Direction finding belt
Electronics for a belt that indicates magnetic north.
Schematic. This runs off a single Li-Po cell and drives up to 16 pager motors.
R3/R2 is used to monitor voltage of battery (against the VREF internal to the mega8)
L1 is to filter some of the noise coming off the motors.
The IRF7104's are used to drive a 4x4 matrix of up to 16 pager motors.
Partial parts list from digikey: Qantities are way over in some cases. Will stock the spare parts box..
Note that the HMC6352 is not on this list. It's $US35 each!
| Index | Quantity | Part Number | Description | Customer Reference | Backorder Quantity | Unit Price USD |
Extended Price USD |
|---|---|---|---|---|---|---|---|
1 |
20 |
Y4104CT-ND |
RES ARRAY 100K OHM 5% 4 RES SMD |
|
0 |
0.08000 |
$1.60 |
2 |
10 |
IRF7104-ND |
MOSFET 2P-CH 20V 2.3A 8-SOIC |
|
0 |
1.96900 |
$19.69 |
3 |
20 |
160-1414-1-ND |
LED GREEN CLEAR 0805 SMD |
|
0 |
0.08700 |
$1.74 |
4 |
5 |
ATMEGA8-16AU-ND |
IC AVR MCU 8K 16MHZ 5V 32TQFP |
|
0 |
3.55000 |
$17.75 |
5 |
20 |
PCC1906CT-ND |
CAP .12UF 10V CERAMIC X5R 0603 |
|
0 |
0.17600 |
$3.52 |
6 |
50 |
P100KGCT-ND |
RES 100K OHM 1/10W 5% 0603 SMD |
|
0 |
0.03820 |
$1.91 |
7 |
50 |
P1.0KGCT-ND |
RES 1.0K OHM 1/10W 5% 0603 SMD |
|
0 |
0.03820 |
$1.91 |
8 |
10 |
495-2654-1-ND |
INDUCTOR 680UH 61MA 1210 10% |
|
0 |
0.50200 |
$5.02 |
9 |
10 |
IRF7103Q-ND |
MOSFET N-CH 50V 3A 8-SOIC |
|
0 |
0.82500 |
$8.25 |
| Subtotal | $61.39 | ||||||
The board itself comes out to about 22x37mm. A fair bit of that is wasted space due to the 0.1" pitch headers for the JTAG programming interface. Switching to 1mm pitch headers would help, but I don't think it's worth it on this rev.
