5. TeleMini v1.0¶
Fig. 5.1 TeleMini v1.0 Board
TeleMini v1.0 is ½ inches by 1½ inches. It was designed to fit inside an 18mm air-frame tube, but using it in a tube that small in diameter may require some creativity in mounting and wiring to succeed! Since there is no accelerometer, TeleMini can be mounted in any convenient orientation. The default ¼ wave UHF wire antenna attached to the center of one end of the board is about 7 inches long. Two wires for the power switch are connected to holes in the middle of the board. Screw terminals for the e-matches for apogee and main ejection charges depart from the other end of the board, meaning an ideal “simple” avionics bay for TeleMini should have at least 9 inches of interior length.
5.1. TeleMini v1.0 Screw Terminals¶
TeleMini v1.0 has four screw terminals on the end of the board opposite the telemetry antenna. Two are for the apogee and two are for main igniter circuits. There are also wires soldered to the board for the power switch. Using the picture above and starting from the top for the terminals and from the left for the power switch wires, the connections are as follows:
| Terminal # | Terminal Name | Description |
|---|---|---|
| 1 | Apogee - | Apogee pyro channel connection to pyro circuit |
| 2 | Apogee + | Apogee pyro channel common connection to battery |
| 3 | Main - | Main pyro channel connection to pyro circuit |
| 4 | Main + | Main pyro channel common connection to battery |
| Left | Switch Output | Switch connection to flight computer |
| Right | Switch Input | Switch connection to positive battery terminal |
5.2. Using a Separate Pyro Battery with TeleMini v1.0¶
As described in Using a Separate Pyro Battery, using an external pyro battery involves connecting the negative battery terminal to the flight computer ground, connecting the positive battery terminal to one of the igniter leads and connecting the other igniter lead to the per-channel pyro circuit connection. Because there is no solid ground connection to use on TeleMini, this is not recommended.
The only available ground connection on TeleMini v1.0 are the two mounting holes next to the telemetry antenna. Somehow connect a small piece of wire to one of those holes and hook it to the negative pyro battery terminal.
Connecting the positive battery terminal to the pyro charges must be done separate from TeleMini v1.0, by soldering them together or using some other connector.
The other lead from each pyro charge is then inserted into the appropriate per-pyro channel screw terminal (terminal 3 for the Main charge, terminal 1 for the Apogee charge).
5.3. Using an Active Switch with TeleMini v1.0¶
As explained in Using an External Active Switch Circuit, an external active switch requires three connections, one to the positive battery terminal, one to the flight computer positive input and one to ground. Again, because TeleMini doesn’t have any good ground connection, this is not recommended.
The positive battery terminal is available on the Right power switch wire, the positive flight computer input is on the left power switch wire. Hook a lead to either of the mounting holes for a ground connection.
