Components and supplies
Capacitor 100 nF
Capacitor 100 µF
Jumper wires (generic)
Toggle Switch, Toggle
Relay (generic)
External handset/mic plug for your amateur radio
Arduino UNO
LED (generic)
Tools and machines
Solder Wire, Lead Free
Amateur Radio
Soldering iron (generic)
Project description
Code
Fox Hunting Radio Keyer
arduino
The Arduino that keys up the radio to transmit and sends the Morse code to identify itself.
Fox Hunting Radio Keyer
arduino
The Arduino that keys up the radio to transmit and sends the Morse code to identify itself.
Downloadable files
Schematic for the fox hunt radio's keyer
Schematic for the fox hunt radio's keyer
Comments
Only logged in users can leave comments
Anonymous user
2 years ago
Nanos must be quite robust. Programmed the Nano, hooked up a 5v relay and a small speaker. Powered it all up via USB and let it run for 3 days. Ran perfectly. Then I saw comments about the diode for the relay. Ooops, didn't have one of those in - but it's working. So, hooked up a radio and it all went wonky. Just did order up the caps to put in to prevent that known issue. Got 100 1N4007 diodes of the Zone of Ama for about $5.00 on the way. Sure won't hurt to toss one in there, JIC. Building up 8 of these for the local ham club - look to have some fun!
Anonymous user
2 years ago
Newbie... Please describe where I type my text to be sent.
nfarrier
2 years ago
It's in line 78 of the code.
Anonymous user
2 years ago
Could you please put a date on that schematic, so that people can see that you have addressed the latest comments? I saw a comment elsewhere that the diode is still back to front. VK3BT
nfarrier
2 years ago
I've updated the schematic. Sorry it's taken so long.
glennedi
2 years ago
Hi nfarrier You need a diode across the relay coil not a capacitor. When you power off the relay coil the magnetic field collapses and induces a voltage into the wire, it is this spike which is probably causing your Arduino to reset. Reference: https://electronics.stackexchange.com/questions/100134/why-is-there-a-diode-connected-in-parallel-to-a-relay-coil
nfarrier
2 years ago
Thank you. I made the change. The link was helpful. I also found a great demonstration of why they're important here: https://www.youtube.com/watch?v=5kjtiY9gxGM
Anonymous user
2 years ago
Love the project. The anti-spike diode on the relay should be reversed. They go in reversed biased, not forward biased. Forward biased = short to ground.
Anonymous user
2 years ago
What kind of Relay (generic) do you use? it's a 5 volt Relay?
Anonymous user
2 years ago
I would suggest you the following: a) Put an 1N4007 diode in parallel with the relay coil to cancel the high voltage spikes when the relay coil is released. b) Probably the relay coil can demand more current than the micro controller leg can sink, this can lead in a premature degrading or destruction of the uC. c) As a way to improve the circuit, most radios can be keyed using a simple transistor, avoiding this way the relay use, potentially extending the gadget battery life. 73's de YV1HX
nfarrier
2 years ago
Thank you. I made the change. In the comment above I put a link to the best demonstration of your point B. I though about your third point, but I wanted to make sure I completely isolated my circuit from the radio keying.
Anonymous user
2 years ago
Hi, I love this project so I built one but I can't figure out what I did wrong. It turns the radio on through the relay and I can hear it transmitting just fine except the morse code ID doesn't start until after the radio shuts off. I can see the arduino (uno R3) sending my call sign (by the led) but only after the relay shuts off the radio. Any help will be appreciated. Thanks
nfarrier
2 years ago
I realize this was a long time ago, unfortunately I didn't see a notification that you'd posted a problem. Are you still in need of help, or did you get it to work?
Anonymous user
3 years ago
Could you please put a date on that schematic, so that people can see that you have addressed the latest comments? I saw a comment elsewhere that the diode is still back to front. VK3BT
nfarrier
2 years ago
I've updated the schematic. Sorry it's taken so long.
Anonymous user
4 years ago
Nanos must be quite robust. Programmed the Nano, hooked up a 5v relay and a small speaker. Powered it all up via USB and let it run for 3 days. Ran perfectly. Then I saw comments about the diode for the relay. Ooops, didn't have one of those in - but it's working. So, hooked up a radio and it all went wonky. Just did order up the caps to put in to prevent that known issue. Got 100 1N4007 diodes of the Zone of Ama for about $5.00 on the way. Sure won't hurt to toss one in there, JIC. Building up 8 of these for the local ham club - look to have some fun!
Anonymous user
5 years ago
What kind of Relay (generic) do you use? it's a 5 volt Relay?
huntercf
5 years ago
Hi, I love this project so I built one but I can't figure out what I did wrong. It turns the radio on through the relay and I can hear it transmitting just fine except the morse code ID doesn't start until after the radio shuts off. I can see the arduino (uno R3) sending my call sign (by the led) but only after the relay shuts off the radio. Any help will be appreciated. Thanks
nfarrier
2 years ago
I realize this was a long time ago, unfortunately I didn't see a notification that you'd posted a problem. Are you still in need of help, or did you get it to work?
kmikemoo
5 years ago
Love the project. The anti-spike diode on the relay should be reversed. They go in reversed biased, not forward biased. Forward biased = short to ground.
Anonymous user
5 years ago
Newbie... Please describe where I type my text to be sent.
Anonymous user
5 years ago
I would suggest you the following: a) Put an 1N4007 diode in parallel with the relay coil to cancel the high voltage spikes when the relay coil is released. b) Probably the relay coil can demand more current than the micro controller leg can sink, this can lead in a premature degrading or destruction of the uC. c) As a way to improve the circuit, most radios can be keyed using a simple transistor, avoiding this way the relay use, potentially extending the gadget battery life. 73's de YV1HX
nfarrier
2 years ago
Thank you. I made the change. In the comment above I put a link to the best demonstration of your point B. I though about your third point, but I wanted to make sure I completely isolated my circuit from the radio keying.
glennedi
5 years ago
Hi nfarrier You need a diode across the relay coil not a capacitor. When you power off the relay coil the magnetic field collapses and induces a voltage into the wire, it is this spike which is probably causing your Arduino to reset. Reference: https://electronics.stackexchange.com/questions/100134/why-is-there-a-diode-connected-in-parallel-to-a-relay-coil
nfarrier
2 years ago
Thank you. I made the change. The link was helpful. I also found a great demonstration of why they're important here: https://www.youtube.com/watch?v=5kjtiY9gxGM
dephillipsmi
7 months ago
For this to properly compile with the latest version of the IDE you need to replace all char* reference with char const*