruit LE app to connect in UART mode"));
//Serial.println(F("Then Enter characters to send to the JeVois camera"));
//Serial.println();

ble.verbose(false); // debug info is a little annoying after this point!

/* Wait for connection */
while (! ble.isConnected()) {
delay(500);
}

//Serial.println(F("******************************"));

// LED Activity command is only supported from 0.6.6
if ( ble.isVersionAtLeast(MINIMUM_FIRMWARE_VERSION) )
{
// Change Mode LED Activity
//Serial.println(F("Change LED activity to " MODE_LED_BEHAVIOUR));
ble.sendCommandCheckOK("AT+HWModeLED=" MODE_LED_BEHAVIOUR);
}

// Set module to DATA mode
//Serial.println( F("Switching to DATA mode!") );
ble.setMode(BLUEFRUIT_MODE_DATA);

//Serial.println(F("********** READY *************"));
}

/**************************************************************************/
void loop(void)
{
while (ble.available()) Serial1.write(ble.read());
while (Serial1.available()) ble.write(Serial1.read());
}

Answered: What pitch is serial connector

Wed, 23 Jan 2019 19:26:29 +0000

yes, is made by JST, series SH, pitch 1.0mm, 4-pin

digikey has them, but very tough to crimp, which is why we have stock of pre-made micro-serial cables that are ready to be used.

Answered: JeVois 90 degree FOV IR lense

Fri, 11 Jan 2019 19:15:07 +0000

After looking at the 90deg lenses, I am not sure to tell you the truth. On the 120deg lenses there is a thin film on the back of the lens that looks like it may be the IR filter. But I do not see that on the 90deg lens, so I wonder whether it's just a coating. I will look again under a microscope.

Answered: UART ground connection

Tue, 08 Jan 2019 17:20:05 +0000

There is a single ground in this design, but we did use ferrite beads to absorb any high-frequency noise coming to the connectors. Please see the two relevant sections below. Note that we ended up using transistors with a lower gate threshold for the level shifters, BSS138 instead of 2N7002 in the schematics.

Here is the mini-USB connector. The metal shroud connects to BOX which goes to GND via a ferrite plus a TVS,

and here are the level shifters. Note that BOX connects to two mounting tabs on the sides of the connector which are not pins. The black wire of the micro-serial cable (pin 2) goes to GND via a ferrite.

The CPU is direct connect to GND.

Answered: Updating hardware using Allwinner V5?

Fri, 04 Jan 2019 18:36:41 +0000

Very nice project, thanks for sharing!

That processor is great though I would have preferred more cores and a better GPU.

Lindenis mentions support for tensorflow which is a key element for us, but I could not find any mention that this support is hardware-accelerated using the HAAR accelerator. Can you try to run our tensor flow models (e.g., the quantized mobile nets) on that board and report frame rate? If it is much faster than what we get on our current CPU we will indeed look into that processor in more details.

Answered: Can Jevois be passive cooled?

Fri, 04 Jan 2019 18:29:52 +0000

yes, we have done it, in fact we originally hoped we could get away with a heatsink but it would have to be so big that we finally opted for a fan.

If you are not in a hurry, you can affix a heatsink (we used 30mm x 20mm x 6mm) using heat-conductive epoxy glue.

You will quickly overheat under high load (e.g., tensorflow). But you could reduce the CPU frequency using parameter cpumax documented here: http://jevois.org/doc/UserCli.html

for example,

setpar cpumax 600

will cap you to 600Mhz, You should be able to run heavy loads without overheating at that speed. In fact the RPi slows down to 600MHz when it overheats and has no fan.

Answered: SD card won't stay inserted

Fri, 07 Dec 2018 18:32:33 +0000

Sorry to hear about this. This issue has been rare but a few have reported it. Did you make sure that the card is fully inserted until it bottoms out? Please see pictures at

http://jevois.org/start/start.html

the card should be about 1mm deeper than the edge of the mini-USB connector. If you have short nails you may need too push it with a coin, key, small screwdriver, etc. Just make sure you are ready to catch it, because if you slip with your tool, the card will come flying out.

Answered: Is there a way to connect an external usb camera to the jevois module?

Fri, 30 Nov 2018 00:53:52 +0000

sorry, not at this time. The USB port is hardwired as device, as the Linux kernel support for switching between host and device modes did not work at the time we created the hardware.

Answered: How can i export video frames out the serial link?

Mon, 22 Oct 2018 18:50:16 +0000

Good question, we don't have a facility to support this directly at the moment, but it could be added.

If you are not in a hurry, you can save your image to microSD and then use jevois command fileget from the host to get that file. If you are in a hurry (need low latency), you should transmit the image over the USB video link, which is the default (UVC protocol).

The file transfer stuff is largely undocumented at this stage, though, as it has been reserved for internal use by the JeVois Inventor only.

The basic protocol is as follows:

host sends: fileget /path/to/file

jevois replies: JEVOIS_FILEGET N\n<raw data>

where N is the file size (written out as an ascii string). The raw data sent has exactly that size, then we switch back to command-line interpreter mode.

See here for the jevois side: http://jevois.org/doc/Serial_8C_source.html function fileGet()

and in the inventor we implement the host side: https://github.com/jevois/jevois-inventor/blob/master/Serial.C look for JobFileGet (line 335 and beyond, at the time of this writing).

note that the \n after the size value could be a \r\n depending on user preferences, so the receiver should be able to tolerate that.

Answered: Loose Mini Connector?

Sun, 14 Oct 2018 07:11:43 +0000

Yes, this has happened to us, but usually after things like a pretty rough drone crash, so your case may be milder. Usually we get back on track using needle nose pliers to just squeeze the connector in the camera a tiny bit to make it tighter. We do this in the vertical direction (i.e., squeeze the top metal plate to be be closer to the bottom one). Note that the bottom has a "seam" in the middle, so make sure you squeeze both sides of it upwards as opposed to only the left side or right side.

You can see the "seam" in that upside down view of a similar mini-USB socket (not our exact model but close enough): https://dracity.manufacturer.globalsources.com/si/6008800571690/pdtl/Micro-USB-connector/1010699929/Mini-USB-Socket.htm

We use pliers like this: https://www.homedepot.com/p/Stanley-5-in-Needle-Nose-Pliers-84-096/203901935

Answered: Can i feed an external video stream, instead of using inbuilt cam?

Mon, 01 Oct 2018 21:16:42 +0000

It is possible if you use an x86_64-based PC running Ubuntu 18.04 (or 16.04). You can install the jevois package (deb) files on your PC, or download the JeVois software from github and compile it on your PC. Then you run jevois-daemon on the PC. jevois-daemon is the app that grabs video, processes it, and outputs results.

This is called running JeVois software in "host mode". Have a look at the docs about host mode:

http://jevois.org/doc/Concepts.html

http://jevois.org/doc/JeVoisDaemon.html

From this page: http://jevois.org/tutorials/ProgrammerSetup.html you would just need to install package jevois-host and jevoisbase-host (it will pull opencv and many other dependencies as needed).

You can use any video camera that works with your Ubuntu 18.04 install. Most USB cameras work with no drivers needed.

Answered: Can the camera connector be extended?

Mon, 23 Jul 2018 20:04:12 +0000

The camera sensor uses a 24-pin 0.5mm pitch FFC cable (flat flex cable). We have not found modules with a longer cable, but extensions seem to be available. Look for those specs on google. For example this one:

https://www.aliexpress.com/item/24Pin-to-24Pin-ZIF-0-5mm-Connector-Adapter-with-Extension-FFC-Cable-100-600mm-can-choose/32809530424.html

You would connect the sensor to that little PCB, then the provided longer cable to the PCB too, and the other end of the longer cable goes to the connector on the JeVois PCB.

Answered: Can I save video through a wireless connection?

Sat, 21 Jul 2018 01:19:34 +0000

Maybe the easiest is to use a raspberry pi zero W or regular pi 3, and connect JeVois to the Pi using a short USB cable. Make sure you use a Y cable and also connect JeVois to power as the Pi cannot power JeVois (see http://jevois.org/doc/UserConnect.html ). You capture the video from JeVois on the pi using some custom OpenCV code (search google for "opencv capture video camera") and then stream those frames over wifi. We have not tested it, but maybe mjpg-streamer (described below) or similar exists for the Pi.

You could also try to use an OpenWRT box with the connections shown in the above link (look for the section about OpenWRT). Then run the mjpg-streamer OpenWRT module, see https://wiki.openwrt.org/doc/howto/webcam or the more recent https://openwrt.org/docs/guide-user/hardware/video/webcam

Answered: JeVois went dead no led

Sat, 30 Jun 2018 21:24:44 +0000

Please check this

- usb cable ok? Do you have some other mini-USB cable to try?

- sd card fully inserted? See pictures at http://jevois.org/start/start.html

- usb port ok? Try to plug in some other device like an external hdd, is it working? Try to plug JeVois into a different computer, still no led?

Otherwise, maybe your camera received some physical damage. Please email us at jevoisinc@gmail.com with your order information and we will help you with getting a replacement.

Answered: focusing the lens for close up objects

Fri, 22 Jun 2018 21:21:33 +0000

There is a small dot of glue that was applied to the thread by the factory. This is to avoid having the lens fall off during shipping. You can try to scrape it off with a blade, then you should be able to turn the lens and adjust focus.

We also now have small quantities of sensors with the lens adjusted to 30cm - infinity, and we specifically asked the factory to not glue it, but those also have different lenses: 90 degrees, 120 degrees, or 68 degrees no-IR filter. On those you can adjust focus. Please see:

https://jevoisinc.com for the extra sensors

http://jevois.org/doc/Lenses.html for more info

Answered: Lines on image

Tue, 05 Jun 2018 22:03:46 +0000

Could you email us a screenshot to jevois.org@gmail.com?

If you are operating in low-light and high frames/s, this is normal if the auto gain gets cranked up to the max. You should then reduce framerate to allow for some more exposure time, or use brighter lights in the environment where you use JeVois. See: http://jevois.org/doc/UserLighting.html

But it is also possible that your sensor has gone bad or that the connector for the sensor is loose somehow. In such case, we will ship you a new unit right away once we see the screenshot. We have had a few such cases (but fewer than 1 in 1000).

Answered: Timeout after 5 min on Rasberry pi. Runs for hours with same script on PC. Any ideas?

Fri, 25 May 2018 05:14:26 +0000

yes, most likely a power problem. The RPI is not designed to provide full current on its USB ports, because it is USB powered itself.

the "select timeout" and later "no such device" means the JeVois camera went down, and the PI cannot grab video from it anymore as JeVois was dropped from the USB bus.

Yes, please try with the second end of the Y cable going to a wall adapter, or battery pack, etc and you should be fine. See here for more info:

http://jevois.org/doc/UserConnect.html

Answered: JeVois 1.3MP Sensor with 120deg Fisheye Lens

Wed, 09 May 2018 23:22:42 +0000

Super nice! Thanks for sharing.

There is a GPU shader in jevoisbase that can be used to do correction for barrel distorsion. So far, it has only be used in this module: http://jevois.org/moddoc/DemoGPU/modinfo.html you can set the effect to "Dewarp". But the GPU shading is implemented as a Component that could be re-used in any module you like. See http://jevois.org/basedoc/classFilterGPU.html

As you say, it looks like for ArUco, this may not even be needed, great to know. I wonder whether this is still the case when your ArUco is much farther away, like a few meters away from the camera? I would expect that the distorsion effects should be relatively-speaking smaller over the extent of an ArUco and hence detection should work well too?

Answered: Are there examples to use the camera in arduino applications?

Wed, 11 Apr 2018 04:16:01 +0000

Yes, please start here:

http://jevois.org/doc/ArduinoTutorial.html

then for a specific ArUco following robot see:

http://jevois.org/tutorials/UserRobotCar.html

There is also a pan/tilt head tutorial:

http://jevois.org/tutorials/UserPanTilt.html

Now that we have wider-angle 90 degree lenses available at jevoisinc.com, you might be able to get good tracking without needing a pan/tilt head on your robot, if the ArUco markers you will follow are quite big and/or you run at a higher resolution like 640x480.

Answered: AM Cap software doesn't show split screen

Tue, 03 Apr 2018 18:56:49 +0000

You can also try webcamoid which was recently suggested by a user. We will add some docs about it soon.

https://webcamoid.github.io

With AmCap, maybe your issue is just that you are grabbing in MJPEG, which by default will just show raw video with no processing. Make sure you select YUY2, we have some instructions and screenshots here:

http://jevois.org/doc/UserStartWindows.html

The video modes that involve some processing in the camera use YUY2 or Greyscale outputs to the host computer.

Answered: Fitting M12 Lens to camera

Tue, 20 Mar 2018 18:41:48 +0000

Have you tried a corrective lens placed in front of JeVois? See below for an example with a 15x lens that is coming from a pair of jeweler glasses that has interchangeable lenses. This is a cheap plastic lens with lots of distortion as you can see (and it was not very well aligned), but we can focus well on the tiny text on that 2.5" hard drive at a very short distance from JeVois. For 4-6 inches, maybe about 5x lens would do the trick.