botronics

I used a 2N4401 transistor and got the 12v off the Vin on the Arduino Uno, which is powered by an external 12V power supply.

I wanted to avoid drawing more current through the Uno's 5 v regulator. They can get hot easly since I'm using a $3 clone Arduino.

I've had Linksprite Relay R8 board work for about a year. Now the linksprite.io site is not assessable. Can't log in. So now my board can't connect. Is there a recent problem with this site?

It appears the module will work on 5 volts. The board has a 3.3 volt regulator and logic level converts on-board. You can see that on the schematic you posted. Only the IC by itself you want to run on 3.3 volts. So why are you using a CD4050?

It will work with a DTH-11 if you change the #define to DTH11. I found the DTH-11 to be a unreliable sensor and suggest you use a HDC1080. You will need to use the libaray from Closedcube and some of ther example code.

I was able to expand out the code to read other sensors such as light and LM34 temperature sensors. Just add additional fields. I had a problem with character transmission if the value was less than 10. Any additional fields being sent after a low value sensor will not be graphed. It will just make a gap till the value come above 10. This was a problem when I was using a light sensor such as a CDS cell. I found if you not use the dtostrf command and just send the value as a floating variable, it work with numbers approaching zero. I also used a DTH-11 as a sensor and they are unreliable and noisy. Will be using a HDC1080 instead. I also discovered that time scales do not match across data fields. Yet they do when the graphs are zoomed and compared.

By the way, data shows up within seconds at Thingspeak.

How long does it take for data to show up on my account? I built it, loaded the code and have not seen data yet. The ESP8266 give a blue blink (is that a good sign?) so I think its working.

I made it using the module shown and the high power one too. Both from Banggood. Both worked first time. Recommend using the power board too.

Thank you for posting that code. I had the same error. Now it works perfectly.

You can get USB connectors and shells really cheap at banggood.com. No need to chop up other stuff.

I just put one together with the board I purchased at Maker Faire. Works very well. Added relay control and humidity/temperature sensor. For the RTC, I used a logger shield for the Arduino. It has a DS1307 ic and SD card slot. When I get this in a box, I will post photos. Thank you for posting this project.

I wonder if this device is sensitive enough to detect geomagnetic storms during solar flares and CME events. Run a chart and make a corelation with events posted at spaceweather.com to make a confirmion.

One thing I'm finding is once the battery reaches the low voltage point and is discharged, the program does not stop. When the cell voltage recovers, the program will reconnect the load resistor and continue to recycle. If left unattended, it may damage the battery. I would like to see the program disconnect the load and stop.

Answered my own question. Moserial for Ubuntu works very well to log data from Arduino.

Is there a way to save the serial data into a file with Ubuntu?

I'm ready to make one. Will be using a Arduino Uno Relay board I designed. Slight mod to the program will be required. With a relay instead of a mosfet, this completely disconnects the battery after discharge. I can even eliminate A1 adc channel, If I can understand how the program works. This will be a fun project.

I like it. Will probably make it soon. I have some 14500 lithiums to test. Are you working on V 2.0 yet?

This looks like a nice project to test lithium cells. I would like to see it disconnect the battery at a higher voltage such as at 2.7 so as not to damage the cell. Also I would probably change the discharge current to 250 milliamp for testing 14500 cells. Especially when testing low capacity "fake cells".

Can I use any of the analog pins (A0-A5) to connect a servo?

Oops, 14500 cells. My mistake. One thing I wish is that Instrucables would allow the author to make edits on their own posts.

Some people have used a small neo-magnet disc as a spacer to stick to the battery.

The Utiltech flashlight I use an example, will start to dim around 2.7 volts and become obvious charging is needed. I don't think it has any voltage conversion circuity inside. Some flashlights can still be bright at really low voltages that could be a danger to the cell. So a protected cell is a good idea. I just charge my cell every few weeks to keep it up.

Great idea using a 3D printer. I you got one use it.

Did you have to modify the flashlight to fit the 18650?

The lithium cell shown is a common lithium ion 14500 Ultrafire that charges at 4.2 volts. The 18650 you mentioned will not fit the flashlight and can't be used. Only use a 14500 size cell. When in use, the cell voltage will be about 4 volts.

I was able to find Ultrasonic.h at Github. When you compile, the IDE will say it can't find WProgram.h. The only way to fix that error is go into Ultrasonic.h and Ultrasonic.cpp and change WProgram.h to Arduino.h. Make the edit and save. After that it will work.

To make it work, we need the library Ultrasonic.h. Where might I get that?

Can it be made to work on both 800 and 1900 mhz by making one of the dipole pairs larger?

That's correct, Sorry for any confusion.

The protocol is different with iOS. I got s low cost Android tablet to experiment with.