9 replies to this topic

[Stu R]

Hi everybody! Firstly, let me confess that I am completely new to Netduino, and embedded development in general. I do have some reasonably solid experience with C# though, and it is this that atteacts me to Netduino over Arduino. I was hoping some of you guys might be able to give me some feedback on the following project idea.... I have an 8 year old son, who unfortunately is severely autistic. Normally, we keep a very close eye on him and our house is very secure as a result. However, a few days ago, he managed to give us the slip and ran away from home (first time ever). Somehow, he managed to evade our frantic attempts to find him until the Police found him nearly a mile away (he is a very fast runner) apparently making his way to school (it was a saturday!) Whats the point of all this, I hear you ask. Well, I was wondering if there might be any milage in using Netduino or a similar device to prototype some kind of tracking system that would SECURELY and SAFELY show his rough position on Google Maps or similar, so that we could track him down using our phones if this ever happened again. Preferably not in such a way that he would always be visible, but only when we requested. I realise the board would be too large, fragile and expensive to be sewn directly into clothing or anything like that, but this is only a prototype right now, so bag/pocket would be fine. I havent thought too much about the exact implementation yet - apart from whatever I do must put his safety and security first - but I would love to hear from you guys and your thoughts. Oh yes, and Im very much looking forward to getting into Netduino, Im afraid I might have some very 'newbie' questions until I get some experience!! Thanks, Stu

[CharlesTucker]

Hi Stu, your message caught my eye for several reasons. Your message is about positioning, which always has my interest, I am also very new to the Netduino and choose it over the Arduino because of C#, and have a daughter with an autistic disorder (fortunately not severe, Asperger, which is a rather mild form, often (also in her case) combined with a rather high intelligence and I don't need to worry about her running away).

Anyway, about your project, as I am a beginner myself, I probably can not help you much. But often just discussing the topic already helps. You would somehow need to combine a GPS receiver with a way of communication, using the Netduino as the "glue" between those. The GPS receiver is not that difficult, on this forum there are several posts about people connecting a GPS receiver to the Netduino.

As far as communication, I think, but let others correct me, there are two options, both require mobile phone technology. One is using short messages (SMS), you send a message to your son's device, and it responds with a message containing its location. The other option would be using GPRS to communicate with your son's device, either from a computer or from a smartphone with internet access. On your end you could probably use a smartphone with a (homemade) app that either plots your son's location on a map, or points in the right direction or so. For inspiration, you might want to look at http://www.gpsdrive.de, which is an open source project aimed at creating a navigation solution for Linux, Max and Unix. It also includes a "Friends server", which might help you, think of your son as your friend in this case.

Also, for sure such devices must be available for sale (although creating your own is much more fun and rewarding). GPS Magazine regularly compares such commercially available devices, you might want to have a look at GPS Magazine, either to select something suitable for you and your son, or for inspiration.

With best regards, Peter

[Chris Seto]

This would not be a difficult project at all, and if we were talking about a toddler that could not go THAT far, you could even use a high powered RF module. The only issue there would be the antenna. Otherwise, you could get off with a custom PCB containing a GPRS module, Netduino chip, USB port and a GPS-on-a-chip such as the SkyTraq Venus. Power could be supplied by a single cell lipo and could be recharged through the programming USB port on the device by a chip such as the TI part BQ24010.

[JonnyBoats]

First off, let me say how glad we all are that your son is safely home again. Also welcome to the Netduino community.

Before proceeding it is extremely important to remember the difference between a hobby project and a safety critical device involving life or death. The "gold standard" for being found in an emergency is a EPIRB (and it's little brother, the Personal EPIRB, or PLB that fits in your pocket). These are extremely rugged, waterproof, tested to the highest standards and have long life batteries. Unfortunately one needs to press a button to activate them, so this is probably a "show stopper" for your application.

Another common device with a built in GPS and communication capability is a cellphone or smart phone. In an emergency authorities can easily locate a cellphone provided it is turned on and within range of a tower. It is highly unlikely that you can engineer a solution with similar capabilities at a lower cost than a used cellphone.

As far as a hobby project is concerned, you might want to consider fox hunting, where you simply attach a small transmitter to your son that sends a radio tone for a couple of seconds every minute or two. To locate the transmitter one only needs a simple receiver and a directional antenna. This is how biologists track animals in the wild. See http://www.predatorc...diotracking.htm for details. Newer versions often include a GPS as well. Here is a link where someone did it on the cheap http://www.thefintels.com/aer/frs.htm to find model rockets.

Finally there are commercially available pet tracking devices such as the Garmin Astro.

[Nevyn]

Another common device with a built in GPS and communication capability is a cellphone or smart phone. In an emergency authorities can easily locate a cellphone provided it is turned on and within range of a tower. It is highly unlikely that you can engineer a solution with similar capabilities at a lower cost than a used cellphone.

If you are looking at smartphones then what about the iPhone "Find my iPhone" feature. Working on the assumption that if you can work out how to stop a kid from losing a home brew piece of kit you should be able to do the same with an iPhone.

Regards,
Mark

[Fred]

I tend to agree with some of the comments above. Whilst the Netduino is a capable platform and would be ideal for a "fun" project this sounds like a more physically robust and smaller solution would be better. The first thing that springs to mind for me is something like an Android phone with built-in GPS that you can write a custom application for. (As far as I know you can't intercept or interact with calls or SMS messages on an iPhone.) You can get a low-end Android phone cheaply and would just need a bit of Java coding. A while ago I wrote a Windows Mobile application for when my wife called as I was motorcycling to/from work. The application would respond to a missed call or SMS from specified numbers and would send a reply telling her when I left work, how far away I was and a calculation of when I'd be home. It sounds like something similar might suit you. You could have the GPS off to save battery. On receipt of a SMS you could turn it on, grab a position and send it back. Your son wouldn't need to do anything. There would be plenty of options from this point - Google Maps integration, regular position updates incase he's got no GPS fix when you need it, auto answering your call and enabling speakerphone, etc. I'd offer to help, but since Sunday I've been very busy with a son of my own.

[Chris J]

Hi,

I know this is an old thread but for what its worth I'll throw my bit in.

At the moment I work as a program/developer for a tracking company and your very issue of tracking children comes up from time to time. The solution could be found using a Netduino. I would think that your parts list would go something like this

• Netduino
• Telit GE864-GPS
• A GSM Evaluation Board - Basic 50-Pin

Or

• Netduino
• GSM-GPRS-GPS-Shield

The Telit GE864-GPS is a good pick as it offers some solutions to other issues that you will face. It will allow you to use a single com port to access both the GPRS and GPS at the same time. It also has every thing needed to maintain a battery as well (charging and low level alerts) This means that you could run the full project of a Netduino mini.

But this leaves the bigger things to deal with such and power (how many hours between charging ?, GPS lock and drift and of course data and live time tracking.


Given this you might find that a pre-built unit might do you better. I have seen many different ones over time but at the moment I think the pick of them is the Handheld GPS/GSM Tracker GH3000 .

• Alarm button - Think panic button
• Voice calls - has some preset numbers it can dial
• Loudspeaker - You can call it direct as a auto answer hands free
• Polygonal Geofence zones - if it gets to far from your house/school it starts to send SMS's
• Silent call - Send it a SMS and it will call you back, with no lights or sounds made.
• Remote control by SMS - You can SMS it to change operational modes.

A few other gems it has is that in standby it will get you a day or so. It also sends SMS's to a iPhone that provide a click through to Google Maps.

[SirPoonga]

I also have been interested in GPS tracking. I want to put a tracker on my new motorcycle. One, for security if someone takes it. But I doubt that will happen. Two, when I go on a trip it is logged and if I need something people will know where to find me. The most popular commercial products out there use GSM which probably the easiest and most effective way for a commercial product. However, being I am working on a DIY solution I am going to look at APRS. APRS is a data transfer system built on top of ham radio. That does mean I have to get a ham radio license. Check out aprs.fi to see if there is anyone using it near you.

[bobk]

I also have been interested in GPS tracking. I want to put a tracker on my new motorcycle. One, for security if someone takes it. But I doubt that will happen. Two, when I go on a trip it is logged and if I need something people will know where to find me.
.
The most popular commercial products out there use GSM which probably the easiest and most effective way for a commercial product. However, being I am working on a DIY solution I am going to look at APRS. APRS is a data transfer system built on top of ham radio. That does mean I have to get a ham radio license. Check out aprs.fi to see if there is anyone using it near you.

Another option that I was thing about would be to use GPS and tie it into the ham radio APRS system using netduino. You would need a radio, but with many solutions out there already, it might not be feasable, but fun to do.

[Paul Newton]

In an emergency authorities can easily locate a cellphone provided it is turned on and within range of a tower. It is highly unlikely that you can engineer a solution with similar capabilities at a lower cost than a used cellphone.

If you are looking at smartphones then what about the iPhone "Find my iPhone" feature. Working on the assumption that if you can work out how to stop a kid from losing a home brew piece of kit you should be able to do the same with an iPhone.

I understand that it is a requirement in the US and EU that phones can be located by the emergency operator.
Lots of private companies are providing services based on this capability, and it does not have to be a smart phone:

The first one I found using a Google search Mobile Locate is aimed at business owners who want to track their staff - its pricey with a monthly subscription and is aimed at multiple phones.

However there are also companies that offer a service aimed at home users FollowUs - this company has a pay-as-you-go service that works out at 50p a go.

Since these services are available now and don't need any home brew development, I would make them my first option.

Paul