S3004_1: Schematic of Transmitter with Logic Chip.
PCB Layout: A ZIP archive of the PCB layout files for our A3004 and A3005 combination array prototype circuit board.
Transmitter Top: The Transmitter with Logic Chip (A3004) after its programming extension has been cut off, leaving only the transmitter with its reed relay, battery, logic chip, regulator, VCO, and 32-kHz oscillator. In this view, we see the logic chip side of the boar.
Transmitter Side: In this view, we see the battery mounted over the reed relay side of the board, and the logic chips on the other side. In the versions we shipped to UCL, we mounted the battery over the logic chip on the other side of the board. We subsequently decided, however, that it is better to mount the battery on the same side of the board as the reed relay, because the battery protects the reed relay from impact. The reed relay is fragile, and will break if you drop the transmitter on the floor and the relay happens to take the impact of the fall.
P3004A01.abl: Logic chip program, version 1, which counts transitions of the 32-kHz oscillator, but disables radio transmission. You will find its compiled JEDEC file here. We use this firmware to measure the inactive current consumption of a transmitter. For the three transmitters we tested, this consumption was around 15 μA.
P3004A02.abl: Logic chip program, version 2, which transmits a 30-bit data word ever 2 ms. The data word begins with four 1s, then a single 0, and the twenty bits of a counter that counts 32 kHz transitions. The bottom six bits of this counter are always zero, because it is when they are zero that the transmitter sends out its burst of data. The ring oscillator in this firmware is five gates long, and runs at 50 MHz. The 30 data bits are transmitted at 6 MBits/s, so that the entire 30-bit burst takes 5 μs. You will find its compiled JEDEC file here. We use this firmware to measure the active current consumption of a transmitter. For the three transmitters we tested, this consumption was around 45 μA.
P3004A03.abl: Logic chip program, version 3, which allows you to activate and de-activate the transmitter by closing and opening the reed relay. The 30-bit data transmission still takes place in 4 μs. The ring oscillator is three gates long, and runs at 80 MHz. The first four bits of the transmission are 1s, followed by a singl 0, and then bits 23 down to 6 (T23 down to T6) of a 23-bit counter that counts 32 kHz transitions. After that we have six 0s, and then a singl 1 at the end. You will find its compiled JEDEC file here. We use this version of the firmware to test the performance of the transmitters with range and orientation.
MAX1726EUK18: U1, the 1.8-V regulator, with quiescent current 2 μA.
ispMACH4064Z: U2, the programmable logic chip in a 48-pin thin quad flat pack. The chip's internal logic runs off a 1.8-V supply, and its maximum quiescent current is 10 μA.
MAX2624: U3, the 950-MHz voltage-controlled oscillator, with active current consumption less than 10 mA, and shut-downn current consumption less than 0.1 μA.
OV1564C: U4, the 32-kHz oscillator, with quiescent current 2 μA.