You can use self built sensors from the MySensors project.
Note, at a minimum you will need a gateway (e.g. Arduino) and a radio (e.g. NRF24L01+ (note the "+" at the end)). MySensors will not start without these components!
Install the agocontrol-mysensors package (this guide will assume you know how to access a terminal with permissions to install packages).
apt-get install agocontrol-mysensors
This installation preconfigures the service which should not require any changes. If needed, you can find it here:
You need to create a config mysensors.conf file. The mysensors.conf file tells agoControl the location of your gateway. As such, you need to know yourself. There are many ways to know where your device resides, maybe the easiest is "dmesg" from a terminal. The dmesg output for my Uno, for example, registered as /dev/ttyACM0. Here was the particular line:
cdc_acm 1-1.2:1.0: ttyACM0: USB ACM device
Whatever the location, create the file and insert the required information:
For example, if your gateway location were '/dev/ttyUSB0' insert this:
We must also configure the gateway and repeater-sensor/sensors. In short, download the libraries from the mysensors website  and configure as detailed.
For example, to configure my serial gateway, I downloaded and installed the master library for the Arduino IDE. Upload the correct code to the gateway by selecting "File" -> "Sketchbook" -> "libraries" -> "MySensors" -> "Serial Gateway". Once the code has been uploaded and the radio attached, agoControl should be able to communication with the gateway and any sensors.
systemctl enable agomysensors.service
systemctl start agomysensors.service
systemctl status agomysensors.service
You can run MySensors from the terminal for additional diagnostic information:
For example, I am using an Uno as my gateway and another Uno with a single Dallas temperature sensor. Here was my output:
Waiting for the gateway starts... Done. Requesting gateway version... found v1.4.1 Initializing MySensors controller Register existing devices: - 105/0:temperaturesensor Running MySensors controller...
Mappings can be edited/deleted from the file /etc/opt/agocontrol/maps/mysensors.json .