How to communicate wirelessly 20+ sites to remote Laptop

Hi All

I am VERY new to electronics (finance background … so all foreign to me), but have a problem I need help with.

I need 20 different items that need to be measured and data sent wirelessly to remote laptop.

One company I spoke to offered me a $3500 “sensor” per unit to do the job, so the conversation ended very quickly.

I bought (w/end just past) an arduino board, an ultrasonic sensor and breadboard and now (for <$40) have it measuring onto my laptop.

Next issue is to get 20 of them (as proto-type) to locate in field and communicate wirelessly to laptop. If successful, the qty will go to 1000 immediatley. I would like to avoid a sim card in each.

can someone please assist me to take step #2
(appologies for length of above … my first ever “blog”)

D :o

How far apart are these sensors? Since you mention SIM cards, I assume it's a substantial distance?

Hi wb

the distance varies ... they can be as close as 2m or upto 200m. The land is undulating and trees / motor vehicles / properties can block line of sight

In my naivety, I won't my Ardunio to run the sensor tests, the light tests, then once a day transmit the data (assuming that is the cheapest way to communicate the data - as opposed to live feed).

It will also need (via CRM) 2 way communication so if an issue is flagged, you can "refresh" and check it wasn't a false read. This is a nice to have option (if not too pricey)


It sounds like a job for radios - 200m would be a bit much for the cheap 434MHz examples and you might struggle to manage 1000 of them all trying to send at the same time. An XBee mesh network would do it, though they're not inexpensive. Compared to $3500 apiece though, they're a phenomenal bargain.

The below might be of interest.

I'd suggest the hope RF packet radios such as the RFM69HW one from Anarduino

There is a very good Arduino library that supports these little packet radios called RadioHead

I believe these little modules also can form a mesh network. Following the link you can see that they are very inexpensive at slightly more than $4. If you are looking for an inexpensive but powerful Arduino compatible board I'd further suggest a Teensy LC for $12.

However, given that you are so new to electronics I am wondering if the scope and advanced technical nature of your project are a little too much too early. Give yourself some time!

thanks WB / ZKat & Hroom for your time and comments

I will read a bit about your suggestions and then take a punt and see how I go

Are you allowed to ask in these forums about any consultants in the Melbourne Australia region that could assist or is that taboo

I find if i take a prototype into someone (other project working on) people are happier to "improve" and "pick it apart" rather than going in with an idea and asking for input (a lot of blank faces and "can't be done" attitude)

thanks again D

Melbourne is a pretty large city and I am sure they have a decent maker space. I'd try to find a place where you can connect with like-minded people that can help you without them doing it for you.

A "professional" consultant is likely far out of your price range!

Here is a link to a post on the Teensy forum that describes a solution using a Teensy 3 and a Hope RF69HW. The Teensy LC was designed to be mostly pin compatible with the Teensy 3.x so the adapter described in the post should work, but even if it is not it should be very easy to change it to a slightly differnt pin-out.

The real work will be in the software, as you'll be able to gather for the thread. Something else you should keep in mind when designing your system is power consumption. What you describe sounds like a battery operated device that will be deployed outside for long periods of time. wiFi for example is relatively power hungry.

Another topic to consider is that these small radios send in a license free frequency range, which is not the case with very low cost WiFi modules. For a setup with 20 devices that may not be a problem, but for a setup with 1000 that may be a differnt story.

hi Headroom

I am trying to keep up with you .. are you saying that small radios will not be reliable enough on 1000+ units and best I focus on XBee?

Or are you saying low cost WiFi won't be able to handle 1000+ units and for me to concentrate on small radios?

I was hoping to use a 9v battery hooked up to a tiny solar panel (to tackle charge) to use as power supply (assuming that is sufficient). I was hoping to do "sketches" and "send data" once a day to reduce power consumption (but again ... am now only 9 days old in the electronics world

thanks (I'll read a bit more about Teensy link) Derek