I need some help with a very basic circuit.
I have a small gumstix computer with a GPIO port that I can vary from 0 power to 3.3 volts / 80milliamps.
This is the computer - **broken link removed**
I need to use this port to trigger the push to talk on a walkie talkie.
I have purchased this board - SparkFun Electronics - Opto-isolator Breakout
I also bought a relay - SparkFun Electronics - Relay SPDT Sealed - Mini
I decided to try and build one step at a time as I do not know what I'm doing!
HEre is the back of the optoisolator board - https://www.sparkfun.com/commerce/images/products/09118-02-L.jpg
My plan was to plug the GPIO port to IN1 and a ground on the gumstix computer to GND on the optoisolator baord. On the other side of the optoisolator I would wire the OUT1 to HVG over the push to talk; thus setting the voltage on the GPIO port to 3.3 would result in transmitting over the radio. This does not work but here is what I did.
To test I replaced the radio with the dc motor from a hand held fan wired to a 9v battery. I replaced the gumstix GPIO port with 3 watch batteries which produce 4 volts / 80 milliamps (close enough![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
I started simple and hooked up the fan to the relay. I then used the 3 small watch batteries to trigger the relay. Success! The fan goes off and on. The relay works and is wired correctly.
I then took my optoisolator and tested it separately. I took the 9 volt battery and plugged into HV and HVG. Using my multimeter I get 9volts and maybe 2 amps across the HV to HVG circuit. Checking the OUT1 to HVG I get nothing.
I plugged in my 4 volt / 80 milliamp watch batteries to IN1 and GND. I still get 9V / 2A from HV to HVG, and now I get 9V / 80milliamps across out1 to HVG.
That sort of makes sense.
Now I am thinking easy enough. 9V / 80milliamps will trigger the relay so lets plug the relay into OUT1 and HVG. To my dismay, plugging the relay in drops the voltage to .5 volts on OUT1. I have no clue why this happens.
Next I thought... lets read the wikipedia article on a transistor and try putting one in front of the relay![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
So I wired the OUT1 to the base, emitter to HVG, collector to relay and relay ground to HVG. No luck.
I think I am close to solving this but just need a little shove in the correct direction.
This will be used for the telemetry system for a high altitude balloon.
**broken link removed**
My wife is thrilled with my project![Roll Eyes :rolleyes: :rolleyes:](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
I have a small gumstix computer with a GPIO port that I can vary from 0 power to 3.3 volts / 80milliamps.
This is the computer - **broken link removed**
I need to use this port to trigger the push to talk on a walkie talkie.
I have purchased this board - SparkFun Electronics - Opto-isolator Breakout
I also bought a relay - SparkFun Electronics - Relay SPDT Sealed - Mini
I decided to try and build one step at a time as I do not know what I'm doing!
HEre is the back of the optoisolator board - https://www.sparkfun.com/commerce/images/products/09118-02-L.jpg
My plan was to plug the GPIO port to IN1 and a ground on the gumstix computer to GND on the optoisolator baord. On the other side of the optoisolator I would wire the OUT1 to HVG over the push to talk; thus setting the voltage on the GPIO port to 3.3 would result in transmitting over the radio. This does not work but here is what I did.
To test I replaced the radio with the dc motor from a hand held fan wired to a 9v battery. I replaced the gumstix GPIO port with 3 watch batteries which produce 4 volts / 80 milliamps (close enough
I started simple and hooked up the fan to the relay. I then used the 3 small watch batteries to trigger the relay. Success! The fan goes off and on. The relay works and is wired correctly.
I then took my optoisolator and tested it separately. I took the 9 volt battery and plugged into HV and HVG. Using my multimeter I get 9volts and maybe 2 amps across the HV to HVG circuit. Checking the OUT1 to HVG I get nothing.
I plugged in my 4 volt / 80 milliamp watch batteries to IN1 and GND. I still get 9V / 2A from HV to HVG, and now I get 9V / 80milliamps across out1 to HVG.
That sort of makes sense.
Now I am thinking easy enough. 9V / 80milliamps will trigger the relay so lets plug the relay into OUT1 and HVG. To my dismay, plugging the relay in drops the voltage to .5 volts on OUT1. I have no clue why this happens.
Next I thought... lets read the wikipedia article on a transistor and try putting one in front of the relay
So I wired the OUT1 to the base, emitter to HVG, collector to relay and relay ground to HVG. No luck.
I think I am close to solving this but just need a little shove in the correct direction.
This will be used for the telemetry system for a high altitude balloon.
**broken link removed**
My wife is thrilled with my project