Simple Wireless Launch Controller

[Mark Weidhaas]

Here is a wireless launch controller I built after tiring of winding up 1000 Ft of wire. Based on readily available non-licensed wireless relay systems and simple plug in ice cube relays this box will hammer any combination of igniters you may have. It has two channels for drag racing and uses a 12 AHr sealed lead acid motorcycle battery. A 12 VDC / 2A charger will charge a day's launches in about an hour. It features both local and remote continuity checks (buttons A & B). Local continuity is confirmed via yellow LEDs in the launch box. The remote checks are reported through a 120 dba alarm siren. I added a disable switch for the siren when used for ground testing. The siren warbles "warnings" (button C) and remains constant when button D (Fire) is depressed. The remote fits easily in your shirt pocket and has an "off" switch per NAR requirements. A digital DC voltmeter is active when the launch box is activated via a keyed switch. Packaged in a cheap Harbor Freight metal toolbox this build can be done for about $250.

 

[shockie]

mor pics please.

 

[teepot]

what's the range?

 

[prfesser]

what's the range?

According to CaryMart.com, the extra-long-range units are good to 5000 m (flat surface). They also have "long range" 3000 m units for somewhat less. A long-range 4-channel receiver unit (no enclosure) and transmitter unit runs around $70.

 

[shockie]

would this be allowed on a NAR launch range? don't shoot me. I'm just asking. I see that the pad unit has a safety key, but would the remote itself also need a key switch? Both the model rocket and HPR safety codes say:

My launch system will have a safety interlock in series with the launch switch, and will use a launch switch that returns to the “off” position when released.

My launch system will have a safety interlock that is in series with the launch switch that is not installed until my rocket is ready for launch, and will use a launch switch that returns to the “off” position when released.

 

[Mark Weidhaas]

My CaryMart remote has an on-off switch. All four buttons on the remote are momentary contacts so they release when not held down. The launch box has a key switch with a removable key. Usable range with the “extra long range” 315 MHz system is at least 1000m even through desert brush. Although my schematic shows a 2019 date the original design was done over 11 years ago. It was based on 27 MHz remote pump/gate wireless relays. It was used at Balls and had the longest range of any remote box at that time, easily 2 miles.