Radio Control Relay

[rbeckey]

I have had parts and vague plans around for years. I decided to get started with this diagram:

 

[rbeckey]

I have two Seahorse 300 cases, similar to Pelican cases. 10.8x9.9x4.9. One orange and one yellow. I acquired panel plates for them somewhere along the line.

I put in plexiglass floor plate on standoffs. Added a 3S lipo and a remote relay rated at 30 amps.

I added a fuse holder, toggle switch, battery meter, arming light and neutrik connector. I adapted the 3S charging cable to a 4 pole stereo jack and added it to the panel.

 

[rbeckey]

The battery meter monitors temperature with a contact probe which is taped to the battery. It has a power switch of its own. I connected it directly to the battery so I can check the charge without arming the box.

 

[rbeckey]

Wago connectors were used to form positive and negative busses. They are rated at 32 amps. If you've never used them they are very handy. They will connect any wires from 12 to 28 gauge using levers that can be opened and closed repeatedly. Think of a universal wire nut for the 21st century. All exposed metal was covered with heat shrink. Since I only had black wire on hand cheap nail polish was used to color the terminators. The relay was covered by the plastic shell provided.

 

[rbeckey]

They beefed up the circuit for the relay. I think it likely would handle 30 amps but I have fused the system at 20 amps.

 

[rbeckey]

I have to build the ignitor cable and will test with an ignitor tomorrow.

 

[Voyager1]

They beefed up the circuit for the relay. I think it likely would handle 30 amps but I have fused the system at 20 amps.

View attachment 456831

I would use a 10-12A circuit breaker, rather than a 20 A single-use fuse. In any of my single and multichannel launch controllers, I have rarely tripped an ignition circuit breaker in 10 years.

The one in the pic is rated for 15A, but you will only need a 10A one.

 

[OverTheTop]

I agree with Voyager. However if you do use fuses make sure you have about a dozen spares taped in the lid of the launch box.

 

[sghioto]

How are you activating the relay?
Where is that part of the project?
What is that black box shown in post #4, a battery charger?

 

[rbeckey]

The relay is under the black box. I believe he very first image in the second post shows it uncovered beside the battery before the wires went in. I covered it to protect against a short should a wire come loose eventually.

The relay is activated by a small radio controller. Since there are an orange and a yellow box I color coded the buttons as best I could. I am currently figuring out how to switch the remotes. The smaller one has a physical cover that slides over the buttons and prevents them from being pushed. I could probably fit a micro switch or plug of some sort into the larger one.

 

[rbeckey]

The range is shorter than I expected at about 110 feet. After buttoning it up and testing I realized that I did not uncoil the antenna wire on the relay.

Does anyone have experience with these type relays? Will stretching out the antenna wire make a difference?

The good news is that a 10 year old magnalite with a nichrome bridge popped instantly.

 

[OverTheTop]

Does anyone have experience with these type relays? Will stretching out the antenna wire make a difference?

I wouldn't try it on the transmit end, but it may work on the receiver end. It easy to try .

Note that getting it further off the ground will help, probably greatly.

 

[Voyager1]

The range is shorter than I expected at about 110 feet. After buttoning it up and testing I realized that I did not uncoil the antenna wire on the relay.

Does anyone have experience with these type relays? Will stretching out the antenna wire make a difference?

If the relay came with a helically wound antenna then it's probably best to leave it as such. If you stretch it out, it will change the effective impedance of the antenna and potentially reduce the transmitted power. The stretched out length of a helical antenna is not necessarily going to resonate at the transmit frequency. If you do try to stretch it out, then make sure you measure the length, diameter and turn separation of the helix beforehand, so that you can return it to its previous configuration. As OTT suggested, the higher off the ground you can get the Tx and Rx antennas, the better the performance of the system.

 

[rbeckey]

I am hesitant to change it in any way unless it would really extend the range. It came precisely coiled and shaped, not just wound up in a bundle. Thanks for saving me some trouble.

As I only intend to use this for up to G engines, the distance is adequate as is.

 

[OverTheTop]

If it is coiled I would leave it that way. You could just try extending it from the top. Might improve things.

 

[rbeckey]

Both finished and tested. I have a 12 volt lamp I use for testing. I think I'll Velcro it inside one of them for troubleshooting in the field.

I left the fuse holders in for now since I had them on hand. If they prove troublesome I'll switch them for circuit breakers.

 

[teepot]

I would be curios how the remotes work over time. I have had about a dozen of them. Half didn't work out of the box, half would only let a volt or two thru and a couple had no range. One worked for a while then quit. It was supposed to work from 100 yards but only worked from 100 feet. I'm on the verge of getting one from a fireworks/pyrotechnic site.

 

[rbeckey]

About 10-12 years ago I bought the radio relays direct from Carymart. Most of the other parts were sourced locally then. For reasons that are unimportant now I never did more than buy the parts. Recently I was cleaning out my workshop and found the box of miscellaneous parts and the two cases, so I decided to use them. I enjoyed a bit of improvising and assembly. That's more than enough for what I had intended to dispose of or sell at a loss.

Both boxes have set off home made magnalite igniters from more than 100 feet, which is useful for my purpose. No guarantee they'll keep working, but there never is. I'll tackle that problem when it comes up. I saw those pyro controllers. They seem like a turn key solution. Unfortunately they or their parts are probably made in the same place by the same people as the relays.