I have completed the project. A DHT22 sensor, using Thomas Henry's contribution, showing current and historical values on a ST7920 GLCD. Using the latest GLCD driver I was able to add Bar Graphs and Line Graphs of the sensor data. The project has menus implemented via two switches (the Menu button and the Selection button), timing implemented via an external 1 mhz clock signal, the GLCD and the DHT22 sensor.
During normal operation, the Menu button will toggle between the graphs, either Bar or Line Graph, and the menu of options. The Select button will take a new sensor reading in this mode of operation.
To change the graph type or any of the settings, sample sizes, graph type etc use the Menu button and make your selection.
- You can select 100 or 25 samples.
- Samples can be taken over 5s, 15s, 1m, 15m or 60m.
- Samples can be displayed in a Bar Graph or Line Graph.
- For the Bar Graph - you can choice between rH and Temperature. The last 10 samples are displayed.
- For Line Graph - rH and the temp is shown for the number of samples selected. You can also set the upper and lower limit of the Y axis using the menu of choices.
The screen shots below show some of the screens, the video is a more detailed explanation.
Finally, this solution uses a 16f1937. 94% of the available memory. GCB was stable throughout the development cycle with only one minor issue.
I have completed the project. A DHT22 sensor, using Thomas Henry's contribution, showing current and historical values on a ST7920 GLCD. Using the latest GLCD driver I was able to add Bar Graphs and Line Graphs of the sensor data. The project has menus implemented via two switches (the Menu button and the Selection button), timing implemented via an external 1 mhz clock signal, the GLCD and the DHT22 sensor.
During normal operation, the Menu button will toggle between the graphs, either Bar or Line Graph, and the menu of options. The Select button will take a new sensor reading in this mode of operation.
To change the graph type or any of the settings, sample sizes, graph type etc use the Menu button and make your selection.
- You can select 100 or 25 samples.
- Samples can be taken over 5s, 15s, 1m, 15m or 60m.
- Samples can be displayed in a Bar Graph or Line Graph.
- For the Bar Graph - you can choice between rH and Temperature. The last 10 samples are displayed.
- For Line Graph - rH and the temp is shown for the number of samples selected. You can also set the upper and lower limit of the Y axis using the menu of choices.
The screen shots below show some of the screens, the video is a more detailed explanation.
Finally, this solution uses a 16f1937. 94% of the available memory. GCB was stable throughout the development cycle with only one minor issue.
:-)
Last edit: Anobium 2014-06-15
See http://youtu.be/fMq-dtveKu0 for a demonstration video.
A few more photos of the the complete solution.