Project Ginger

Project Status

Flight Tested on F08L01

Problem Statement

We want to send commands to the balloon
We want to recieve data from the balloon
We want to do this in realtime
We want EVERYONE to be able to access this network

Solution Proposal Powerpoint Proposal

Work completed thus far Summer 08 Status Report

  1. Ginger and Ginger Prime V1 PCBs have been designed, ordered, and populated
  2. Ginger and Ginger Prime V1.1 PCBs have been designed (dual band version)
  3. Thermistor onboard has been roughly characterized. Mathcad File
  4. Minimalist (and slowish) Power, and Natural Log approximation functions have been implemented on the MSP430. Mathcad Sheet with C Code
  5. 10 Watt RF amplifier modules assembled and working.
  6. QT based GUI has been written and is functional, if not complete.
  7. Compatible with the TI EZ430-RF2500
  8. See the Allspice Nodes page for more information about the current nodes in operation.

How do I use it?

Please see the How to Use Ginger page

Packet format

Ginger currently supports three packet formats

  1. the "lazy packet" is simply the destination call sign followed by the data. EX "GRX ping"
  2. The "standard packet" shows the packet origin and is useful for history and clarity. EX "GRX:GND rate=384"
  3. The "forwarded packet" is a special packet that is not fully supported yet. This format is used to "bounce" a packet off of a radio like a repeater. EX "ASP:GPS:TMP coords=XXXX" would be re-broadcast by ASP as "TMP:GPS coords=XXXX"

What Ginger Can It Currently Do?

What Ginger Can Currently Do

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*Power Amplifier has been added

  1. Go Into a low power mode when waiting for events (20mA per listening radio)
  2. Listen for Allspice Reports, send an ACK and forward it to the arbiter
  3. The Allspice Controller checks for errors by using a CRC, discarding packets with errors.
  4. The Arbiter listens for Allspice Reports from the Allspice Controller and forwards it on to the TX radio
  5. The Arbiter listens for reports from the ground radio and can forward them onto the Allspice Controller or the Ground Radio
  6. The Arbiter can read and report the main battery voltage of the IC when requested (not the amp battery)
  7. The RX radio can report the received signal strength in dbm of the query packet, and the link quality indicator to the arbiter in the form of a packet addressed to ground
  8. The RX radio can return a "pong" to in the form of a packet addressed to ground passed to the arbiter
  9. The RX radio can alter its channel and data rate
  10. The TX radio can alter its channel and data rate
  11. The TX radio can alter its output power from full (default) down to -36dBm through the UI and report the current level
  12. The TX radio can put the amplifier to sleep and wake it when it needs to transmit
  13. The TX radio can read and report the temperature of the IC when requested

What Ginger Prime Can Currently Do

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*Power Amplifier has been added, USB-> UART chip removes stray interface wires

  1. All controllers except the PC Link go into a low power mode when waiting for events. Not crucial on a USB powered device.
  2. Listen for data on the RX radio, forward it onto the Ginger Prime Arbiter
  3. The RX Radio checks for errors by using a CRC, discarding packets with errors.
  4. The RX radio can alter its channel and data rate
  5. The Arbiter listens for RX reports and forwards them onto the PC Link by default
  6. The Arbiter can send packets from any chip to any other chip onboard by the packet address.
  7. The TX radio can send packets to Ginger
  8. The PC Link sends the report to the PC at 115,200 kbps over a USB virtual com port.
  9. The PC Link recalibrates the 8MHz DCO clock against the 32.768KHz crystal once every 6 seconds, or when told to
  10. The PC Link can recieve up to 64 bytes from the RS232 bus and forward them onto the arbiter
  11. The TX radio can alter its output power from full (default) down to -36dBm through the UI and report the current level
  12. The TX radio can alter its channel and data rate
  13. The TX radio can put the amplifier to sleep and wake it when it needs to transmit
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GUI

  1. Please see the The Spice Rack for more information about the Spice Rack PC-Ginger interface software

Todo list

  1. Build allspice nodes for each team
  2. Allow the GUI to accept/interpret binary data.
  3. Allow allspice network to change channels

Testing

  1. First functional test of an Allspice Node->Ginger->Ginger Prime->RS232 PC! The node was placed into and removed from my freezer. 06-08-2008 Excel File
  2. Functional test of Ginger and the BRB amplifier completed on 08-18-2008. Ginger functional with a bidirectional link of 1 Watt! Range TBD.
  3. Drive-around tests with 6 Watts at 250kbps conducted with Ginger suspended on top of the steam plant in midair on a kite string on 09-04-2008. Link maintained along old Moscow-Pullman highway until the Palouse hills obscured a line of sight link. Success!
  4. Flight Tested on F08L01 SUCCESS! Ginger flown with 6 Watts of downlink power, 12 Watts of uplink power. Contact maintained even on the ground!
  5. Used on Moored launch F08 SUCCESS! Ginger flown with 10 mW of downlink power, 10 mW of uplink power. Node PRS sampled ARIAL's internal pressure at 10hz!

Bugs in REV1 (in order of importance)

  1. Active high sleep on amplifier means that the control circuits will FAIL ON and the amplifier could burn itself out if the battery is ever disconnected or drained. Quick fix is to pull line high with a 10k resistor to minimize battery losses. Replace with P-N pulldown for active low sleep signal in next revision. Op-amp buffering might also be an option.
  2. Pad for the USB->UART chip is the wrong size!!
  3. DVDD is not wired to VDD in ALL CC2500 circuits! (easy greenwire fix)
  4. Frequency drift on PC-Link UART is annoying and requires a daily recalibration of the SMCLK on an O-Scope. A 32.768KHz crystal has been dead-bugged for self-calibration of the DCO clock.
  5. Metal filled holes by PCB antennas are annoying to drill out
  6. 22uF cap on the RF amplifier module will destroy the MOSFET used for power control. Remove component.
  7. Putting the RX Radio JTAG port on the bottom was a stupid idea :)

REV1 Ideas for future revisions

  1. Ginger boards using the new TI msp430F54xx series would mean the entire board could run off of a single chip at significant size savings while operating at full throughput capacity. 16kb of ram would allow for a small store and forward buffer in case of momentary link loss. The new realtime clock module would report data with a more accurate timestamp.
  2. The CC1101 chips can operate at 70cm (430MHz) or 33cm band (915MHz). 33cm band might be more feasible for future cubesat work due to the smaller antennas size. To change between the two bands requires a new matching network which would not be difficult to jumper. New amplifiers would need designed.

Updates in V1.1 (Running list)

  1. New output matching network works for 440MHz and 915MHz
  2. Many many many more ground-tac vias added around rf parts, busy areas.
  3. EMI-hardened Op-amp buffered amplifier voltage added to arbiter ADC
  4. Amplifier enable redesigned using an EMI-hardened op-amp buffer with tunable gain
  5. USB-UART footprint should match
  6. CC2500 DVDD pad fixed

Meeting Notes

PG10/17/07
PG10/24/07
PG11/28/07

Project Contact

Jasper Nance