Electron Project Discussion [Hardware]

I think the data consumpyion wouldn’t be so bad. Are you talking abouy overall data usage, or just the Electron not supporting sending that muvh data at once?

The OV-7670 I think has something like a 640×480 resolution, so with 1 or 2 images per day the data usage should be tolerable. Especially if an image could even be resized a bit or something to be made smaller? I don’t know what the Electron would be capable of dping in respect tp this

Yes with the right SIM plan sending the pictures would not be a big deal.

@Dave did get a Photon to send high-resolution images from a camera to a local server so it can be done but the image data needs to be small as possible for cellular ideally.

The Electron can send the data, so that’s not the issue.

I just so far have not seen anybody figure this out with the Electron yet, maybe somebody has I just haven’t seen it yet on this forum at least.

Maybe Dave has an idea about how to do this.

hello Vitesze, i do not know if this is a consideration for you , i remember reading a few other threads before when imaging was discussed and the point was made that the images, pictures and/or video clips, are generally large files that use quite a bit of the overall data limits, which translates to costly. so you probably will want to also look at if any ways are available to reduce the size of the image files prior to transferring.

There are cameras that compress the image to Jpg compressed format and save it to a SD card.

I think the real question is can we upload a jpg file from an SD card attached to an Electron to a server online.

Thanks for your reply. I think the file size isn’t much to worry about; Particle alreafy has a good plan for only an extra $1/MB, and if anything I can decrease the frequency of picture-taking (e.g. none on the weekends or during nights when generally very little waste is disposed anyway). Doing this could reduce it to maybe only 20-40 images per month, which at the OV-7670s low resolution shouldnt translate to a very high volume of data

I’m more worried about how to get a picture from the Electron to a web server; it’s different from the traditional data publishing after all

Also, really appreciating everyone’s replies so far, it’s helping a lot!

I was reading a post by Rick who said FTP uploads on the Electron took almost three times the data file due to the overhead of the FTP transmission standard.

Check out this thread.

Thanks, I’ll look into it some more tomorrow.

For now the picture-taking is not a main worry for me; the initial device will not have it yet and I want to ensure it works first, before adding a camera to it. Good to know in advance though what the struggles here will be for it. I should do some calculations and see how much data usage I’d be looking at, and see if its worth it still

It’s possible to send pictures but getting to happen consistently and reliabiliy seems to be the issue with the current feedback from people who have gotten uploads from an Electron working.

So what are the 10 units you already have deployed doing? What types of sensors are they using? What size can’s are they attached to?

ADXL-362 and VL53L0X sensors right now, to monitor pickups and fill ratios (latter one seems somewhat reliable, but the larger the can the bigger the inaccuracy gets). They’re attached to anything from 2 yard to 8 yard containers, and tote cans (similar to the one most people would have at home).

Right now I can’t think of any other sensors being yoo usefup yet besides a camera.

It seems multiple VL53LOX sensors would be better for gauging overall fullness vs just one sensor.

Are you just pointing the sensor down into the can and have it positioned in the center?

I would think a single VL53LoX sensor would do good for the Tote cans.

This is school project / test?

Multiple sensors was also my idea - it’s just that there’s always the possibility of a large object blocking the sensor completely and causing false readings until it is (re)moved. Then again this risk would also be present with a camera, ultrasonic or other sensors.

The sensor right now is placed on the side at an angle, so that it looks slightly beyond the center point of the container.

This is an internship project organized through an university, yes. The investments aren’t too high but the possible benefit of this kind of sensor is interesting. I think I got the bulk of it down now, I’m just waiting to see if the LiSOCl2 batteries work well, and also waiting on some acrylic glass that needs to protect the VL53L0X sensors as I find over time moisture starts to affect them a lot (after a week and a half, 5/10 sensors no longer could take accurate measurements). Also going to test some other antennas as the Particle Taoglas antenna doesn’t nicely fit in my enclosure.

I was thinking that 3 sensors pointing down along the back of the container would work best to one area from blocking a single sense. The downside is the enclosure would need to be bigger/longer to accomplish that.

The VL53L0X sensor for sure needs a protective covering over it to prevent dust, dirt, liquids from getting on or in it. I would think the Ultrasonic sensors would really suffer from this over time since they can’t be covered up all the way.

What does the Datasheet for the VL53L0x say about the right type of material that should be used to go in front of the sensor for best results? I’m sure not just anything would be best.

I have a laser cutter and some .23 inch thick clear acrylic but never tried to put it in front of the sensor to see how it affects performance.

Here is a new longer-range LIDAR sensor @peekay123 pointed out to me the other day which may be ideal for the bigger containers. Although I think multiple VL53L0x sensors pointing down would do the job better than a signle sense.

Yes, ideally you’d have several sensors on different parts of the bin to almost get you that 3D-view; but both financially, operationally and logistically I think that will be quite troublesome.

For ultrasonic sensors, the JSN-SR04T should be waterproof, but I don’t know how it holds up against grime over time (they also don’t seem to absorb water well at all). I had a good look at the datasheet of the VL53L0X beforehand, and it made recommendations on the recommended thickness and the transmittence for wavelengths (thickness should be 1mm or less and transmittence minimum 90% around 940nm if I recall correctly). So I followed these criteria in selecting the appropriate protective layer (coated acrylic glass should be perfect for this). .23 Acrylic I imagine would be way way too thick, so I had mine industrially-produced.

I too think more than 1 sensor is better here. With the VL53L0X I’m able to get measurements up to about 230cm, which is more than enough for virtually all containers as even the larger ones usually don’t extend beyond about 180cm. So as far as conventional distance sensors are concerned, I think the VL53L0X really is the best pick for this application, taking into account the costs and current draw

Can you link to the acrylic type you picked out? I would like to try it also with the VL53L0x sensors I have here to see how it affects performance.

So were you able to fix the sensors that stopped working by letting them dry out or are they just dead? The holes in them are tiny so it wouldn't take much to block their ports.

Are your 10 sensors being used by the trash company now or are you just seeing how they work for sending the data for now?

I got those made here: http://astraproducts.com/ asking for hardcoated (scratch-prevention) filters with a 0.5mm thickness and minimum 90% transmittance between 930 to 950nm. They haven’t actually arrived yet so I will let you know if it actually works. But going by the datasheet of the VL53L0X, it should meet the standards. Also, I have seen another project where people also used acrylic glass for the VL53L0X, so it definitely should be possible.

The sensors still work fine. After I took them off and inspected them, they had tiny water droplets (or just moisture) on them, blocking the signal. One wipe was enough to make it work again. I imagine though that once you pour enough water on it, they should eventually stop working, so I want to be careful with them now. Also, as winter is approaching I imagine the freezing and thawing of water would have a destructive effect on them too.

The 10 sensors are used by the trash company yes, but more as in a pilot study. The accelerometer looks very good, and when the lasers work they do give fairly accurate data too. Once I can implement some improvements on them we will probably get more and use them for real.

The JSN-SR04T I haven’t actually used yet in the field, as the measurement angle is so ridiculously large (something around 50-55 degrees when I self-measured it) I favoured the VL53L0X.

On another noter; what are you thoughts on detecting whether an Electron woke up from Deep Sleep due to RTC timeout or WKP High signal?

I found there’s two ways people recommend to do this; either by fetching the current day/time, or by directly measuring the WKP pin right after waking up. However, I’ve now read that with retaining variables over long periods of time (for me this will be up to 24h) they may not always be stored properly, and for the WKP pin signal I have trouble detecting it. Is there anything specific you would recommend? It’s not a huge issue for me if I can’t do this, it’s just that it will save me an extra couple % on the battery lifespan.

There are a few different ways I have seen other people deal with it but you can use the Retained Variables function to store data that will save through a power reset.

I don’t think there is a way to detect if the device woke from RTC timeout or WKP pin when using deep sleep. I’m not really sure though since I have never attempted to do this before.

@RWB, @Vitesze, there is a PR coming to a release soon I hope:

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Question though is, is this only going to work for Stop sleep mode, or also Deep sleep?

@Vitesze, I’ve posed that question to @avtolstoy on the github PR.

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