rgordon
Hi All,
I have been away from this site for far too long. I am currently catching up on all the great looking projects going on! Sadly, I have not had much of any time to work on robots....but, I do still want to be involved with EZ-Robot in some form even though this is not a robot project. So if any of you are interested in helping out, I would be very grateful.
I work at a power plant in South Boston, Virginia. We have truck tippers that actually tilt the tractor trailers up at a 60 angle so that the wood chips dump out the back. (No, the truck driver doesn't stay in the truck 
).
I have been tasked with building a custom display to indicate the current wind speed on a two digit seven segment display. The catch? The display needs to be (2) feet tall so that the bulldozer operators can read the wind speed from up to 300 feet away in broad daylight! They do not want the truck tippers to be used if the wind speed is greater than 32 MPH. I will custom build the displays using L.E.D. strip from superbrightleds.com
I'm using this LED strip because of its intense brightness.
What I would like to do is utilize an EZ-B v4/2 Wi-Fi Robot Controller to measure the analog voltage from a Anemometer that I purchased from
The output from the anemometer is 0.4V (0 m/s wind) up to 2.0V (for 32.4m/s wind speed). I will need to convert this to MPH and display it on the two digit seven segment display. I will need the EZ-B outputs to turn on transistors that will drive each segment of each display so that they will form the correct digits to indicate wind speed.
So...what do you think? Can we do this? Anyone like to brainstorm on this? 
Rex
Hi Rex,
Definitely doable. I like the idea of using an LED Strip to display the numbers. You could even use frosted acrylic to diffuse the light and make it look like a very large 7-seg LED. Kinda like this. A Black background would likely work well. I wonder what LED color would look the best in broad daylight? Maybe Blue, Green, or Red.
MOSFETs would likely be the best way to drive the LED strips as they can handle a lot of current and don't heat up as much as Transistors under load. Please note though that you would need a type that can be driven by 3.3V Logic (LVTTL compatible).
As for the Anemometer you could hook it up to VIN on the EZ-B and power the EZ-B from a 7.5V or 9V power supply. Then run the blue cable to one of the Analog pins.
Doing some quick calculations: The Anemometer output starts at 0.4V and maxs out at 2V so that's a 1.6V range. 1.6V divided by 32m/s is 0.05V per 1m/s. Just do your mph calculation and you then have your speed!
Do you have access to AC voltage near the display installation?
Hi Jeremie! Good to hear from you.
Yes I will have access to 120V AC in the truck tipper control panel. Yes I have seen the display from Evil Mad Scientist Laboratories. Just not quite big enough
. I'm going to 3D print the segments and arrange them into a seven segment display and have a frosted lens on each segment to diffuse the light. Each digit will have to be about 2 feet tall to be seen from 300 feet away. I think Green with black background would be best but I could be wrong.
So the EZ-B outputs are only 3.3V? Not a problem. I can use a level shifter like this if need be.
The big question is.... "Will the EZ-B be able to keep up with the changing wind speed? Because to make digits this big, they have to be very bright so, I have to use this kind of LED strip to light the individual segments of the display. Therefore, to display a wind speed of say, 20 MPH, the EZ-B would have to turn on segments a, b, g, e, d for the "2" on segment "A" and a, b, c, d, e, f for the "0" on segment "B" like in this picture:
Unless you know of a better way to do this. I was just concerned if the EZ-B could keep up with the ever changing wind speed; having to turn on and off that many segments so fast.
This should be a fun build. Always wanted to build a giant seven segment display!
Tell DJ that I hope to find more industrial applications for the EZ-B!
Rex
Rex, seems like at great idea! I like it. Green on black looks good.
Don't worry about the speed, the EZ-Bv4 can definitely handle 14 I/O pins switching the segments faster than the Anemometer can be read (which is very fast).
You can always use the EZ-B benchmarking control to see how many analog reads and digital writes you can do per second.
Actually I would recommend slowing it down as you probably don't want the segments switching rapidly, smoother is better.
Hi @rgordon, It is fun to see an EZB in a different type of application. It will be an interesting project to follow. Thanks for sharing.
welcome back rex! Missed you. Great post!
Hi Andy and Dave! Good to see that you guys are still here. Got a lot of catching up to do on what everyone is up to....
Don't know if you are really set on using a seven segment display BUT did you think about just using two regular traffic lights one on top of the other? You can pick them up on surplus sites. I say one on top of the other, would give you six lights, each one represents five miles and hour in wind ( you could even color code them from green, yellow and red ). It can be seen from that far away I believe. Anyways just a thought ... throwing out other ideas.
Good luck in what ever you come up with.
There’s a project in the examples folder for using a 7 segment lcd display. Although, this could be done with Blockly but that example is ezscript. Either way, ARC can do it