As a reaction to my previous stories on the caravan/mobile-home leveler I received mail from a few readers that wanted to know if they could test the caravan/mobile-home leveler on a PC.
The previous stories on this project showed how to install the software on your mobile phone. Installing it on your PC for testing at home is actually easy to do.
The MicroPython program for the ESP8266
First thing to do is to adapt the program for the ESP8266. In the project the program creates an access point. For using it at home you need to start the program as a wifi device.
To adapt the program, connect the ESP8266 to your computer with an USB cable and start Thonny to Edit the program.
MAKE SURE TO REMOVE THE BATTERIES BEFORE CONNECTING THE ESP8266 TO YOUR COMPUTER. NEVER USE BATTERIES AND THE USB CONNECTION AT THE SAME TIME AS THAT MIGHT DAMAGE YOUR ESP8266 OR EVEN WORSE: DAMAGE YOUR COMPUTER BEYOND REPAIR.
I will give here the part of the original program we need to change. It looks like this
'''Caravan and Mobile Home leveling aidhttp://lucstechblog.blogspot.com/Version with http serverThe x and y values are roundedESP is configured as Access Point'''frommachineimportPin,I2Cimportutimeimportmathfromlucsmpulibimportinit_mpu,get_dataimportsocketimportnetworkssid='Caravan-Leveler'password='123456789'ap=network.WLAN(network.AP_IF)ap.active(True)ap.config(essid=ssid,password=password)whileap.active()==False:passprint('Connection successful')print(ap.ifconfig())i2c=I2C(scl=Pin(5),sda=Pin(4),freq=400000)# esp8266init_mpu(i2c)
This is the part where the libraries are imported and the Accesspoint is activated. Replace this part with the following code:
'''Version with http serverversion where the x and y values are roundedESP is station'''frommachineimportPin,I2Cimportutimeimportmathfromlucsmpulibimportinit_mpu,get_dataimportsocketimportnetworkssid="YOUR-ROUTERS-NAME"pw="PASSWORD"print("Connecting to wifi...")# wifi connectionwifi=network.WLAN(network.STA_IF)wifi.active(True)wifi.connect(ssid,pw)print('Waiting for connection.',end="")whilewifi.isconnected()==False:utime.sleep(1)print('',end='.')print("")ip=wifi.ifconfig()[0]print("Connected with IP adress : "+ip)i2c=I2C(scl=Pin(5),sda=Pin(4),freq=400000)# esp8266init_mpu6050(i2c)
And this is what you should replace it with. The program now acts as a standard wifi device (station), makes contact with your browser, and gets an IP address. The reswt of the program stays the same.
Make sure that you replace YOUR-ROUTERS-NAME and PASSWORD with your routers credentials.
You need to run the adapted program with a USB connection to your computer as we need to get the IP address the ESP8266 has gotten from your router. Your's will of course be different.
And now we have the IP address.
The Javascript program.
The Javascript program is more than 300 lines long. Use a text editor like notepad to load the program. An HTML file is just a plain ASCII text. Use the search function in the editor to find this line:
Then save the file with exact the same name in a directory on your PC. Open that directory and click on the HTML file.
And here is the caravan/mobile-home leveler running in my browsers screen on my PC.
Clicking anywhere in the screen with your mouse will open the program full-screen. Clicking the red exit button in the top-right corner makes the screen smaller again. You can resize it to any size you like and the program will adjust automatically.
Several parts of the program were taken from my book on Javascript: Javascript tips. This book does not teach how to program in Javascript but gives more than 500 tips that can make programming in Javascript a lot easier.
This is the third part of my project on building a caravan/mobile-home leveling aid.
The video shows how this device works. You put the box on the table or floor of your caravan/mobile-home and outside you can level the caravan by looking at the screen of your phone/tablet. The devices are connected by Wifi. No need to walk back and forth to see if your camper is level.
This story tells how to build the program for your mobile phone.
The structure of the (Javascript) program
The program is written as a web page with Javascript. This makes it very small (about 7k) and portable. It will work on a computers screen, a tablet and on your phone.
There are some tricks in the program.
- It will automatically adjust to the width and height of your screen. - If you resize your screen (on a notebook) it will adjust automatically - There is a text that is made visible on the screen and then disappear - Clicking the window/screen resizes it to full screen - Received data from the ESP8266 is text the program converts it into a floating point number - The floating point number is converted to an integer value - The horizontal and vertical lines are made with CSS - The centre circle and the bubble are created in CSS
The program itself is fairly complicated and more than 300 lines of code. And to tell the thruth: I was fairly proud of myself when I got it all working.
- It starts with CSS code to draw the lines, the centre circle and the red bubble. - Every second it fetches the x and y values from the ESP8266 - These values are put at the bottom of the screen - It tests if the values are positive or negative so it knows where to position the bubble - The x value is then converted to the position on the half of the screen height. - The width of the bubble is halved and with the converted x value determines the place of the bubble on the length axis. - The y value is converted to the position on the half of the screen width. - The height of the bubble is halved and together with the converted y value determines the location of the bubble on the width axis
As stated the program is an HTML file. So it is a website with Javascript that fetches the data from your ESP8266 and displays that graphically. This means that there is no quit button. To stop the program you will have to close your browser.
The code uses some neat tricks that come from my book Javascript tips. That book is not a tutorial about programming in Javascript but just a book chock-full of tips and tricks that show how to get things done in Javascript.
The program.
Like said above the program consists of more than 300 lines of CSS, HTML and Javascript code. So it is far to large to discuss here in detail. I also do not want to publish it here as that would make this page too bulky. Therefore I herebye give you two options to download the code.
Point your QR-code reader program here and you will get a link to the download location.
This is the download link. Click this link and you will be directed to the download location. You can also copy this link and then open it in your browser to visit the download location.
Click the light-blue part where it says caravan-level-html
At the bottom of your screen a message will appear and click on the Download button.
After a very short time a new message will appear telling that the file has been downloaded and that you can open it. Don't do that at.
With your file manager on your phone open the downloads folder. And there is the file caravan-level.html Click that file.
The file has (of course) the name caravan-level.html
The file is now permanent on your phone/tablet. So when on the camping site just go to the phones settings. Select the wifi settings and connect to the caravan-leveler accesspoint.
The previous story in this series showed how you can connect to the hardware device with an Android phone. The procedure for a tablet is of course likewise. On a notebook you will need to find the Caravan-Leveler accesspoint and then connect to it's IP address with your browser. I presume the procedure for an Apple notebook/Ipad or Iphone is likewise but unfortunately I do not own these devises so I can not test that. Please read that story so you know how the procedure works. You can find it here: http://lucstechblog.blogspot.com/2024/05/caravanmotor-home-leveler-part-2.html
Then open the file manager, go to the downloads folder and click the caravan-level.html file.
And there it is. And the caravan is on a steep slope in this picture !!!
All files for this project (until now)
https://app.mediafire.com/jpswchudmlwu5
This link is useful on your PC as it directs you to the folder on Mediafire where you can download all files for this project: the hardware schematic, the STL files for the case, the MicroPython file for the ESP8266 and the HTML file.
That is all.
Well just one more thing. On this weblog I discussed a nice web-service that allows you to turn a web-page into an app. Just search this weblog and you will find it.
This is the second story about building a caravan/motorhome leveling aid. This story focusses on the software for the ESP8266.
Short intro: I am going to show how to build an electronic device that you can put on your motorhome/caravan's table. And then that device sends it data to an app on your phone. So you can go outside and look at your phone's screen while leveling your caravan/motorhome !!
The above video demonstrates how the device works. It is not connected to an USB powersupply as it is powered by batteries. And the hardware communicates wiressly with the phone.
Programming the ESP8266 is done with Thonny as the program is written in MicroPython.
If you want to know more about Thonny and programming in MicroPython please consider buying one of my books listed at the bottom of this page. These books focus on the Raspberry Pi Pico and Pico W (the wifi version) but most of the programs and details also work on the ESP8266 and ESP32 after altering the pin numbers.
Considerations.
In a previous story on this weblog I demonstrated how to get human readable data: plain angles in degrees from an MPU6050. That program is usefull for starting several projects. But that framework displays it's data in Thonny's shell. You can find that story here: http://lucstechblog.blogspot.com/2024/04/mpu6050-data-in-degrees-instead-of.html
That is of no use for this project. We want to see the angles in a simple manner on our Phone's screen. So the program needs to send it's data over wifi. The caravan/mobilehome leveling aid is build for campers that are installing their caravan/mobile home on a camping site or in the free nature. The problem that occurs in such situations is that is most of the time no wifi is available. So the software needs to start as a Access Point (AP) so your phone can contact it.
The other thing to consider is that the information that the ESP8266 is going to send over Wifi must be accessible on your phone. So it must be send in a form that we can pick up by a program for Android.
Both issues are taken care off in the next program.
The MPU6050 Library
Using the MPU6050 in a MicroPython program requires a library. A MicroPython library is actually just a MicroPython program that simplifies a certain problem. In this case the problem is the communication with the MPU6050.
For your convenience I hereby give the library as discussed before:
'''Luc Volders library for MPU6050'''frommachineimportPin,I2Cimporttimedefinit_mpu(i2c,address=0x68):i2c.writeto_mem(address,0x6B,b'\x00')time.sleep_ms(100)i2c.writeto_mem(address,0x19,b'\x07')i2c.writeto_mem(address,0x1B,b'\x00')i2c.writeto_mem(address,0x1B,b'\x00')i2c.writeto_mem(address,0x1C,b'\x00')defread_data(i2c,addr,address=0x68):high=i2c.readfrom_mem(address,addr,1)[0]low=i2c.readfrom_mem(address,addr+1,1)[0]value=high<<8|lowifvalue>32768:value=value-65536returnvaluedefget_data(i2c):readx=read_data(i2c,0x3B)/16384.0ready=read_data(i2c,0x3B+2)/16384.0readz=read_data(i2c,0x3B+4)/16384.0returnreadx,ready,readz
Copy this program and paste it in a new empty tab in Thonny's editor. Then save it to your ESP8266's memory into the lib folder. Use the name lucsmpulib.py
If you have any problems with this please refer to the story about the MPU6050 which you can read here: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
The MicroPython program
And here is the program that makes the magic happen.
'''Caravan and Mobile Home leveling aidhttp://lucstechblog.blogspot.com/Version with http serverThe x and y values are roundedESP is configured as Access Point'''frommachineimportPin,I2Cimportutimeimportmathfromlucsmpulibimportinit_mpu,get_dataimportsocketimportnetworkssid='Caravan-Leveler'password='123456789'ap=network.WLAN(network.AP_IF)ap.active(True)ap.config(essid=ssid,password=password)whileap.active()==False:passprint('Connection successful')print(ap.ifconfig())i2c=I2C(scl=Pin(5),sda=Pin(4),freq=400000)# esp8266init_mpu(i2c)s=socket.socket(socket.AF_INET,socket.SOCK_STREAM)s.bind(('',80))s.listen(5)defwebpage():readx,ready,readz=get_data(i2c)x=math.atan2(ready,math.sqrt(readx*readx+readz*readz))*180/math.piy=math.atan2(-readx,math.sqrt(ready*ready+readz*readz))*180/math.piz=math.atan2(readz,math.sqrt(readx*readx+ready*ready))*180/math.piprint("=======================================================")print(1,x)# Tilt angles X-axisprint(2,y)# Tilt angles Y-axisif(x<=0):x=math.floor(x)else:x=math.ceil(x)if(y<=0):y=math.floor(y)else:y=math.ceil(y)html=""html=html+'<!DOCTYPE html>'html=html+'<html>'html=html+'Hi, this is the Pico'html=html+'<br>'html=html+'===================='html=html+'<br>'html=html+'X = '+str(x)html=html+'<br>'html=html+'Y = '+str(y)html=html+'<br>'html=html+'</html>'return(html)whileTrue:conn,addr=s.accept()print('Got a connection from %s'%str(addr))request=conn.recv(1024)print('Content = %s'%str(request))conn.send('HTTP/1.1 200 OK\n')conn.send('Access-Control-Allow-Origin: *\n')conn.send('Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS\n')conn.send('Access-Control-Allow-Headers: Content-Type\n')conn.send('Content-Type: text/html\n')conn.send('\n')response=webpage()conn.send(response)conn.close()
These lines import the necessary libraries. Quite a lot. All the libraries (except lucsmpulib) are included in the standard installation of MicroPython. The only extra library is lucsmpulib which you can install as discussed above.
This is where the access point is created. The name of the access point (which you can find in the wifi section in your phone) is Caravan-Leveler and it's password is 123456789. You can change the name and password to your own liking but make sure to use something that is easy to remember.
A function is created that builds the webpage that is going to be send to your phone or tablet. The function starts with getting the raw x,y and z data from the MPU6050 and then uses some complicated math to recalculate this into human readable x,y and z degrees. We are not going to use the z value though.
For our convenience and only for testing purposes the calculated values are printed in Thonny's shell. Please be aware that this only works when the ESP is connected to your computer through USB. In the real world you will have the ESP powered by the batteries and then there is no connection to your computer.
SAFETY WARNING: Do not connect the ESP8266 to your computer with an USB cable while the batteries are placed. This might damage the ESP8266 or even damage your computer beyond repair. Use the batteries or the USB connection. I accept no responsibility for any damage done by not following these rules.
html=""html=html+'<!DOCTYPE html>'html=html+'<html>'html=html+'Hi, this is the Pico'html=html+'<br>'html=html+'===================='html=html+'<br>'html=html+'X = '+str(x)html=html+'<br>'html=html+'Y = '+str(y)html=html+'<br>'html=html+'</html>'return(html)
These are the lines that build the actual webpage. Do not alter anything of these lines or the program on your phone (which is to follow) might not work.
whileTrue:conn,addr=s.accept()print('Got a connection from %s'%str(addr))
The endless loop constan looks if some device is asking for a connection. If that is so a message is printed in Thonny's shell. Again: this is only for debugging purposes and not functioning in a real world environment.
This is very important. These lines are a safety measure from webservices. These lines assure that an external device (your phone/tablet) can get access to the data on this ESP. If these lines are omitted your phone's connection to the ESP will be rejected. This was covered on a previous story here on this weblog which you can find here: http://lucstechblog.blogspot.com/2024/03/solving-cors-error-in-micropython.html
response=webpage()conn.send(response)conn.close()
The last step is to send the webpage and close the connection.
That's the complete software for the ESP8266 caravan/mobilehome leveling tool.
First test.
Let's see if this functions like we intended.
First step is to open your wifi settings on your phone.
In the Wifi settings there might be a listing of several access points in the environment. At your actual campsite I doubt there are so many as seen here. Look for the access point with the name Caravan-Leveler. Click on that to activate the connection.
The phone might ask for a password when you make the connection for the first time and then fill in 123456789. If you have changed the name of the Access point and Password in the above program look for the right name and fill in your chosen password.
Then open a web-browser on your phone. In the web-browser fill (in the search bar) in the IP address of the Access-Point. ESP8266's always have 192.168.4.1
And here is the web-page that your browser will show. The X and Y values will be different of course and depending on the angle your caravan-leveler is at. As you can see in my test the X value was 32 so the leveler was tilted.
Try and play with this a bit.
Please try and play with this setup a bit. Use a set triangle (geo-driehoek in Dutch) to put your Caravan-Leveler at a certain angle and look what values the webpage shows.
Please note that every time you want a new reading you will have to refresh the webpage.
Next step.
This is fun but not very practical. Next step is a nice looking webpage with a red dot that moves over the screen showing at what angle the caravan-leveler is. I actually made two versions of the software. One version in Javascript which you can convert into an APP for Android or use in your browser. And the other version is an APP made in APP-Inventor. But that is for next episode.
I made a project that helps with leveling your caravan or motorhome !!
The story.
Last summer we went on a holiday. And we always go camping. We camp with a tent. But on most camping sites nowadays lots of people have caravans or motorhomes. The first thing you need to do with a caravan or motor-home is to set it level. If it is not things will roll from your table. Water will not go down the drain or you will tumble out of your bed. OK I know that last one is extreme.
I saw a lot of people that were struggling with getting their caravan/motorhome horizontal. They put a leveler in the doorway. Went to the blocks and adjusted them, then went back to the leveler to see if it was horizontal. Then they went back to the block, adjusted again and went back to look at the leveler etc.
Hey in a motorhome you can put the leveler on your dashboard and then just ride up the blocks till your horizontal?? No does not work that way because most dashboards are tilted. Ok then put the leveler on a table. Well that does not work either as the table is behind the driver so he can't see if it's horizontal.
So then I got an idea. Why not build an electronic device that you can put on your motorhome/caravan's table. And then that device sends it data to an app on your phone. Then you can go outside and look at your phone's screen while leveling your caravan/motorhome !!
The above picture shows a screendump of two versions of my caravan and motorhome leveling aid. The picture on the left shows a screendump from a JavaScript program which run's in your phone's browser. The picture on the right side shows the output from a dedicated app for your phone.
I made several versions of the software before I was satisfied and decided these were the final versions. Both will be published in the next story on this weblog so keep following. In this story I'll show you how to build the electronics.
And of course you can use this for many other things like DIY home improvement projects as this is not just a caravan leveler but a general remote leveling aid.
Here is a video that demonstrates how it functions. As you can see the device works on batteries and is wireless connected to a phone. There is a delay build in the app. Shortening the delay time will make the ball move smoother. That is expalined in the story about building the app.
What you'll need
To build this project you will need: - A battery holder for 3 AA or 3 AAA batteries - A small on-of switch - A led (I used a clear red one) - A 220 Ohm delimiting resistor - Female headers for the MPU6050 and ESP8266 - A Wemos D1 Mini (ESP8266) - An MPU6050 - An enclosure (I printed mine)
I used a clear red led as that gives the best visibility in broad daylight. The led and the switch were added because in de test phase I often forgot to switch set set off so the batteries got drained. The led reminds you that the power is still on.
Please be aware that you do need a microcontroller with Wifi. The controller will send it's data over Wifi to the mobile phone.
If you are very confident about soldering you can leave the female headers out, but I do not recommend that.
The program for the microcontroller is written in MicroPython. This makes it easy to replace the Wemos D1 Mini by an ESP32 Dev board or a Raspberry Pi Pico W. You will just have to adjust the pin numbers in the program. And of course the enclosure I build will not fit as these controllers are larger.
The hardware setup
The first setup was made without the batteries. I tested everything while the Wemos was attached to my computer and powered over the USB connection.
This was the initial setup. This is the setup as described in the previous story. This was ok for testing while it was connected to my computer.
And this is the schematics for the setup with the battery. For your convenience I give the connections verbally.
- The GND of a 3 pack AAA or AA batteries is connected to the GND of the ESP8266 and the GND of the MPU6050. Next to that it is connected to a 220 Ohm delimiting resistor that is connected to a led.
- The VCC (+) of the battery pack is connected to the common connection (middle) of an on-off switch.
- The ON pin of the on-of switch is connected to the led and to the 5V pin of the ESP8266
- The MPU6050 needs 3V3 and is powered from the 3V3 pin of the ESP8266
- The SCL pin of the MPU6050 is connected to D1 (pin 5) of the ESP8266
- The SDA pin of the MPU6050 is connected to D2 (pin 4) of the ESP8266
Be Carefull: NEVER CONNECT THIS PROJECT TO YOUR COMPUTER WITH AN USB CONNECTION WHILE THERE ARE BATTERIES IN THE BATTERY HOLDER. YOU MIGHT DAMAGE YOUR WEMOS OR EVEN YOUR COMPUTER THAT WAY.
So for testing leave the batteries out and connect to the computer with USB. For real time use disconnect the computer and use the batteries.
And here is the stripboard setup. Cut the stripboard so it is as large as actually needed otherwise it will not fit in the below presented enclosure. Even better (maybe): 3D print the enclosure and then make the stripboard fit before soldering the electronics to it. Or cut the stripboard to fit into your own enclosure.
Make sure the stripboard lines beneath the Wemos D1 Mini are cut as otherwise the upper and lower pins are connected and that is something you definitely don't want.
The enclosure
Like stated before I designed an enclosure for this project and 3D printed it.
This is how the complete setup looks. The left lid on the box is white and that is the battery compartment. The right side's lid is purple and that is where the electronics reside. Please note that this enclosure is not water tight so keep it away from rain and moisture. When everything is build and tested you can glue the right-side lid on the enclosure. The left side needs to stay open, of course, to change the batteries.
This is a closeup on how I fitted the stripboard into the enclosure.
And this is how the complete setup looks. I used hot glue to secure the switch and the led to the enclosures wall. And I used screw connectors for the connections of the switch and the led. That is not necessary but makes assembling and disassembling easier.
At the left side of the casing is a gap that makes the USB connector accessible.
Some notes:
- Make sure the headers for the MPU6050 are soldered completely vertical (90 degrees) to the stripboard. If they have an inclination that will influence your readings. - I made some small strips of a few mm height and put these at the sides of the casing. The stripboard rests on these so the stripboard does not rest on the soldered spots which might incline the print and influence the readings. - You could power the setup with a powerbank or from a computer with the usb connection on the Wemos. But an USB cable might put some tension on the Wemos and might give the stripboard an inclination and that influences the readings of the MCU6050.
Generally said: make sure that the stripboard is completely horizontal in the casing. And never power through the USB and with batteries at the same time.
The STL files.
There are 3 STL files. One for the box and 2 for the lids. Please be aware that the lid for the battery compartment is different from the lid for the electronics compartment. And yes, I forgot to make a hole for the led so I just drilled one.
Here is a link to the STL files so you can print your own casing. You can however use any casing you like as long as the bottom is perfectly flat.
