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10-16-2003, 11:21 PM
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#1
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Plankton
Join Date: Jul 2000
Location: Los Angeles
Posts: 13
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Disabling photo transistors?
I want to disable the "drip sensors" on my perisaltic feeder pump. After opening the pump unit, I found two sensors located close to where the drip capsule is at. I'm guessing they are photo transistors(?). The sensors face each other with the drip capsule in the middle. The sesors notify the unit if there are actual liquid passing through. Each sensor has two legs. One longer than the other, I'm assuming its like cathode and anode ends on LEDs. Each leg has a wire connected to it...so there are a total of 4 wires. The four wires then connect to the main electronic circuit board.
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10-17-2003, 12:39 AM
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#2
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ROOTS...ROCKS...REGGAE
Join Date: Feb 2000
Location: south suburbs of Chicago,Il USA
Posts: 1,214
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I dug around and found an old picture of a doser I used to use for kalk. I had the seller disable the same feature before I bought it. You are correct, it is a LED. here's a pic:
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10-17-2003, 06:30 AM
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#3
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Plankton
Join Date: Jul 2000
Location: Los Angeles
Posts: 13
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Sensor.jpg:
Labels "A" and "B" are the locations where the photo diode sensors are at. The curved center is where the drip capsule sits. Two wires connect to each diode (is that what the part is?) via a brown connector.
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10-17-2003, 06:31 AM
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#4
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Plankton
Join Date: Jul 2000
Location: Los Angeles
Posts: 13
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Photodiode.jpg:
One photo diode by itself. Notice the long/ short legs.
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10-17-2003, 06:32 AM
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#5
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Plankton
Join Date: Jul 2000
Location: Los Angeles
Posts: 13
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Front.jpg:
The side of diode that faces the drip capsule.
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10-17-2003, 06:32 AM
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#6
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Plankton
Join Date: Jul 2000
Location: Los Angeles
Posts: 13
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Back.jpg:
Back of the diode.
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10-17-2003, 10:52 AM
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#7
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Reefless Reefer
Join Date: Jun 2002
Location: Durham, NC
Posts: 20,528
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what if you just tape the two sensors together? facing eachother like they are in the clip. you can just let it sit in the case that way, it looks like you have plenty of room. then they would always stay in the one position, correct? if not then put a piece of tape between the sensors.
G~
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10-17-2003, 05:39 PM
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#8
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Plankton
Join Date: Jul 2000
Location: Los Angeles
Posts: 13
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Geoff, I've tried that and it didn't work. They need to sense liquid drips passing by. If I understood it correctly, everytime something passes through, the lighting condition changes. That split second of change is how the photo diodes sense droplets passing through the capsule.
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10-17-2003, 09:43 PM
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#9
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A goof
Join Date: Jan 2000
Location: Plymouth, MN USA
Posts: 2,923
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That sounds like the same problem that I have with my pump. I decided to just fool it with a loop that drips thru it.
What brand do you have?
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10-24-2003, 07:35 AM
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#10
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Plankton
Join Date: Jul 2000
Location: Los Angeles
Posts: 13
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Please click on the following link for pictures and info of my dosing pump.
http://jean.yen.tripod.com/id60.htm
Minnreefer,
Can you give me more detail in how you fool the circuit?
Thanks! |
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10-24-2003, 12:39 PM
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#11
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Reefless Reefer
Join Date: Jun 2002
Location: Durham, NC
Posts: 20,528
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unfortunately i think you are on the right track. i do not think it can be done mechanically. it must be done by programing. whether or not it is just a chip swap or an interface setup i do not know.
sorry, please keep us posted on any updates.
G~
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10-24-2003, 12:51 PM
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#12
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AKA Scooterman
Join Date: Jul 2003
Location: Lafayette, La.
Posts: 352
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I'm taking it you want the pump to always run?
If you remove the two Photo diodes it won't ever run. Each Diode has approximatly .7 voltage drop when conducting. I'll have to look it up but I think in that case you can bypass the sensors by connecting each two legs together or with a low power resistor that would drop .7 volts.
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11-02-2003, 08:14 AM
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#13
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Plankton
Join Date: Jul 2000
Location: Los Angeles
Posts: 13
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BuckWheat,
Do all photo diodes have more or less 0.7 v resistance? Please suggest what spec resistor will I need.... Thanks.
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11-03-2003, 09:59 AM
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#14
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AKA Scooterman
Join Date: Jul 2003
Location: Lafayette, La.
Posts: 352
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I've attached a general purpose diode chart but it will depend Exactly on the Photodiode your equipment is using, there is just too many for me to say without having the Exact part number. I will also link a web page for you to try and find your Exact part number then you can get the specs on what size resistor it will take to replace it, you need to make sure it is the same wattage and resistance, the charts will provide you with that information. Regardless, I highly recommend letting someone with experience to do this for you but if your intent on doing it yourself, you must understand, I'm not right there doing the conversion. It is easily done if you have the right information, Other wise you will burn your UNIT Guaranteed!
The .7 Voltage drop is used for standard silicone diodes, these Photodiodes are specialty diodes and are different for each case, so I must retract that information for your case.
http://www.qphotonics.com/qpdm-1300-1550.htm
http://www.ibsg-st-petersburg.com/pd_gen/pd_gen.htm |
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