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modupm [2009/02/25 14:16] seststmodupm [2018/11/03 02:59] (current) – external edit 127.0.0.1
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 ====== Modifying UPM Base unit ====== ====== Modifying UPM Base unit ======
-UPM manufacurs wireless thermometers and weather stations. The temerature sensors communicate via a radio protocol with the base station.+UPM manufactures wireless thermometers and weather stations. The temperature sensors communicate via a radio protocol with the base station.
  
-The protocol sent from the sensors is actually a digital protocol which is AM decoded over 433.92MHz radio signal. The bit rate of the protocol is slow enough to be sampled by the microphone input of a regular PC, so this is the interface we use. All wee need is to find the decoded radio signal, adapt the level and feed it into the microphone input. The NetHome software does the rest.+The protocol sent from the sensors is actually a digital protocol which is AM decoded over 433.92MHz radio signal. The bit rate of the protocol is slow enough to be sampled by the microphone input of a regular PC, so this is the interface we use. All we need is to find the decoded radio signal, adapt the level and feed it into the microphone input. The NetHome software does the rest. 
 + 
 +===== Modifying hardware ===== 
 + 
 +When we open the base unit, we see that UPM has made it easy for us, the radio receiver unit is a separate card (down to the left) where the decoded radio signal is avaliable! There are only three wires connected to the radio board, Power, Ground and signal output. The signal is the decoded digital signal pulses from the transmitters!
  
-When we open the base unit, we see that UPM has made it easy for us, the radio receiver unit is a separate card (down to the left) where the decoded radio signal is avaliable! 
 {{ :open_upm.jpg | Open UPM base unit}} {{ :open_upm.jpg | Open UPM base unit}}
  
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 {{ :upm_scheme.png | Schema of interface}} {{ :upm_scheme.png | Schema of interface}}
  
-The curcuit lowers the level of the signal, the capacitor C1 removes the DC-component of the signal and C2 filters interference. The curcuit is so simple, so we do not need any board to mount it on. We can free mount the components on the 3.5mm jack on the inside. This is not pretty, I am sure you can do it nicer.+The circuit lowers the level of the signal, the capacitor C1 removes the DC-component of the signal and C2 filters interference. The circuit is so simple, so we do not need any board to mount it on. We can free mount the components on the 3.5mm jack on the inside. This is not pretty, I am sure you can do it nicer.
  
 {{ :open_modif1_upm.jpg | Modified UPM base unit}} {{ :open_modif1_upm.jpg | Modified UPM base unit}}
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 Now we have a nice computer interface to the UPM-Unit. Now we have a nice computer interface to the UPM-Unit.
  
-There are some things to note regarding the placement of the base unit. The radio receiver is quite sensitive to disturbance, so you should place it at least two meters away from the computer or other RF emitting equipment (WLAN transmitter an such things). You may also have to put a ferrite bead on the cabel close to the UPM-Unit to block high frequency interfearence from other devices.+===== Connecting ===== 
 + 
 +There are some things to note regarding the placement of the base unit. The radio receiver is quite sensitive to interference, so you should place it at least two meters away from the computer or other RF emitting equipment (WLAN transmitter an such things). You may also have to put a ferrite bead on the cable close to the UPM-Unit to block high frequency interference from other devices
 + 
 +===== Microphone settings ===== 
 + 
 +The microphone input should be set on highest input "volume" but any microphone boost or AGC should be turned off.  
 + 
 +In windows this is done from the control panel under sound settings
  
 +In Linux this is done with the program alsamixer. Start alsamixer from a command prompt (//sudo alsamixer//) and press F5 to see microphone settings. Use Right and left arrow to move to the "Mic Capt"-level and use up arrow to increase gain.
  
modupm.1235567762.txt.gz · Last modified: 2018/11/03 02:57 (external edit)